Article

Effects of walking with blood flow restriction on limb venous compliance in elderly subjects

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Venous compliance declines with age and improves with chronic endurance exercise. KAATSU, an exercise combined with blood flow restriction (BFR), is a unique training method for promoting muscle hypertrophy and strength gains by using low-intensity resistance exercises or walking. This method also induces pooling of venous blood in the legs. Therefore, we hypothesized that slow walking with BFR may affect limb venous compliance and examined the influence of 6 weeks of walking with BFR on venous compliance in older women. Sixteen women aged 59-78 years were partially randomized into either a slow walking with BFR group (n = 9, BFR walk group) or a non-exercising control group (n = 7, control group). The BFR walk group performed 20-min treadmill slow walking (67 m min(-1) ), 5 days per week for 6 weeks. Before (pre) and after (post) those 6 weeks, venous properties were assessed using strain gauge venous occlusion plethysmography. After 6 weeks, leg venous compliance increased significantly in the BFR walk group (pre: 0·0518 ± 0·0084, post: 0·0619 ± 0·0150 ml 100 ml(-1)  mmHg(-1) , P<0·05), and maximal venous outflow (MVO) at 80 mmHg also increased significantly after the BFR walk group trained for 6 weeks (pre: 55·3 ± 15·6, post: 67·1 ± 18·9 ml 100 ml(-1)  min(-1) , P<0·01), but no significant differences were observed in venous compliance and MVO in the control group. In addition, there was no significant change in arm compliance in the BFR walk group. In conclusion, this study provides the first evidence that 6 weeks of walking exercise with BFR may improve limb venous compliance in untrained elder female subjects.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... limb venous compliance may also be affected by BFr exercise due to the increased hydrostatic forces in the veins during BFr. compared to non-BFr treadmill walking 4 weeks of BFr treadmill walking increases calf venous compliance (cVc) in older individuals (Iida et al. 2011). currently, it is unclear if a higher volume of low-load resistance training (i.e., performed to fatigue) may elicit similar vascular adaptations as that from low-load BFr resistance training. ...
... Also contrary to our hypothesis, BFr knee extensor resistance training did not increase calf venous compliance. Short-term (6 weeks) BFr treadmill walking increased calf venous compliance in elderly (~67 years) women (Iida et al. 2011). It is possible that the number of training sessions (18 sessions) and/or the duration of blood flow restriction during each training session (~3.5 to ~7.5 min) was insufficient in the present study to induce changes in venous compliance. ...
... It is possible that the number of training sessions (18 sessions) and/or the duration of blood flow restriction during each training session (~3.5 to ~7.5 min) was insufficient in the present study to induce changes in venous compliance. the aforementioned study (Iida et al. 2011) involved 30 training sessions in which participants were under blood flow restriction for 20 min/session. In addition, treadmill walking utilizes the muscles of the lower leg more than knee extensor exercise. ...
Article
To examine the effects of low-load knee extensor training to fatigue with and without blood flow restriction (BFR) on calf vascular conductance, calf venous compliance, and peripheral arterial stiffness in middle-aged individuals. Eleven men (55 ± 8 years) and five post-menopausal women (57 ± 5 years) completed 6 weeks of unilateral knee extensor training with one limb exercising with BFR (BFR limb) and the contralateral limb exercising without BFR (free flow, FF limb). Before and after the training, femoral pulse wave velocity (PWV), calf blood flow (normalized as conductance), and calf venous compliance were measured in each limb. PWV increased following training in both limbs (main effect of time, p = 0.036; BFR limb 8.9 ± 0.8 vs. 9.5 ± 0.9 m/s, FF limb 9.0 ± 1.2 vs. 9.0 ± 1.1; Pre vs. Post). Calf blood flow increased (p = 0.026) in the FF limb (25.0 ± 7.0 vs. 31.8 ± 12.0 flow/mmHg; Pre vs. Post) but did not change (p = 0.831) in the BFR limb (29.1 ± 11.3 vs. 28.7 ± 11.5 flow/mmHg; Pre vs. Post). Calf venous compliance did not change in either limb following training. These results suggest low-load BFR resistance training to fatigue elicits small increases in peripheral arterial stiffness without eliciting concomitant changes in venous compliance. In addition, unlike low-load knee extensor training without BFR, training with BFR did not enhance calf blood flow.
... Endurance exercise is an established intervention for the improvement and maintenance of venous vascular health. For example, it has been reported that venous volume and compliance are increased in the exercising limb (Hernandez & Franke, 2004;Iida et al., 2011;Monahan et al., 2001;Oue et al., 2019) and that venous volume is increased in the non-exercising limb (Miyachi et al., 2001;Oue et al., 2019) after endurance exercise training. In addition, the degree of such venous vascular adaptation with endurance exercise training is greater for interval workloads than for continuous workloads (Oue et al., 2019). ...
... However, some studies have investigated the effects of short-term endurance exercise training on venous vascular properties. In contrast to our findings, those previous studies reported that short-term endurance exercise training for 6-8 weeks caused increases in venous volume and compliance in the exercising limb (Iida et al., 2011; F I G U R E 2 Effect of acute endurance exercise involving interval workload on venous volume (a, c) and venous compliance (b, d) in the calf and forearm. Values are means ± standard deviation. ...
... Many studies have shown that arterial vascular health (e.g., endothelial function and vascular compliance) is improved by both short-term exercise training for 4-8 weeks (Cameron & Dart, 1994;Kakiyama et al., 2005) and acute exercise (Kingwell et al., 1997;Tordi et al., 2010). However, from both previous studies and the present study, venous vascular properties seem to be increased by short-term exercise training for 6-8 weeks (Iida et al., 2011;Miyachi et al., 2001;Oue et al., 2019) but are not likely to be changed by acute exercise (Figures 1-3). These findings suggest that the exercise volume (exercise intensity × duration × frequency) required to improve vascular health following endurance exercise may differ between the arteries and veins. ...
Article
Short-term endurance exercise training for 6-8 weeks leads to increases in venous volume and compliance in the limbs. However, it is not known whether these venous vascular properties are improved by acute endurance exercise. We examined the effects of acute endurance exercise involving continuous or interval workloads on venous volume and compliance in the exercising (calf) and non-exercising (forearm) limbs. Sixteen healthy young volunteers performed cycling exercise involving a continuous workload of 60% heart rate (HR) reserve or an interval workload of 40% HRreserve and 80% HRreserve, alternating every 2 min, for a total of 32 min each. Before and 60 min after acute cycling exercise, venous volume in the calf and forearm was measured by venous occlusion plethysmography during a cuff-deflation protocol with a venous collecting cuff wrapped to the thigh and upper arm and strain gauges attached to the calf and forearm. The cuff pressure was maintained at 60 mmHg for 8 min and was then deflated to 0 mmHg at a rate of 1 mmHg/s. Venous compliance was calculated as the numerical derivative of the cuff pressure-limb venous volume curve. In both the calf and forearm, the cuff pressure-venous volume curve and the cuff pressure-venous compliance relationship did not differ between before and 60 min after exercise involving continuous or interval workloads. These results suggest that acute exercise does not improve venous volume and compliance in both the exercising and non-exercising limbs.
... This study includes 12 RCT studies [6,8,9,[15][16][17][18][19][20][21][22][23], with a total sample size of 378, 169 in the experimental group and 209 in the control group. Table 1 shows the basic information, such as training intervention characteristics, BFR approach and outcome indicators included in the study. ...
... The results indicated that SBP increased in the LL-BFR group, and that this increase was significantly higher than for the control group (WMD = 5.05, 95% CI: [0.63, 9.48], p < 0.05, Figure 4). LL-BFR group, and that this increase was significantly higher than for the control group (WMD = 5.05, 95% CI: [0.63, 9.48], p < 0.05, Figure 4). ...
... The results of the meta-analysis showed that the acute changes in DBP after LL-BFR training were significantly higher than those in the control group (WMD = 4.87, 95% CI: [1.37, 8.37], p < 0.01, Figure 5). LL-BFR group, and that this increase was significantly higher than for the control group (WMD = 5.05, 95% CI: [0.63, 9.48], p < 0.05, Figure 4). ...
Article
Full-text available
Background: The combination of low-load (LL) training with blood flow restriction (BFR) has recently been shown to trigger a series of hemodynamic responses and promote vascular function in various populations. To date, however, evidence is sparse as to how this training regimen influences hemodynamic response and vascular function in older adults. Objective: To systematically evaluate the effects of LL-BFR training on hemodynamic response and vascular function in older adults. Methods: A PRISMA-compliant systematic review and meta-analysis were conducted. The systematic literature research was performed in the following electronic databases from their inception to 30 February 2022: PubMed, Web of Science, Scopus, EBSCO host, the Cochrane Library and CNKI. Subsequently, a meta-analysis with inverse variance weighting was conducted. Results: A total of 1437 articles were screened, and 12 randomized controlled trials with a total 378 subjects were included in the meta-analysis. The meta-analysis results showed that LL-BFR training caused a significant acute increase in heart rate (WMD: 4.02, 95% CI: 0.93, 7.10, p < 0.05), systolic blood pressure (WMD: 5.05, 95% CI: 0.63, 9.48, p < 0.05) and diastolic blood pressure (WMD: 4.87, 95% CI: 1.37, 8.37, p < 0.01). The acute hemodynamic response induced by LL-BFR training is similar to that elicited by high-load (HL) training. Training volume, cuff pressure and width were identified as significant moderators in our subgroup and meta-regression analyses. After 30 min of training, resting systolic blood pressure significantly decreased (WMD: -6.595, 95% CI: -8.88, -3.31, p < 0.01) in the LL-BFR training group, but resting hemodynamic indexes exhibited no significant differences compared with common LL and HL training; long-term LL-BFR training resulted in significant improvements in flow-mediated vasodilation (FMD) (WMD: 1.30, 95% CI: 0.50, 2.10, p < 0.01), cardio ankle vascular index (CAVI) (WMD: 0.55, 95% CI: 0.11, 0.99, p < 0.05) and ankle brachial index (ABI) (WMD: 0.03, 95% CI: 0.00, 0.06, p < 0.05) in older adults. Conclusion: This systematic review and meta-analysis reveals that LL-BFR training will cause an acute hemodynamic response in older adults, which can return to normal levels 30 min after training, and systolic blood pressure significantly decreased. Furthermore, the beneficial effect of LL-BFR training on vascular function is to improve FMD, CAVI and ABI of older adults. However, due to the influence of the quality of the included studies and the sample size, more high-quality studies are needed to confirm such issues as BFR pressure and training risk.
... Six weeks of cycling with one leg under blood flow restriction and the opposing leg unrestricted, resting femoral diameter [60] and femoral blood flow during exercise [61] only increased in the blood flow restricted leg when compared to pre-training. Additionally, when compared to a non-exercise control group, elderly women saw improvements in venous compliance of the legs, but not in the arms, after 6 weeks of blood flow restriction walking, suggesting a localized positive effect of this modality [62]. It should be noted, this adaptation was not compared to walking alone, so it remains unknown whether the adaptation was attenuated, augmented, or unaffected by the addition of blood flow restriction. ...
... First, acute changes in vascular function may not be reflective of chronic changes. Second, the exercise protocol used by Renzi et al. [58] comprised 5 sets of walking for 2 min, separated by 1 min of rest, which is half of the overall duration per session of the chronic studies which employed 20 min of continuous walking with no rest [59,62]. Third, although the background activity level of participants was not thoroughly described, a 2 mph walking speed for a younger active population [58] may not be an adequate stimulus, with or without blood flow restriction, when compared to ∼2.5 mph for sedentary elderly males [59] and females [62]. ...
... Second, the exercise protocol used by Renzi et al. [58] comprised 5 sets of walking for 2 min, separated by 1 min of rest, which is half of the overall duration per session of the chronic studies which employed 20 min of continuous walking with no rest [59,62]. Third, although the background activity level of participants was not thoroughly described, a 2 mph walking speed for a younger active population [58] may not be an adequate stimulus, with or without blood flow restriction, when compared to ∼2.5 mph for sedentary elderly males [59] and females [62]. ...
Article
Blood flow restriction is growing in popularity as a tool for increasing muscular size and strength. Currently, guidelines exist for using blood flow restriction alone and in combination with endurance and resistance exercise. However, only about 1.3% of practitioners familiar with blood flow restriction applications have utilized it for vascular changes, suggesting many of the guidelines are based on skeletal muscle outcomes. Thus, this narrative review is intended to explore the literature available in which blood flow restriction, or a similar application, assess the changes in vascular structure or function. Based on the literature, there is a knowledge gap in how applying blood flow restriction with relative pressures may alter the vasculature when applied alone, with endurance exercise, and with resistance exercise. In many instances, the application of blood flow restriction was not in accordance with the current guidelines, making it difficult to draw definitive conclusions as to how the vascular system would be affected. Additionally, several studies report no change in vascular structure or function, but few studies look at variables for both outcomes. By examining outcomes for both structure and function, investigators would be able to generate recommendations for the use of blood flow restriction to improve vascular structure and/or function in the future.
... BFR training has been studied in the preclinical setting through animal testing, primarily in an equine model. 1 Preliminary clinical testing includes lowintensity walk training in the elderly and more targeted studies looking at the muscle of younger, healthy subjects; the combi nation of these studies show BFR training being linked to changes in hormones, myogenic stem cell prolifera tion, and protein synthesis. [1][2][3][4][5][6][7] It has also been proved to be safe and effective in achieving muscular strength and hypertrophy in healthy adults or in elderly patients with sarcopenia. 3,8,9 BFR training is not widely used in rehabilitation for chronic muscle weakness secondary to trauma. ...
... [1][2][3][4][5][6][7] It has also been proved to be safe and effective in achieving muscular strength and hypertrophy in healthy adults or in elderly patients with sarcopenia. 3,8,9 BFR training is not widely used in rehabilitation for chronic muscle weakness secondary to trauma. Based on a search of the literature through online databases (using "occlusion training" or "blood flow restriction" and "rehabilitation" or "physical ther apy"), this case series is the first to incorporate BFR use as part of a physical therapy rehabilitation protocol in a patient population who has difficulty performing high resistance exercises due to their injuries. ...
... 18,20 Early human studies indicate muscle hypertrophy and strength gains in healthy adults and eldery patients with sarcopenia. 2,3,8,19 Some studies have also indicated that BFR maintains these gains for a longer duration after training compared with standard practices. 6 A persistent problem in chronic injuries, especially in the extremities, is regaining the required strength and endur ance of atrophied or traumatized musculature. ...
Article
Full-text available
Background: Blood flow restricted (BFR) training, the brief and partial restriction of venous outflow of an extremity during low load resistance exercises, is a safe and effective method of improving strength in healthy, active individuals. A relatively unexplored potential of this adjunctive modality lies in treating patients with severe musculoskeletal trauma, persistent chronic quadriceps and hamstring weakness despite traditional therapy, and low improvement during early postoperative strengthening. Methods: This case series describes patients with chronic quadriceps and hamstring weakness who received an intervention of BFR at low loads, 20% of 1 repetition max (1RM), to restore strength. A case series was conducted of seven patients, all located at one hospital and all with traumatic lower extremity injuries. The seven patients were treated at the same medical center and with the same BFR protocol. All seven patients had isokinetic dynamometer testing that showed persistent thigh muscle weakness despite previous rehabilitation with traditional therapy and 35% to 75% peak torque deficit in either knee extension or flexion compared with the contralateral lower extremity. Patients underwent 2 weeks of BFR training therapy using a pneumatic tourniquet set at 110mmHg while performing leg extensions, leg presses, and reverse leg presses. All affected extremities were retested after 2 weeks (six treatment sessions). Dynamometer measurements were done with flexion and extension at two speeds: 90° and 300°/sec. The data recorded included peak torque normalized for body weight, average power, and total work. Results: All seven patients demonstrated improvements in peak torque, average power, and total work for both knee flexion and extension, with power being the most improved overall. Peak torque improved an average of 13% to 37%, depending on contraction direction and speed. Average power improved an average of 42% to 81%, and total work improved an average of 35% to 55%. Conclusion: BFR therapy at low loads can affect improvement in muscle strength in patients who are unable to perform high-resistance exercise or patients who have persistent extremity weakness despite traditional therapy.
... Of the 22 studies qualified for critical reading of abstracts, ten were excluded because subjects were not older adults or because they assessed the acute effect of training with BFR on some outcome. Thus, a total of 12 studies were included in the review [6][7][8][9][10]12,13,[16][17][18][19][20] . ...
... Iida et al. 18 There were no significant differences between groups in the resting levels of CK, IL-6, IGF-I, IGFBP-3 and Testosterone. In addition, there were no significant changes in the crosssectional area of the muscle, but a trend towards a significant decrease in percentage changes in subcutaneous thigh flexion. ...
... Continue… bone health 16 , increased venous compliance 18 , improved peak oxygen uptake (VO 2 ), increased blood flow 17,18 and improved balance, overall performance, and increased growth hormone concentration 8 . According to criterion proposed by Downs and Black 15 , the average methodological quality score assigned to the articles selected was 16. ...
Article
Full-text available
Low-intensity training with blood flow restriction (BFR) has been suggested as an alternative to physical training for older adults. The present study aimed to review the literature regarding the effect of training with BFR for older adults. The search strategy consisted of experimental studies aimed at verifying the effects of training with BFR on any outcome in older adults. An electronic search in PubMed / Medline, Bireme Scielo, Lilacs and Cochrane Library databases, published until December 2015 was conducted. Experimental studies that considered individuals aged 50 years and over published in English or Portuguese, were included. The Downs & Black scale was used to assess the methodological quality of articles. Of the 60 studies, 12 were included in the review. Training with BFR improved body mass, torque and muscle power; functional capacity; bone health; venous compliance; peak oxygen uptake; and blood flow; balance and overall performance. The methodological quality of studies had mean score of 16.2 points (SD = 1.6). The prescription of low-intensity exercises with BFR may be an alternative of training for older adults. However, future studies should address the methodological quality, especially external validity and power, the main gaps in articles reviewed in this study. © 2018, Universidade Federal de Santa Catarina. All rights reserved.
... In addition to the adaptation of arterial vessels due to regular exercise, some cross-sectional studies have reported that calf venous compliance was greater in trained subjects who engaged in habitual endurance exercise for at least 2 years compared with sedentary subjects (Monahan, Dinenno, Seals, and Halliwill, 2001;Hernandez and Franke, 2004), indicating that chronic endurance exercise could also enhance venous compliance. In addition, some longitudinal studies have shown that increased calf venous compliance in the exercising limb was also observed after continuous exercise training (C-TRA) for 6-8 weeks (Iida et al., 2011;Scholten, Hopman, Lotgering, and Spaanderman, 2015), although forearm venous compliance in the non-exercising limb was unchanged after C-TRA for 6 weeks (Iida et al., 2011). These previous studies suggest that the adaptation of venous compliance in response to C-TRA may occur specifically in the exercising limb; however, the effect of interval exercise training on venous compliance in exercising and non-exercising limbs is not well understood. ...
... In addition to the adaptation of arterial vessels due to regular exercise, some cross-sectional studies have reported that calf venous compliance was greater in trained subjects who engaged in habitual endurance exercise for at least 2 years compared with sedentary subjects (Monahan, Dinenno, Seals, and Halliwill, 2001;Hernandez and Franke, 2004), indicating that chronic endurance exercise could also enhance venous compliance. In addition, some longitudinal studies have shown that increased calf venous compliance in the exercising limb was also observed after continuous exercise training (C-TRA) for 6-8 weeks (Iida et al., 2011;Scholten, Hopman, Lotgering, and Spaanderman, 2015), although forearm venous compliance in the non-exercising limb was unchanged after C-TRA for 6 weeks (Iida et al., 2011). These previous studies suggest that the adaptation of venous compliance in response to C-TRA may occur specifically in the exercising limb; however, the effect of interval exercise training on venous compliance in exercising and non-exercising limbs is not well understood. ...
... Cross-sectional studies have shown that habitual endurance exercise training can lead to increased calf venous compliance (Monahan, Dinenno, Seals, and Halliwill, 2001;Hernandez and Franke, 2004), although the time frame for such adaptation is not well understood. Some studies have reported that endurance training for 6-8 weeks increased calf venous compliance in older subjects (Iida et al., 2011) and formerly preeclamptic women (Scholten, Hopman, Lotgering, and Spaanderman, 2015), who already had lower venous compliance before exercise training. To our knowledge, this present study is the first to demonstrate that interval endurance exercise training for 8 weeks can enhance calf venous compliance in healthy young subjects, who would likely have relatively higher calf venous compliance before training. ...
Article
Full-text available
We examined whether the effect of short‐term endurance exercise training on venous compliance in the calf and forearm differed between continuous and interval workloads. Young healthy volunteers (10 women and 16 men) were randomly assigned to continuous (C‐TRA; n = 8) and interval (I‐TRA; n = 9) exercise training groups, and a control group (n = 9). Subjects in the C‐TRA group performed a continuous cycling exercise at 60% of heart rate reserve (HRR), and subjects in the I‐TRA group performed a cycling exercise consisting of alternating 2‐min intervals at 40% HRR and 80% HRR. Training programs were performed for 40 min/day, 3 days/week for 8 weeks. Before and after training, limb volume in the calf and forearm was measured with subjects in the supine position by venous occlusion plethysmography using a venous collecting cuff placed around the thigh and upper arm. Cuff pressure was held at 60 mmHg for 8 min and then decreased to 0 mmHg at a rate of 1 mmHg/s. Venous compliance was calculated as the numerical derivative of the cuff pressure–limb volume curve. Calf venous compliance was increased after I‐TRA, but not C‐TRA. Forearm venous compliance was unchanged after C‐TRA or I‐TRA. These results suggest that the adaptation of venous compliance in response to endurance training for 8 week may occur in interval but not continuous exercise bouts and may be specific to the exercising limb. This study demonstrated that 8 weeks of endurance interval exercise training, but not continuous exercise, increased calf venous compliance in young adults while forearm venous compliance remained unchanged. These findings suggest that the adaptation of venous compliance in response to short‐term endurance training could be induced by not moderate continuous exercise but interval exercise at low and high intensities, and might be specific to the exercising limb.
... This technique involves using inflatable cuffs around limbs to create vascular occlusion, thereby altering local interstitial pressures and trapping exercise-induced metabolites. BFR therapy has reported efficacy for improving performance in athletes [2,48,63,64], with growing evidence of benefits in hospitalized patients [38,65,74], including older adults [4,25,29,62]. Improvements from BFR have been found when it is used in conjunction with a variety of training modalities, such as walking [3,4,48], cycling [1], low-load resistance training [29,61,62], and body-weight exercises [26]. ...
... Of the evidence available, systematic reviews of BFR safety indicate it is not associated with additional cardiovascular stresses or morbidity [10,23,36,50]. Rather, the acute and local elevated blood pressure responses to BFR result in a variety of positive cardiovascular adaptations such as improved vascular endothelial function, peripheral blood circulation [58], and arterial and venous compliance [25,46]. Plausible mechanisms underlying BFR's ability to induce muscle hypertrophy and/or protect from muscle atrophy include biochemical responses influencing accelerated muscle hypertrophy [16,17,21,30,32,53,62,63] and enhanced muscle performance because of oxygen-dependent shifts in fiber type recruitment [63,65,66]. ...
Article
Background: Blood flow restriction (BFR) is a process of using inflatable cuffs to create vascular occlusion within a limb during exercise. The technique can stimulate muscle hypertrophy and improve physical function; however, most of these studies have enrolled healthy, young men with a focus on athletic performance. Furthermore, much of the information on BFR comes from studies with small samples sizes, limited follow-up time, and varied research designs resulting in greater design, selection, and sampling bias. Despite these limitations, BFR's popularity is increasing as a clinical rehabilitation tool for aging patients. It is important for practitioners to have a clear understanding of the reported effects of BFR specifically in older adults while simultaneously critically evaluating the available literature before deciding to employ the technique. Questions/purposes: (1) Does BFR induce skeletal muscle hypertrophy in adults older than 50 years of age? (2) Does BFR improve muscle strength and/or physical function in adults older than 50 years? Methods: Using PubMed, Google Scholar, Web of Science, and Science Direct, we conducted a systematic review of articles using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to assess the reported effects of BFR on skeletal muscle in older adults. Included articles enrolled participants 50 years of age or older and used BFR in conjunction with exercise to study the effects of BFR on musculoskeletal outcomes and functionality. The following search terms were used: "blood flow restriction" OR "KAATSU" OR "ischemic training" AND "clinical" AND "elderly." After duplicates were removed, 1574 articles were reviewed for eligibility, and 30 articles were retained with interventions duration ranging from cross-sectional to 16 weeks. Sample sizes ranged from 6 to 56 participants, and exercise tasks included passive mobilization or electrical stimulation; walking; resistance training using machines, free weights, body weight, or elastic bands; and water-based activities. Furthermore, healthy participants and those with cardiovascular disease, osteoarthritis, osteoporosis, sporadic inclusion body myositis, spinal cord injuries, and current coma patients were studied. Lastly, retained articles were assigned a risk of bias score using aspects of the Risk of Bias in Nonrandomized Studies of Interventions and the Cochrane Collaboration's tool for assessing the risk of bias in randomized trials. Results: BFR, in combination with a variety of exercises, was found to result in muscle hypertrophy as measured by muscle cross-sectional area, thickness, volume, mass, or circumference. Effect sizes for BFR's ability to induce muscle hypertrophy were calculated for 16 of the 30 papers and averaged 0.75. BFR was also shown to improve muscle strength and functional performance. Effect sizes were calculated for 21 of the 30 papers averaging 1.15. Conclusions: Available evidence suggests BFR may demonstrate utility in aiding rehabilitation efforts in adults older than 50 years of age, especially for inducing muscle hypertrophy, combating muscle atrophy, increasing muscle strength, and improving muscle function. However, most studies in this systematic review were at moderate or high risk of bias; that being so, the findings in this systematic review should be confirmed, ideally using greater sample sizes, randomization of participants, and extended follow-up durations. Level of evidence: Level II, systematic review.
... These effects may further contribute to performance improvements through enhancement of aerobic capacity and endurance by promoting angiogenesis. Moreover, BFR training is purported to provide health benefits to the elderly (2,62,67,195,215), as well as individuals afflicted by certain disease states (e.g., cardiovas-cular disease, in which it has been used to assess the suitability of BFR during cardiac rehabilitation in patients with ischemic heart disease) (106). Although BFR (or Kaatsu) training was developed in the mid-nineties in Japan (166), its worldwide use among bodybuilders and athletes is a relatively recent phenomenon. ...
... As with HTN and HF, prescribed exercise is one of the primary treatments for individuals with this disease. BFR exercise has been proposed to be beneficial in the elderly to combat age-related loss of muscle mass and strength (2,62,67,195,215) and, potentially, could likewise be used to treat PAD. However, muscle metaboreflex-induced sympathetic responses are exaggerated during mild-intensity exercise in PAD, in the absence of BFR (89,91,130,192). ...
Article
The muscle metaboreflex and arterial baroreflex regulate arterial pressure through distinct mechanisms. During submaximal exercise muscle metaboreflex activation (MMA) elicits a pressor response virtually solely by increasing cardiac output (CO) while baroreceptor unloading increases mean arterial pressure (MAP) primarily through peripheral vasoconstriction. The interaction between the two reflexes when activated simultaneously has not been well established. We activated the muscle metaboreflex in chronically instrumented canines during dynamic exercise (via graded reductions in hindlimb blood flow; HLBF) followed by simultaneous baroreceptor unloading (via bilateral carotid occlusion; BCO). We hypothesized that simultaneous activation of both reflexes would result in an exacerbated pressor response owing to both an increase in CO and vasoconstriction. We observed that coactivation of muscle metaboreflex and arterial baroreflex resulted in additive interaction although the mechanisms for the pressor response were different. MMA increased MAP via increases in CO, heart rate (HR) and ventricular contractility whereas baroreflex unloading during MMA caused further increases in MAP via a large decrease in non-ischemic vascular conductance (NIVC; conductance of all vascular beds except the hindlimb vasculature) indicating substantial peripheral vasoconstriction. Moreover, there was significant vasoconstriction within the ischemic muscle itself during coactivation of the two reflexes but the remaining vasculature vasoconstricted to a greater extent, thereby redirecting blood flow to the ischemic muscle. We conclude that baroreceptor unloading during MMA induces preferential peripheral vasoconstriction to improve blood flow to the ischemic active skeletal muscle.
... Other researchers have also reported that decline in venous compliance can be improved by ROM, strength, and endurance exercises and by compression therapy. 2,6,7 ROM exercises and isometric and isotonic strengthening exercises for the ankle muscles are the exercises that can be recommended. 8 In the literature, ROM exercises and isometric strengthening exercises have been applied to patients, and significant results were obtained. ...
... 1,2,4,17,18 As it is shown in various researches, calf muscle strength and endurance are lower in patients with CVI. 6,19 Changes in muscle structure can be shown both morphologically and pathophysiologically. Investigations performed on muscle biopsies of CVI patients have shown type 2 myofibrillary atrophy in the gastrocnemius muscle, muscle necrosis, regeneration, denervation, ischemic muscle cells denaturation, inflammatory cell proliferation, and interfascicular vein dilatation damage. 18,20 Muscle performance is traditionally evaluated by manual muscle testing. ...
Article
Full-text available
Objective The aim of this study was to observe the change of the ankle joint range of motion, the muscle strength values measured with an isokinetic dynamometer, pain scores, quality of life scale, and venous return time in chronic venous insufficiency diagnosed patients by prospective follow-up after 12-week exercise program including isokinetic exercises. Methods The patient group of this study comprised 27 patients (23 female, 4 male) who were diagnosed with chronic venous insufficiency. An exercise program including isokinetic exercise for the calf muscle was given to patients three days per week for 12 weeks. At the end of 12 weeks, five of the patients left the study due to inadequate compliance with the exercise program. As a result, control data of 22 patients were included. Ankle joint range of active motion, isokinetic muscle strength, pain, quality of life, and photoplethysmography measurements were assessed before starting and after the exercise program. Results Evaluating changes of the starting and control data depending on time showed that all isokinetic muscle strength measurement parameters, range of motion, and overall quality of life values of patients improved. Venous return time values have also increased significantly ( p < 0.05). Conclusion In conclusion, increase in muscle strength has been provided with exercise therapy in patients with chronic venous insufficiency. It has been determined that the increase in muscle strength affected the venous pump and this ensured improvement in venous function and range of motion of the ankle. In addition, it has been detected that pain reduced and quality of life improved after the exercise program.
... The studies that combined walking exercise with BFR showed positive effects on venous and arterial compliance in the elderly people with low level of physical activity [14,22]. ...
... The studies with aerobic exercise enhanced limb venous and carotid arterial compliance in sedentary elders [14,22]. However, in Ozaki's study, the increase in carotid arterial compliance was similar in the walking with and without BFR groups (without -pre: 0.079 mm 2 / mmHg, post: 0.114 mm 2 /mmHg P < 0.01 and with BFR pre: 0.084 mm 2 / mmHg, post: 0.118 mm 2 /mmHg -P < 0.01) (29). ...
Article
Full-text available
Background: Blood flow restriction (BFR) exercise has been used to induce skeletal muscle and aerobic adaptations that are similar to those induced by high intensity training, but with less time and lower intensities. The lower time demand and exercise intensity appear advantageous, especially for older people but there may be risks associated with a potential impairment of vascular function after BFR trainings. Therefore, the purpose of this systematic review was to evaluate the effects of aerobic and resistance exercise with BFR on vascular function in the elderly.
... [18][19][20] Notably, the application of blood flow restriction in combination with either low-load resistance training or aerobicbased exercises has emerged in recent years as a promising method to enhance physical fitness, especially for individuals who should not perform highly demanding exercises. [21][22][23][24][25][26] The application of blood flow restriction alone has also been recommended for people who are unable to perform any physical effort (e.g., bed rest, cast immobilization, or space flight) to reduce muscular weakness and minimize the loss of muscle mass. 27,28 Blood flow restriction consists of the application of a wrapping device (blood pressure cuff ) that restricts blood flow to the main muscles involved in the exercise and can be applied to the upper or lower extremities using different cuff pressures. ...
... 22 The importance of the present outcomes lies in the fact that blood flow restriction training has proven to induce improvements in several variables related to physical fitness of similar magnitude than traditional resistance or endurance training in which high intensities are generally applied. [21][22][23][24][25][26] Therefore, it is plausible that the application of blood flow restriction in combination with low-intensity resistance or endurance exercises could be beneficial for glaucoma patients or those at risk because they could improve physical fitness without the need of exercising at high intensities that have shown to cause acute increases in IOP. 18,20,43,44 However, future studies should be conducted to test this hypothesis because the present study has shown that the application of blood flow restriction in isolation does not meaningfully affect IOP or ocular perfusion pressure, with the exception of the use of blood flow restriction in the arms at high intensity that promoted an increase in IOP and a reduction in ocular perfusion in men. ...
Article
Significance: The use of blood flow restriction allows to obtain beneficial physical adaptions when combined with low-intensity exercise, or even when used alone. We found that using blood flow restriction may be a potential strategy to avoid intraocular pressure and ocular perfusion pressure fluctuations provoked by strength and endurance training. Purpose: To assess the influence of bilateral blood flow restriction in the upper and lower body at two different intensities on intraocular pressure and ocular perfusion pressure, as well as the possible sex differences. Methods: Twenty-eight physically active university students (14 men and 14 women) took part in the study, and blood flow restriction was bilaterally applied with two pressures in the legs and arms. There were five experimental conditions (control, legs-high, legs-low, arms-high, and arms-low). Intraocular pressure was measured by rebound tonometry before, during (every 4 s), and immediately following blood flow restriction. Ocular perfusion pressure was measured before and after blood flow restriction. Results: We found that only the arms-high condition promoted a statistically significant intraocular pressure rise when compared with the rest of the experimental conditions (all Bayes Factors10 >100, and effect sizes=1.18, 1.06, 1.35, and 1.73 for the control, arms-low, legs-high, and legs-low conditions, respectively). For ocular perfusion pressure, there was strong evidence for the null hypothesis regarding the type of blood flow restriction (Bayes Factor10=0.012); however, men showed an ocular perfusion pressure reduction following blood flow restriction in the arms-high condition (Bayes Factor10=203.24, effect size=1.41). Conclusions: This study presents preliminary evidence regarding the safety of blood flow restriction in terms of ocular health. Blood flow restriction may be considered as an alternative training strategy to reduce abrupt fluctuations in intraocular pressure and ocular perfusion pressure, since its use permits a considerable reduction of exercise intensity.
... Most studies have examined muscle hypertrophy and strength adaptations over time frames >3 weeks duration (Burgomaster et al., 2003;Moore et al., 2004;Abe et al., 2006;Iida et al., 2011;Nielsen et al., 2012;Yasuda et al., 2012;Martín-Hernández et al., 2013;Luebbers et al., 2014;Kang et al., 2015). ...
... Other forms of application of the BFR stimulus have received less attention in the literature. BFR-AE has acutely shown to impair flow mediated dilatation (FMD) (Renzi et al., 2010), whilst others have reported BFR-AE to increase FMD in the long term (Iida et al., 2011). ...
Article
Full-text available
The current manuscript sets out a position stand for blood flow restriction exercise, focusing on the methodology, application and safety of this mode of training. With the emergence of this technique and the wide variety of applications within the literature, the aim of this position stand is to set out a current research informed guide to blood flow restriction training to practitioners. This covers the use of blood flow restriction to enhance muscular strength and hypertrophy via training with resistance and aerobic exercise and preventing muscle atrophy using the technique passively. The authorship team for this article was selected from the researchers focused in blood flow restriction training research with expertise in exercise science, strength and conditioning and sports medicine.
... This section on mechanisms has largely focused on the potential mechanisms of action for muscular adaptations with BFRT, as the increases in muscular strength and hypertrophy are of relevance in the rehabilitation setting and may directly correlate to tendon adaptations, which are discussed in a later section. However, various other systemic and physiological systems responses have been shown with BFRT including positive effects on cardiopulmonary function (Moriggi et al., 2015), vascular stiffness and compliance (Renzi et al., 2010;Iida et al., 2011;Sugawara et al., 2015), bone function (Karabulut et al., 2011), psychological function (Lixandrao et al., 2019;Silva et al., 2018;da Silva et al., 2019;Mattocks et al., 2019), musculoskeletal function (Bowman et al., 2019), neural function , and anaerobic and aerobic exercise capacity (Mendonca et al., 2015;Tanaka et al., 2018). A full discussion of the potential mechanisms involved in BFRT are beyond the scope of this review, and readers are directed to other reviews for a more focused analysis of BFRT mechanisms (Pearson and Hussain, 2015). ...
... The evergrowing body of evidence includes RCT evidence of potential efficacy for a plethora of musculoskeletal conditions including, polymyositis and dermatomyositis(Mattar et al., 2014), osteoarthritis Femandes- Bryk et al., 2016; Ferraz et al., 2018; Harper et al., 2019;Shakeel et al., 2021), pre and post-operative ACL reconstruction(Ohta et al., 2003;Iversen et al., 2016; Curran et al., 2020;Takarada et al., 2000; Lambert et al., 2019;Kilgas et al., 2019;Zargi et al., 2018; Grapar Zargi et al., 2016), patellofemoral pain(Giles et al., 2017; Constantinou et al., 2022;Ladlow et al., 2018), post knee arthroscopy(Tennent et al., 2017), rheumatoid arthritis(Jonsson et al., 2020;Rodrigues et al., 2020), osteoporosis(Pereira Neto et al., 2018), osteopenia (Linero and Choi, 2021), and muscle atrophy(Noyes et al., 2021;Lipker et al., 2019). Many RCTs have also found benefits of BFRT in elderly populations at risk for sarcopenia and other medical and musculoskeletal disorders(Yokokawa et al., 2008;Karabulut et al., 2013; Karabulut et al., 2010;Patterson and Ferguson, 2011; Ozaki et al., 2011; Ozaki et al., 2011;Iida et al., 2011; Yasuda et al., 2015;Vechin et al., 2015;Libardi et al., 2015; Shimizu et al., 2016;Thiebaud et al., 2013; Clarkson et al., 2017; Fahs et al., 2015; Araujo et al., 2015;Letieri et al., 2018). Preliminary evidence from non-RCT study designs have indicated potential efficacy of LL-BFRT for ankle sprains(Krieger et al., 2018;Hylden et al., 2015), ankle fractures(Larsen et al., 2021), shoulder injuries(Lambert et al., 2021), reactive arthritis(Jorgensen et al., 2021), thoracic outlet syndrome(Noto et al., 2017), inclusion body myositis(Santos et al., 2014), knee arthroplasty(Gaunder et al., 2017), tibial fractures, meniscus repair ...
Preprint
Full-text available
Tendinopathy is chronic tendon disease which can cause significant pain and functional limitations for individuals and collectively place a tremendous burden on society. Resistance training has long been considered the treatment of choice in the rehabilitation of chronic tendinopathies, with both eccentric and heavy slow resistance training demonstrating positive clinical effects. The application of progressive tendon loads during rehabilitation is essential to not compromise tendon healing, with the precise dosing parameters of resistance training and external loading a critical consideration. Blood-flow restriction training (BFRT) has become an increasingly popular method of resistance training in recent years and has been shown to be an effective method for enhancing muscle strength and hypertrophy in healthy populations and in musculoskeletal rehabilitation. Traditional resistance training for tendinopathy requires the application of heavy training loads, whereas BFRT utilises significantly lower loads and training intensities, which may be more appropriate for certain clinical populations. Despite evidence confirming the positive muscular adaptations derived from BFRT and the clinical benefits found for other musculoskeletal conditions, BFRT has received a dearth of attention in tendon rehabilitation. Therefore, the purpose of this narrative review was threefold: firstly, to give an overview and analysis of the mechanisms and outcomes of BFRT in both healthy populations and in musculoskeletal rehabilitation. Secondly, to give an overview of the evidence to date on the effects of BFRT on healthy tendon properties and clinical outcomes when applied to tendon pathology. Finally, a discussion on the clinical utility of BFRT and its potential applications within tendinopathy rehabilitation, including as a compliment to traditional heavy-load training, will be presented.
... It has also been found that exercises with low BFR load can act on bone metabolism; thus, they could have an effect on the control of osteoporosis (29). In addition, plethysmography has shown that a 6-week BFR walking program can improve limb venous compliance (30). ...
... Interestingly, a recent meta-analysis by Slysz et al. showed that the strength adaptations occur in an intensitydependent manner, with higher walking intensities (> 70 m/ min) eliciting greater strength increases compared with lower intensities (< 70 m/min) [1]. Besides its positive effects on muscle mass and strength, walking combined with BFR has also been shown to improve venous compliance in untrained elderly subjects [68]. ...
... [14][15][16] This technique has been successfully and safely used in athletes to improve performance and in the elderly to improve strength and function. 10,[17][18][19][20][21][22][23][24] The purpose of this study was to evaluate the addition of BFR-based exercise to traditional methods of physical therapy to improve strength, hypertrophy, functional outcomes, and patient self-reported outcomes after postoperative nonreconstructive knee arthroscopy. ...
... Among numerous benefits resulting from the influence of NW on health, there is a lack of data related to the influence of this kind of activity on the blood flow in venous vessels of lower extremities. The study of Iida et al. (2011) proves that slow walking on a treadmill may increase the blood flow in lower extremities of older women. In subjects with a limited blood flow in lower extremities, slow walking causes muscle hypertrophy and improves muscle strength despite a minimum level of exercise intensity (Abe et al., 2006). ...
Article
Full-text available
Nordic walking and water aerobics are very popular forms of physical activity in the elderly population. The aim of the study was to evaluate the influence of regular health training on the venous blood flow in lower extremities and body composition in women over 50 years old. Twenty-four women of mean age 57.9 (± 3.43) years, randomly divided into three groups (Nordic walking, water aerobics, and non-training), participated in the study. The training lasted 8 weeks, with one-hour sessions twice a week. Dietary habits were not changed. Before and after training vein refilling time and the function of the venous pump of the lower extremities were measured by photoplethysmography. Body composition was determined by bioelectrical impedance. Eight weeks of Nordic walking training improved the venous blood flow in lower extremities and normalized body composition in the direction of reducing chronic venous disorder risk factors. The average values of the refilling time variable (p = 0.04, p = 0.02, respectively) decreased in both the right and the left leg. After training a statistically significant increase in the venous pump function index was found only in the right leg (p = 0.04). A significant increase in fat-free mass, body cell mass and total body water was observed (p = 0.01), whereas body mass, the body mass index, and body fat decreased (p < 0.03). With regard to water aerobic training, no similar changes in the functions of the venous system or body composition were observed.
... Venous stiffness as well as arterial stiffness has been reported to increase with aging, and we studied the effects of kaatsu-walk training by elderly individuals on venous stiffness. In the results, we reported that kaatsu-walk training by elderly individuals also improved venous stiffness 34) . This series of results suggests that in kaatsu-walk training, an effect of increased muscle size is observed even among elderly individuals only with low intensity loads at which conventional training does not produce such an effect, and likewise, that vascular compliance may be improved, and that progression of arteriosclerosis may be prevented. ...
Article
Full-text available
As demographic aging continues in Japan, the number of very elderly individuals aged 75 years or older is increasing rapidly, as is the number of bedridden, elderly individuals, with ramifications extending to economic problems such as health care costs and insurance for long-term care. Consequently, there is a great importance to questions of how to prevent age-related loss of muscle (sarcopenia) to prevent bedridden states, and further to improve quality of life (QOL) and maintain active lifestyles. Exercise is the most effective means for preventing and addressing sarcopenia. Regular exercise is also reported to prevent progression of arteriosclerosis, prevent lifestyle diseases, and delay onset of dementia. However, the effects of exercise are known to differ substantially for different types of exercise. Regular walking and other aerobic exercise improves cardiovascular endurance, but among the elderly, loss of muscular strength, muscular atrophy, and other diminished physical functions have implications for falling and fractures, and it is not uncommon to see a consequent aggravation of disuse syndrome due to inactivity, leading to a bedridden state. In this light, strength training is also important for elderly individuals, to increase muscular strength and muscle mass. It is also highly important for elderly individuals to eat a diet, particularly amino acids, that enhances the effects of exercise. Here we present an overview of aerobic exercise, resistance training, and “kaatsu training” ( i.e., training under pressure-restricted blood flow to the extremities) representing anti-aging exercise methods. We likewise discuss the importance of diet for exercise.
... carotid artery compliance; carotid-femoral pulse wave velocity; plasma vasoconstrictor hormones; carotid artery vasoreactivity; muscle strength and total lean mass in both protocols. increased leg venous compliance and maximal venous outflow, demonstrating for the first time that 6 weeks of walking exercise with blood flow restriction may improve limb venous compliance in untrained elderly female subjects [112]. Many elderly adults may not have the muscular strength or exercise tolerance to train at intensities required to improve compliance, and thus KAATSU training that requires very low intensities may be a viable alternative. ...
Article
Full-text available
Background: Aging and low physical activity are associated with the development of diseases (hypertension, type 2 diabetes, dyslipidemia, obesity) marked by chronic low-grade inflammation. Cardiovascular disease is the most common cause of death worldwide, while exercising muscle tissue can increase the secretion of myokines that can reestablish a possible inflammatory process in virtue of the anti-inflammatory effect. Methods: The objective of this review is to focus on molecular mechanisms involved between different kinds of exercise and cellular oxidative stress, and the emerging therapeutic strategies which have the potential to promote benefits in vascular health. Results: Regular exercise increases shear stress, mitochondrial biogenesis, and upregulates mitochondrial antioxidant system, inducing anti-inflammatory actions, such as suppression of TNF-α which may offer protection against TNF-α-induced vascular impairment. Conclusion: Exercise training of various durations and intensities appears to prevent and restore the age-related impairment of endothelial function, likely through the restoration of NO availability, reduction in oxidative stress, and turnover of the apoptotic process in the endothelium, thus minimizing vascular inflammation and decreasing the formation of atherosclerotic plaques.
... ЛФК рекомендуется для устранения проблемы дисфункции мышечной помпы [418,419]. Повышение тонуса вен можно достигнуть с помощью силовых упражнений для укрепления мышц голени и упражнений на выносливость [407,[419][420][421]. Установлено, что изометрические и изотонические упражнения для укрепления мышц голени у пациентов с венозными язвами обусловливают увеличение мышечной силы венозной помпы и AROM, что в свою очередь способствует уменьшению амбулаторной венозной гипертензии [422,423]. ...
... [14][15][16] This technique has been successfully and safely used in athletes to improve performance and in the elderly to improve strength and function. 10,[17][18][19][20][21][22][23][24] The purpose of this study was to evaluate the addition of BFR-based exercise to traditional methods of physical therapy to improve strength, hypertrophy, functional outcomes, and patient self-reported outcomes after postoperative nonreconstructive knee arthroscopy. ...
Article
Full-text available
Introduction: Quadriceps strength after arthroscopic knee procedures is frequently diminished several years postoperation. Blood flow restriction (BFR) training uses partial venous occlusion while performing submaximal exercise to induce muscle hypertrophy and strength improvements. The purpose of this study was to evaluate BFR as a postoperative therapeutic intervention after knee arthroscopy. Methods: A randomized controlled pilot study comparing physical therapy with and without BFR after knee arthroscopy was conducted. Patients underwent 12 sessions of supervised physical therapy. Subjects followed the same postoperative protocol with the addition of 3 additional BFR exercises. Outcome measures included thigh girth, physical function measures, Knee Osteoarthritis Outcome Score (KOOS), Veterans RAND 12-Item Health Survey (VR12), and strength testing. Bilateral duplex ultrasonography was used to evaluate for deep venous thrombosis preintervention and postintervention. Results: Seventeen patients completed the study. Significant increases in thigh girth were observed in the BFR group at 6-cm and 16-cm proximal to the patella (P = 0.0111 and 0.0001). All physical outcome measures significantly improved in the BFR group, and the timed stair ascent improvements were greater than conventional therapy (P = 0.0281). The VR-12 and KOOS subscales significantly improved in the BFR group, and greater improvement was seen in VR-12 mental component score (P = 0.0149). The BFR group displayed approximately 2-fold greater improvements in extension and flexion strength compared with conventional therapy (74.59% vs 33.5%, P = 0.034). No adverse events were observed during the study. Conclusions: This study suggests that BFR is an effective intervention after knee arthroscopy. Further investigation is warranted to elucidate the benefits of this intervention in populations with greater initial impairment.
... R: The reviewer has an interesting point. In fact, initially the prescription of BFR-RE was aimed to populations unable to perform high intensity resistance exercise (FRY et al., 2010; GUALANO, NEVES et al., 2010; GUALANO, UGRINOWITSCH et al., 2010; IIDA et al., 2011; RENZI et al., 2011; LOENNEKE et al., 2012; SILVA-BATISTA et al., 2014; LIBARDI et al., 2015). However, currently, this method has become increasingly popular among novice individuals in resistance training ...
Article
The aim of the present study was to compare hemodynamic responses between blood flow-restricted resistance exercise (BFR-RE), high-intensity resistance exercise (HI-RE) and low-intensity resistance exercise (LI-RE) performed to muscular failure. 12 men (age: 20±3 years; body mass: 73.5±9 kg; height: 174±6 cm) performed 4 sets of leg press exercises using BFR-RE (30% of 1-RM), HI-RE (80% of 1-RM) and LI-RE (30% of 1-RM) protocols. Systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR), stroke volume (SV), cardiac output (CO) and total peripheral vascular resistance (TPR) were measured on a beat-to-beat continuous basis by a noninvasive photoplethysmographic arterial pressure device. The HI-RE and LI-RE showed higher values (P<0.05) in all of the sets than the BFR-RE for SBP, DBP, HR. Additionally, HI-RE showed higher SBP (4(th) set) and DBP (all sets) (P<0.05) values than the LI-RE. However, the SV, CO and TPR showed significantly greater values for LI-RE compared to HI-RE and BFR-RE (P<0.05). In conclusion, the results of this study indicate that the BFR-RE promotes a lower hemodynamic response compared to the HI-RE and LI-RE performed to muscular failure.
... O treinamento de força (TF) de baixa carga com restrição de fluxo sanguíneo (RFS) surgiu como uma alternativa ao treino tradicional de alta intensidade (Sato, 2005). As pesquisas mostram sua eficácia sobre variáveis neuromusculares, como os ganhos de força e hipertrofia muscular (Pearson & Hussain, 2015), hormonais (Inagaki, Madarame, Neya, & Ishii, 2011), metabólicas (Burgomaster et al., 2003;Fujita et al., 2007), hemodinâmicas (Araújo et al., 2014;Brandner, Kidgell, & Warmington, 2014;Neto et al., 2015;Neto et al., 2016;Okuno, Pedro, Leicht, Ramos, & Nakamura, 2014;Rossow et al., 2011;Vieira, Chiappa, Umpierre, Stein, & Ribeiro, 2013) e complacência arterial (Iida et al., 2011;Iida et al., 2005). ...
Article
Full-text available
The aim of the present study was to verify the acute effect of the aerobic exercise (AE) with blood flow restriction (BFR) upon systolic (SBP), diastolic blood pressure (DBP) and heart rate (HR) in health youngsters. Participated in the present study 13 young normotensive students (19.5 ± 1.7 years old). The sample was randomly divided into two experimental protocols: stationary race with BFR and stationary race without BFR. Subjects performed 5 sets of 2 minutes with 1 minute of rest interval for both protocols. SBP, DBP and HR were measured at rest, in the end of the exercises and during 60 minutes after conditions. The AE without BFR presented hypotensive effect 60 minutes post exercise (p= 0.029); the AE with and without BFR elevated significantly the SBP and HR immediately post exercise (p< 0.05) and the AE with BFR presented higher DBP and HR values immediately post-exercise when compared to AE without BFR (p= 0.001; p< 0.001, respectively). It is concluded that the AE without BFR does not seem to maximize the hypotensive effect, both sessions can increase SBP and HR immediately post-exercise with significant higher values in DBP and HR for AE with BFR.
... It may also be valuable to include measures related to vascular stiffness (e.g. pulse wave velocity and vascular-related microRNAs), as this has also been shown to improve with exercise training, and may be enhanced with the addition of blood flow restriction [34,70,71]. ...
Article
Full-text available
Background Exercise during haemodialysis improves strength and physical function. However, both patients and clinicians are time poor, and current exercise recommendations add an excessive time burden making exercise a rare addition to standard care. Hypothetically, blood flow restriction exercise performed during haemodialysis can provide greater value for time spent exercising, reducing this time burden while producing similar or greater outcomes. This study will explore the efficacy of blood flow restriction exercise for enhancing strength and physical function among haemodialysis patients. Methods This is a randomised controlled trial design. A total of 75 participants will be recruited from haemodialysis clinics. Participants will be allocated to a blood flow restriction cycling group, traditional cycling group or usual care control group. Both exercising groups will complete 3 months of cycling exercise, performed intradialytically, three times per week. The blood flow restriction cycling group will complete two 10-min cycling bouts separated by a 20-min rest at a subjective effort of 15 on a 6 to 20 rating scale. This will be done with pressurised cuffs fitted proximally on the active limbs during exercise at 50% of a pre-determined limb occlusion pressure. The traditional cycling group will perform a continuous 20-min bout of exercise at a subjective effort of 12 on the same subjective effort scale. These workloads and volumes are equivalent and allow for comparison of a common blood flow restriction aerobic exercise prescription and a traditional aerobic exercise prescription. The primary outcome measures are lower limb strength, assessed by a three repetition maximum leg extension test, as well as objective measures of physical function: six-minute walk test, 30-s sit to stand, and timed up and go. Secondary outcome measures include thigh muscle cross sectional area, body composition, routine pathology, quality of life, and physical activity engagement. Discussion This study will determine the efficacy of blood flow restriction exercise among dialysis patients for improving key physiological outcomes that impact independence and quality of life, with reduced burden on patients. This may have broader implications for other clinical populations with similarly declining muscle health and physical function, and those contraindicated to higher intensities of exercise. Trial registration Australian and New Zealand Clinical Trial Register: ACTRN12616000121460.
... Both nutrient and exercise could play an important role in the improvement and maintenance of vascular health. Indeed, habitual endurance exercise is known to increase venous compliance [1,2,[11][12][13]. However, little is known about the effect of diet on venous compliance. ...
Article
Full-text available
Background: Venous compliance decreases with aging and/or physical inactivity, which is thought to be involved partly in the pathogenesis of cardiovascular disease such as hypertension. This suggests that it is important to maintain high venous compliance from a young age in order to prevent cardiovascular disease. Both nutrient and exercise could play an important role in the improvement and maintenance of vascular health. Indeed, habitual endurance exercise is known to improve the venous compliance, although little is known about the effect of diet on venous compliance. Considering that higher consumption of vegetables could contribute to the arterial vascular health and the decreased blood pressure, it is hypothesized that venous compliance may be greater as vegetable intake is higher. Thus, the purpose of this study was to clarify the association between vegetable intake and venous compliance in healthy young adults. Methods: Dietary intake was assessed in 94 subjects (male: n = 44, female: n = 50) using a self-administered diet history questionnaire (DHQ). Intakes of nutrients and food groups that were obtained from the DHQ were adjusted according to total energy intake using the residual method. Based on the adjusted intake of food groups, total vegetable intake was calculated as the sum of green/yellow and white vegetables consumed. Calf volume was measured using venous occlusion plethysmography with a cuff deflation protocol. Calf venous compliance was calculated as the numerical derivative of the cuff pressure-calf volume curve. In addition, circulatory responses (heart rate and systolic and diastolic blood pressure) at resting and maximal oxygen uptake were assessed in all subjects. Results: Mean value of total vegetables intake was 162.2 ± 98.2 g/day. Simple linear regression analysis showed that greater venous compliance was significantly associated with higher total vegetable consumption (r = 0.260, P = 0.011) and green/yellow vegetable intake (r = 0.351, P = 0.001) but not white vegetable intake (r = 0.013, P = 0.902). These significant associations did not change in the multivariate linear regression models which were adjusted by sex and maximal oxygen uptake. Conclusion: These findings suggest that higher consumption of vegetables, especially of the green/yellow vegetables, may be associated with greater venous compliance in young healthy adults.
... Interestingly, a recent meta-analysis by Slysz et al. showed that the strength adaptations occur in an intensitydependent manner, with higher walking intensities (> 70 m/ min) eliciting greater strength increases compared with lower intensities (< 70 m/min) [1]. Besides its positive effects on muscle mass and strength, walking combined with BFR has also been shown to improve venous compliance in untrained elderly subjects [68]. ...
Article
Full-text available
Background The combination of low-load resistance training with blood flow restriction (BFR) has recently been shown to promote muscular adaptations in various populations. To date, however, evidence is sparse on how this training regimen influences muscle mass and strength in older adults. Purpose The purpose of this systematic review and meta-analysis was to quantitatively identify the effects of low-load BFR (LL-BFR) training on muscle mass and strength in older individuals in comparison with conventional resistance training programmes. Additionally, the effectiveness of walking with and without BFR was assessed. Methods A PRISMA-compliant systematic review and meta-analysis was conducted. The systematic literature research was performed in the following electronic databases from inception to 1 June 2018: PubMed, Web of Science, Scopus, CINAHL, SPORTDiscus and CENTRAL. Subsequently, a random-effects meta-analysis with inverse variance weighting was conducted. Results A total of 2658 articles were screened, and 11 studies with a total population of N = 238 were included in the meta-analysis. Our results revealed that during both low-load training and walking, the addition of BFR elicits significantly greater improvements in muscular strength with pooled effect sizes (ES) of 2.16 (95% CI 1.61 to 2.70) and 3.09 (95% CI 2.04 to 4.14), respectively. Muscle mass was also increased when comparing walking with and without BFR [ES 1.82 (95% CI 1.32 to 2.32)]. In comparison with high-load training, LL-BFR promotes similar muscle hypertrophy [ES 0.21 (95% CI − 0.14 to 0.56)] but lower strength gains [ES − 0.42 (95% CI − 0.70 to − 0.14)]. Conclusion This systematic review and meta-analysis reveals that LL-BFR and walking with BFR is an effective interventional approach to stimulate muscle hypertrophy and strength gains in older populations. As BFR literature is still scarce with regard to potential moderator variables (e.g. sex, cuff pressure or training volume/frequency), further research is needed for strengthening the evidence for an effective application of LL-BFR training in older people.
... Low-load RT combined with BFR is also effective for the prevention of muscle loss and weakness after 30 days of unilateral lower limb suspension (Cook et al., 2010). BFR combined with light AET (walking, cycling) improves vascular compliance in the elderly (Iida et al., 2011;Ozaki et al., 2011), which is an important finding because this variable markedly decreases with ageing or bed rest (Bleeker et al., 2004). In addition, it improves muscle size, strength and functional ability to a greater extent than a higher volume of AET without BFR . ...
... BFR combined with light AET (e.g., walking) improves muscle size, strength, and functional ability in elderly people (3) and also enhances vascular compliance in this population (129,208), which markedly decreases with aging and/or bed rest (27). Thus, although more evidence is needed regarding its effects in the oldest old, BFR in conjunction with low-intensity exercise training (AET or RET) is an effective strategy for attenuating muscle wasting and functional ability in those situations in which high-intensity exercise is not feasible. ...
Article
Societies are progressively aging, with the oldest old (i.e., those aged >80–85 years) being the most rapidly expanding population segment. However, advanced aging comes at a price, as it is associated with an increased incidence of the so‐called age‐related conditions, including a greater risk for loss of functional independence. How to combat sarcopenia, frailty, and overall intrinsic capacity decline in the elderly is a major challenge for modern medicine, and exercise appears to be a potential solution. In this article, we first summarize the physiological mechanisms underlying the age‐related deterioration in intrinsic capacity, particularly regarding those phenotypes related to functional decline. The main methods available for the physical assessment of the oldest old are then described, and finally the multisystem benefits that exercise (or “exercise mimetics” in those situations in which volitional exercise is not feasible) can provide to this population segment are reviewed. In summary, lifetime physical exercise can help to attenuate the loss of many of the properties affected by aging, especially when the latter is accompanied by an inactive lifestyle and benefits can also be obtained in frail individuals who start exercising at an advanced age. Multicomponent programs combining mainly aerobic and resistance training should be included in the oldest old, particularly during disuse situations such as hospitalization. However, evidence is still needed to support the effectiveness of passive physical strategies including neuromuscular electrical stimulation or vibration for the prevention of disuse‐induced negative adaptations in those oldest old people who are unable to do physical exercise.
... In addition, there are some data about BFR during muscle wasting or aging and a case report has suggested that BFR should be considered to improve physical fitness, prevent muscle loss, and improve arterial compliance in frail aged subjects [301,302]. In old women, resistance training at low intensity combined with BFR at 110 mmHg appears effective to induce hypertrophy and gains in muscle strength [303], and walking with BFR at higher pressure improves limb venous compliance [304]. However, a study reported that a sixweek walking training with BFR did not improve peak oxygen uptake in old men and women, even if functional ability, muscle size, and strength were improved [305]. ...
Article
Full-text available
The regulation of skeletal muscle mass and organelle homeostasis is dependent on the capacity of cells to produce proteins and to recycle cytosolic portions. In this investigation, the mechanisms involved in skeletal muscle mass regulation—especially those associated with proteosynthesis and with the production of new organelles—are presented. Thus, the critical roles of mammalian/mechanistic target of rapamycin complex 1 (mTORC1) pathway and its regulators are reviewed. In addition, the importance of ribosome biogenesis, satellite cells involvement, myonuclear accretion, and some major epigenetic modifications related to protein synthesis are discussed. Furthermore, several studies conducted on the topic of exercise training have recognized the central role of both endurance and resistance exercise to reorganize sarcomeric proteins and to improve the capacity of cells to build efficient organelles. The molecular mechanisms underlying these adaptations to exercise training are presented throughout this review and practical recommendations for exercise prescription are provided. A better understanding of the aforementioned cellular pathways is essential for both healthy and sick people to avoid inefficient prescriptions and to improve muscle function with emergent strategies (e.g., hypoxic training). Finally, current limitations in the literature and further perspectives, notably on epigenetic mechanisms, are provided to encourage additional investigations on this topic.
... The results showed improvements in the CSA of arm muscles, arm strength, and cardio-ankle vascular index (CAVI) [15]. An investigation of lower extremities' venous outflow in 16 older women (68.7 ± 2.8 years) who performed a 6-week treadmill walking program five times a week versus a nonexercise control groups found increased venous blood flow in the women in the BFR group [23]. ...
Article
Full-text available
Purpose of Review Blood flow restriction (BFR) exercise is a recent and novel intervention showing promising results in counteracting several physiological effects related to aging, leading to disability in older adults. The purpose of this paper is to review recent literature within the last 5 years on the effectiveness of BFR training in older adults. Recent Findings BFR performed during light load (20–30% of one-repetition maximum) resistance exercise have showed to enhance musculoskeletal and cardiometabolic health in healthy and frail older adults without any adverse events. Other novel findings are improvements in mobility and gait after performing a BFR training intervention. Summary Including BFR simultaneously with resistance exercise increases bone and muscle mass primarily through several hormonal pathways at the same time it enhances cardiovascular function without any adverse events. The improvements in mobility and gait are indicators of greater health-related quality of life minimizing disability in older adults.
... The potential for metabolic stress to stimulate muscle hypertrophy in older adults have been demonstrated by several studies using similar BFR (~above 50% AOP or up to 20 mmHg) with resistance exercise training (~20-50% 1RM) protocol over a period of time [29,31,32,[50][51][52][53][54][55][56]67]. BFR with aerobic exercise also resulted in muscle hypertrophy in older adults [68][69][70], but to a smaller extent (~3%), compared with combined BFR resistance exercise (~4-17%). ...
Article
Full-text available
Background: Aging leads to a number of structural and physiological deficits such as loss of muscle mass and strength. Strength training at ~ 70% of 1 repetition max (RM) is recommended to prevent age-related loss of muscle mass and strength. However, most older adults may not be able to perform 70% of 1RM or higher intensity. An alternative exercise training program combining low intensity resistance exercise with blood flow restriction (BFR) can result in similar acute and chronic benefits to skeletal muscles in older adults. Main body and short conclusion: The potential mechanisms involved are discussed, and include reactive hyperaemia, metabolic stress, and hypoxia. Key issues and safety with the use of BFR in older adults, especially those with chronic conditions are also discussed. Although there has been no reported evidence to suggest that BFR elevates the risk of clinical complications any more than high intensity exercise, it is recommended for individuals to be medically cleared of any cardiovascular risks, prior to engaging in BFR exercise.
... Other research examining the venous response to BFR has been performed, primarily in the lower body. One study examined walk training while under BFR and found that calf venous compliance increased (Iida et al 2011). Another study examined calf venous compliance following knee extensor training and saw no change in compliance (Fahs et al 2014). ...
... 13 Studies conducted with older individuals have already identified increased muscle strength, 21,22 increased growth hormone (GH) secretion and functional capacity, 23 increased walking speed in patients with myositis, 24 increase in bone markers, 25 physical function in older patients with osteoarthritis, 26 and in hemodynamic aspects. 27 Also, one systematic review published recently showed that BFR training was effective in improving strength and promote muscle hypertrophy in middle-age and older adults. 28 Although muscle mass and strength have been reviewed extensively, 28-30 the functional capacity related to the physical demands imposed by daily life tasks, such as climbing upstairs and downstairs, standing up and sitting on a chair, have not been fully evidenced in review studies that use the BFR method with groups made up exclusively of older individuals. ...
Article
Aims: This systematic review with meta-analysis aimed to verify the effects of Blood Flow Restriction (BFR) on the strength, muscle mass and physical function of older individuals and compare to the exercises program with low and high load. Methods: The search was performed in the databases: Pubmed, Science Direct, Scielo, LILACS, and Google Scholar. The methodological quality of the studies was assessed using the PEDro Scale. Results: Eight studies were eligible. The strength improvement were from 2.9 to 35.6% (SMD: 0.68; CI: 0.05, 1.32; p < .05), the muscle cross-sectional area (CSA) increased from 3.1 to 8% (SMD 0.47; CI 0.11, 0.82; p < .01), and physical function from 12 to 28% (SMD: −0.15; CI −1.01, 0.70; p > .05). Conclusion: BFR training was effective for increasing strength, muscle mass and physical function in the older adults, presenting the advantage of less mechanical stress, and should be considered as an alternative when traditional training is contraindicated.
... Blood flow restriction resistance exercise induces local hypoxia by the placement of pressurized cuffs at the proximal portion of the muscle, which reduces arterial inflow and impedes venous return, thus resulting in venous pooling (Iida et al., 2011). The restrictive cuffs are commonly inflated at the beginning of the exercise bout and, then, only deflated following exercise completion, leading to BFR resistance exercise commonly resulting in considerable local discomfort (Hughes et al., 2018). ...
Article
Full-text available
The primary goal of this investigation was to examine the physiological responses of blood flow restriction (BFR) resistance exercise (RE) performed with continuous or intermittent BFR and to compare these results to those from conventional high-and low-load RE without BFR. Fourteen men randomly completed the following experimental trials: (1) low-load RE with continuous BFR (cBFR), (2) low-load RE with intermittent BFR (iBFR), (3) low-load RE without BFR (LI), and (4) conventional high-load RE without BFR (HI). For the cBFR, iBFR, and LI exercise trials, participants performed four sets of 30-15-15-15 repetitions of the bilateral leg press (LP) and knee extension (KE) exercises, at an intensity of 20% of their one-repetition maximum (1-RM), at a 1.5-s contraction speed, and with a 1-min rest period between sets. The only difference between the cBFR and iBFR protocols was that the pressure of the cuffs was released during the rest intervals between sets for the iBFR trial. For the HI trial, participants completed four sets of 10 repetitions of the same exercises, at 70% of 1-RM, with a 1-min rest period between sets, and at the same contraction speed. Muscle activity was assessed during each set using superficial electromyography, as well as changes in blood lactate concentration [La − ] from baseline at 5 min post exercise and in muscle swelling and plasma volume (% PV) at 5 and 15 min post exercise. There were no significant differences in muscle activity (p < 0.05) across the cBFR, iBFR, and LI protocols at any time point, whereas they were all significantly lower than HI. There were also no significant (p < 0.05) differences across the three low-load RE conditions for [La − ],% PV, or muscle swelling. HI elicited significantly (p < 0.05) greater responses than cBFR, iBFR, and LI for all the physiological markers measured. In conclusion, RE combined with cBFR or iBFR induce the same acute physiological responses. However, the largest physiological responses are observed with HI, probably because of the significantly greater exercise volumes. Therefore, releasing the pressure of the restrictive cuffs during the rest periods between sets will not hinder the acute physiological responses from BFR RE.
... Other research examining the venous response to BFR has been performed, primarily in the lower body. One study examined walk training while under BFR and found that calf venous compliance increased (Iida et al 2011). Another study examined calf venous compliance following knee extensor training and saw no change in compliance (Fahs et al 2014). ...
Article
Objective: To investigate vascular adaptations to eight weeks of resistance exercise, with and without different pressures of blood flow restriction (BFR), in the upper and lower body. Approach: Forty individuals (men=20, women=20) completed eight weeks of resistance exercise at very low loads (15% of one-repetition maximum (1RM)), with two levels of BFR (40% arterial occlusion pressure (AOP), 80% AOP), without BFR, and 70% of 1RM. Vascular conductance and venous compliance were measured via plethysmography before and following training in the forearms and in the calves. Main results: Values reported as means (95% confidence intervals). Pre to post changes in vascular conductance occurred only in the high pressure conditions (upper body: +8.29 (3.01-13.57) ml·mmHg-1; lower body: +7.86 (3.37-12.35) ml·mmHg-1) and high load conditions (upper body: +8.60 (3.45-13.74) ml·mmHg-1); lower body: +7.20 (2.71-11.69) ml·mmHg-1) only. In the upper body, the change was significantly greater in the high pressure and high load conditions compared to the change observed in the low pressure condition (-0.41 (-5.56, 4.73) ml·mmHg-1). These changes were not greater than the change observed in the low load condition without pressure (+1.81 (-3.47, 7.09) ml·mmHg-1). In the lower body, the change in the high pressure and high load conditions were significantly greater than the changes observed with low load training with (-0.86 (-5.60, 3.87) ml·mmHg-1) and without (-1.22 (-5.71, 3.27) ml·mmHg-1) a low pressure. Venous compliance increased in all groups in the upper body (+ 0.003 (.00008, 0.006) ml·100ml-1·mmHg-1) only, with no changes in the lower body. Significance: High pressure BFR causes adaptations in vascular function following eight weeks of training at mechanical loads not typically associated with such adaptations.
Article
Blood flow restriction training has proven to be effective, but it is not well known and is limited by initially producing discomfort. Blood flow restriction (BFR) induces hypoxia and metabolic effects, as well as reduction of proteolysis and induction of anabolic processes. Growth hormone levels are regularly increased. Controversies exist concerning neuromuscular effects. Twenty--eight of 30 studies, showed an increase in strength usually associated with muscle hypertrophy in both men and women, although data for women are sparse. Initial reports exist on positive effects on bone health after measuring rises in bone markers. A gain in strength has also been reported in non--occluded muscles after BFR training. BFR without training can lead to a rise in strength and reduce atrophy in knee extensor muscles during immobilisation. Controversial results have been observed concerning changes in aerobic capacity. Up to now no standard BFR training guidelines exist. Occlusion pressure, intensity of training, number of sets and duration of a training unit remain unclear. Presently, an occlusion pressure of 150 mmHg may be recommended with an intensity of 20 % 1--repetition maximum (1 RM), and wider cuffs are more efficient than narrow ones. Between training sets BFR should be continued. Rheologic investigations after BFR have shown no evidence for increased risk of thrombosis, when studying possible contraindications. Safety aspects for older patients must be more thoroughly addressed. The low--intensity needed may establish this training method in cardiac and pulmonary patients after future research.
Article
Objective To systematically evaluate the effect of blood flow restriction (BFR) combined with low-intensity (LI) training on muscular strength and function of older adults. Methods Databases including PubMed, Web of Science, EBSCO host, Cochrane Library, CNKI, Wan Fang Data were searched to collect randomized controlled trials (RTCs) investigating the effects of BFR-LI training on muscular strength and function of older adults. The Cochrane bias risk assessment tool was applied to evaluate the methodological quality of the included studies, and acquired data were statistically analyzed using Stata 14.0 software. The retrieval period is from the establishment of the database to February 2022. Results Eighteen RCTs were included, with a total sample size of 419 people. Meta-analysis shows that BFR-LI training significantly improves the lower limb muscle strength (SMD: 0.66, 95%CI: [0.41,0.91], p < 0.001), and muscle function in Timed Up and Go Test (SMD: 0.79, 95%CI: [0.07,1.51], p < 0.05), and 30 Second Sit to Stand Test (SMD: 0.77, 95%CI: [0.13–1.40], p < 0.05). Different condition of control group (β = 0.48, 95% CI: [−0.98,-0.50], p < 0.01) and exercise duration (β = 1.05, 95% CI:[0.00,0.09], p < 0.05) were significant moderators in subgroup and meta-regression analyses. The effects of BFR-LI on strength gain are greater than regular LI-training in combined with resistance training and walking training, but weaker than the effect of high-intensity (HI) training. Conclusion BFR-LI training can effectively improve the muscular strength and function of the lower limbs of older adults. However, due to the limitations in the quality of the included research (inappropriate research design, small sample size, etc.), issues such as pressure intensity and exercise risk still need to be confirmed by more standardized and high-quality studies.
Article
Full-text available
Blood flow restriction (BFR) training (also known as Kaatsu training) is an increasingly common practice employed during resistance exercise by athletes attempting to enhance skeletal muscle mass and strength. During BFR training, blood flow to the exercising muscle is mechanically restricted by placing flexible pressurizing cuffs around the active limb proximal to the working muscle. This maneuver results in the accumulation of metabolites (e.g., protons, lactic acid) in the muscle interstitium that increase muscle force and promote muscle growth. Therefore, the premise of BFR training is to simulate and receive the benefits of high-intensity resistance exercise while merely performing low-intensity resistance exercise. This technique has also been purported to provide health benefits to the elderly, individuals recovering from joint injuries and cardiac rehabilitation patients. Since the seminal work of Alam and Smirk in the 1930s, it has been well established that reductions in blood flow to exercising muscle engage the exercise pressor reflex (EPR), a reflex that significantly contributes to the autonomic cardiovascular response to exercise. However, the EPR and its likely contribution to the BFR-mediated cardiovascular response to exercise is glaringly missing from the scientific literature. Inasmuch as the EPR has been shown to generate exaggerated increases in sympathetic nerve activity in disease states such as hypertension (HTN), heart failure (HF) and peripheral artery disease (PAD), concerns are raised that BFR training can be used safely for the rehabilitation of patients with cardiovascular disease as has been suggested. Copyright © 2015, American Journal of Physiology - Heart and Circulatory Physiology.
Thesis
Full-text available
[Motivation] Quadriceps or knee extensor weakness is considered not only as an important risk factor for osteoarthritis but also as the main determinant of physical function with knee osteoarthritis (KOA). Low-load resistance training with blood flow restriction training (BFRT) has previously shown to improve knee extensor strength whilst reducing risk of incident symptomatic KOA. BFRT could offer comparable increases in muscle size and strength as observed with traditional, high-load resistance training (HL-RT). BFRT may be a clinically relevant musculoskeletal rehabilitation modality as it does not require the high joint forces associated with HL-RT. [Research Focus] The focus of this dissertation was to elucidate the role of BFRT as a nonpharmacologic intervention for improving muscle strength and functionality in adults diagnosed with KOA. [Research Methods] These research aims were met through an extensive review of relevant literature pertaining to blood flow restriction training in KOA sufferers. [Findings] The findings from this dissertation provided promising evidence that BFRT to be safe and potentially effective in improving quadriceps strength in patients with knee-related weakness and atrophy. [Conclusion] The main conclusion drawn from this literature review is that BFRT could provide an equally effective and more tolerable approach to HL-RT whilst increasing knee extensor strength in symptomatic KOA patients. [Recommendation] This dissertation recommends that future research should determine whether changes in BFRT training dose or duration may improve quadriceps muscle cross-sectional area in KOA patients.
Article
Full-text available
Background: Increased physical activity has been recommended as an important lifestyle modification for the prevention and control of hypertension. Walking is a low-cost form of physical activity and one which most people can do. Studies testing the effect of walking on blood pressure have revealed inconsistent findings. Objectives: To determine the effect of walking as a physical activity intervention on blood pressure and heart rate. Search methods: We searched the following databases up to March 2020: the Cochrane Hypertension Specialised Register, CENTRAL (2020, Issue 2), Ovid MEDLINE, Ovid Embase, CINAHL, PsycINFO, SPORTDiscus, PEDro, the WHO International Clinical Trials Registry Platform, and ClinicalTrials.gov. We also searched the following Chinese databases up to May 2020: Index to Taiwan Periodical Literature System; National Digital Library of Theses and Dissertation in Taiwan; China National Knowledge Infrastructure (CNKI) Journals, Theses & Dissertations; and Wanfang Medical Online. We contacted authors of relevant papers regarding further published and unpublished work. The searches had no language restrictions. Selection criteria: Randomised controlled trials of participants, aged 16 years and over, which evaluated the effects of a walking intervention compared to non-intervention control on blood pressure and heart rate were included. Data collection and analysis: We used standard methodological procedures expected by Cochrane. Where data were not available in the published reports, we contacted authors. Pooled results for blood pressure and heart rate were presented as mean differences (MDs) between groups with 95% confidence intervals (CIs). We undertook subgroup analyses for age and sex. We undertook sensitivity analyses to assess the effect of sample size on our findings. Main results: A total of 73 trials met our inclusion criteria. These 73 trials included 5763 participants and were undertaken in 22 countries. Participants were aged from 16 to 84 years and there were approximately 1.5 times as many females as males. The characteristics of walking interventions in the included studies were as follows: the majority of walking interventions was at home/community (n = 50) but supervised (n = 36 out of 47 reported the information of supervision); the average intervention length was 15 weeks, average walking time per week was 153 minutes and the majority of walking intensity was moderate. Many studies were at risk of selection bias and performance bias. Primary outcome We found moderate-certainty evidence suggesting that walking reduces systolic blood pressure (SBP) (MD -4.11 mmHg, 95% CI -5.22 to -3.01; 73 studies, n = 5060). We found moderate-certainty evidence suggesting that walking reduces SBP in participants aged 40 years and under (MD -4.41 mmHg, 95% CI -6.17 to -2.65; 14 studies, n = 491), and low-certainty evidence that walking reduces SBP in participants aged 41 to 60 years (MD -3.79 mmHg, 95% CI -5.64 to -1.94, P < 0.001; 35 studies, n = 1959), and those aged 60 years of over (MD -4.30 mmHg, 95% CI -6.17 to -2.44, 24 studies, n = 2610). We also found low certainty-evidence suggesting that walking reduces SBP in both females (MD -5.65 mmHg, 95% CI -7.89 to -3.41; 22 studies, n = 1149) and males (MD -4.64 mmHg, 95% CI -8.69 to -0.59; 6 studies, n = 203). Secondary outcomes We found low-certainty evidence suggesting that walking reduces diastolic blood pressure (DBP) (MD -1.79 mmHg, 95% CI -2.51 to -1.07; 69 studies, n = 4711) and heart rate (MD -2.76 beats per minute (bpm), 95% CI -4.57 to -0.95; 26 studies, n = 1747). We found moderate-certainty evidence suggesting that walking reduces DBP for participants aged 40 years and under (MD -3.01 mmHg, 95% CI -4.44 to -1.58; 14 studies, n = 491) and low-certainty evidence suggesting that walking reduces DBP for participants aged 41 to 60 years (MD -1.74 mmHg, 95% CI -2.95 to -0.52; 32 studies, n = 1730) and those aged 60 years and over (MD -1.33 mmHg, 95% CI -2.40 to -0.26; 23 studies, n = 2490). We found moderate-certainty evidence that suggests walking reduces DBP for males (MD -2.54 mmHg, 95% CI -4.84 to -0.24; 6 studies, n = 203) and low-certainty evidence that walking reduces DBP for females (MD -2.69 mmHg, 95% CI -4.16 to -1.23; 20 studies, n = 1000). Only 21 included studies reported adverse events. Of these 21 studies, 16 reported no adverse events, the remaining five studies reported eight adverse events, with knee injury being reported five times. Authors' conclusions: Moderate-certainty evidence suggests that walking probably reduces SBP. Moderate- or low-certainty evidence suggests that walking may reduce SBP for all ages and both sexes. Low-certainty evidence suggests that walking may reduce DBP and heart rate. Moderate- and low-certainty evidence suggests walking may reduce DBP and heart rate for all ages and both sexes.
Article
This study investigated the autonomic and haemodynamic responses to different aerobic exercise loads, with and without blood flow restriction (BFR). In a crossover study, 21 older adults (8 males and 13 females) completed different aerobic exercise sessions: low load without BFR (LL) (40% VO2max), low load with BFR (LL-BFR) (40% VO2max + 50% BFR) and high load without BFR (HL) (70% VO2max). Heart rate variability and haemodynamic responses were recorded during rest and throughout 30 min of recovery. HL reduced R–R interval, the root mean square of successive difference of R–R intervals and high frequency during 30 min of recovery at a greater magnitude compared with LL and LL-BFR. Sympathetic–vagal balance increased the values for HL during 30 min of recovery at a greater magnitude when compared with LL and LL-BFR. Post-exercise haemodynamic showed reduced values of double product at 30 min of recovery compared to rest in LL-BFR, while HL showed higher values compared to rest, LL-BFR and LL. Reduced systolic blood pressure was observed for LL-BFR (30 min) compared to rest. Autonomic and haemodynamic responses indicate lower cardiovascular stress after LL-BFR compared to HL, being this method, besides the functional adaptations, a potential choice to attenuate the cardiovascular stress after exercise in older adults.
Article
Background and objective Low-load exercise training with blood flow restriction (BFR) can increase muscle strength and may offer an effective clinical musculoskeletal (MSK) rehabilitation tool. The aim of this review was to systematically analyse the evidence regarding the effectiveness of this novel training modality in clinical MSK rehabilitation. Design This is a systematic review and meta-analysis of peer-reviewed literature examining BFR training in clinical MSK rehabilitation (Research Registry; researchregistry91). Data sources A literature search was conducted across SPORTDiscus (EBSCO), PubMed and Science Direct databases, including the reference lists of relevant papers. Two independent reviewers extracted study characteristics and MSK and functional outcome measures. Study quality and reporting was assessed using the Tool for the assEssment of Study qualiTy and reporting in EXercise. Eligibility Search results were limited to exercise training studies investigating BFR training in clinical MSK rehabilitation, published in a scientific peer-reviewed journal in English. Results Twenty studies were eligible, including ACL reconstruction (n=3), knee osteoarthritis (n=3), older adults at risk of sarcopenia (n=13) and patients with sporadic inclusion body myositis (n=1). Analysis of pooled data indicated low-load BFR training had a moderate effect on increasing strength (Hedges’ g=0.523, 95% CI 0.263 to 0.784, p<0.001), but was less effective than heavy-load training (Hedges’ g=0.674, 95% CI 0.296 to 1.052, p<0.001). Conclusion Compared with low-load training, low-load BFR training is more effective, tolerable and therefore a potential clinical rehabilitation tool. There is a need for the development of an individualised approach to training prescription to minimise patient risk and increase effectiveness.
Article
During spaceflight missions, astronauts work in an extreme environment with several hazards to physical health and performance. Exposure to microgravity results in remarkable deconditioning of several physiological systems, leading to impaired physical condition and human performance, posing a major risk to overall mission success and crew safety. Physical exercise is the cornerstone of strategies to mitigate physical deconditioning during spaceflight. Decades of research have enabled development of more optimal exercise strategies and equipment onboard the International Space Station. However, the effects of microgravity cannot be completely ameliorated with current exercise countermeasures. Moreover, future spaceflight missions deeper into space require a new generation of spacecraft, which will place yet more constraints on the use of exercise by limiting the amount, size and weight of exercise equipment and the time available for exercise. Space agencies are exploring ways to optimise exercise countermeasures for spaceflight, specifically exercise strategies that are more efficient, require less equipment and are less time-consuming. Blood flow restriction exercise is a low intensity exercise strategy that requires minimal equipment and can elicit positive training benefits across multiple physiological systems. This method of exercise training has potential as a strategy to optimise exercise countermeasures during spaceflight and reconditioning in terrestrial and partial gravity environments. The possible applications of blood flow restriction exercise during spaceflight are discussed herein.
Article
Full-text available
Background: Blood flow restriction (BFR) training has been reported to have significant benefits on local skeletal muscle including increasing local muscle mass, strength, and endurance while exercising with lower resistance. As a result, patients unable to perform traditional resistance training may benefit from this technique. However, it is unclear what effects BFR may have on other body systems, such as the cardiovascular and pulmonary systems. It is important to explore the systemic effects of BFR training to ensure it is safe for use in physical therapy. Purpose: The purpose of this study was to systematically review the systemic effects of blood flow restriction training when combined with exercise intervention. Study design: Systematic review. Methods: Three literature searches were performed: June 2019, September 2019, and January 2020; using MedLine, ScienceDirect, PubMed, Cochrane Reviews and CINAHL Complete. Inclusion criteria included: at least one outcome measure addressing a cardiovascular, endocrinological, systemic or proximal musculoskeletal, or psychosocial outcome, use of clinically available blood flow restriction equipment, use of either resistance or aerobic training in combination with BFR, and use of quantitative measures. Exclusion criteria for articles included only measuring local or distal musculoskeletal changes due to BFR training, examining only passive BFR or ischemic preconditioning, articles not originating from a scholarly peer-reviewed journal, CEBM level of evidence less than two, or PEDro score less than four. Articles included in this review were analyzed with the CEBM levels of evidence hierarchy and PEDro scale. Results: Thirty-five articles were included in the review. PEDro scores ranged between 4 and 8, and had CEBM levels of evidence of 1 and 2. Common systems studied included cardiovascular, musculoskeletal, endocrine, and psychosocial. This review found positive or neutral effects of blood flow restriction training on cardiovascular, endocrinological, musculoskeletal, and psychosocial outcomes. Conclusions: Although BFR prescription parameters and exercise interventions varied, the majority of included articles reported BFR training to produce favorable or non-detrimental effects to the cardiovascular, endocrine, and musculoskeletal systems. This review also found mixed effects on psychosocial outcomes when using BFR. Additionally, this review found no detrimental outcomes directly attributed to blood flow restriction training on the test subjects or outcomes tested. Thus, BFR training may be an effective intervention for patient populations that are unable to perform traditional exercise training with positive effects other than traditional distal muscle hypertrophy and strength and without significant drawbacks to the individual. Level of evidence: 1b.
Article
Full-text available
Purpose Blood flow restriction (BFR) with low-intensity resistance training has been shown to result in hypertrophy of skeletal muscle. In this study, we tested the hypothesis that BFR during the rest periods between acute, high-intensity resistance exercise sessions (70% of 1 repetition maximum, 7 sets with 10 repetitions) enhances the effects of the resistance training. Methods A total of 7 healthy young men performed squats, and between sets BFR was carried out on 1 leg while the other leg served as a control. Because BFR was applied during rest periods, even severe occlusion pressure (approximately 230 mm Hg), which almost completely blocked blood flow, was well-tolerated by the participants. Five muscle-specific microRNAs were measured from the biopsy samples, which were taken 2 h after the acute training. Results Doppler data showed that the pattern of blood flow recovery changed significantly between the first and last BFR. MicroRNA-206 levels significantly decreased in the BFR leg compared to the control. The mRNA levels of RAC-β serine/threonine-protein kinase v22, nuclear respiratory factor 1, vascular endothelial growth factor, lupus Ku autoantigen protein p70 genes (p < 0.05), and paired box 7 (p < 0.01) increased in the BFR leg. The protein levels of paired box 7, nuclear respiratory factor 1, and peroxisome proliferator-activated receptor γ coactivator 1α did not differ between the BFR leg and the control leg. Conclusion Data revealed that BFR, during the rest periods of high-load resistance training, could lead to mRNA elevation of those proteins that regulate angiogenesis, mitochondrial biogenesis, and muscle hypertrophy and repair. However, BFR also can cause DNA damage, judging from the increase in mRNA levels of lupus Ku autoantigen protein p70.
Article
Full-text available
Aging is associated with progressive losses of muscle mass (sarcopenia) and strength (dynapenia) leading to reduced functional capacity. Traditional aerobic and resistance exercises are commonly recommended to enhance health and mitigate aging related performance concerns. Recently, blood flow restriction (BFR) exercise has gained scientific merit as a hybrid aerobic and resistance exercise intervention that may be suitable for application in older adults and following musculoskeletal injury to both mitigate and treat the resulting sarcopenia or dynapenia. Muscle hypertrophy ranging from <1% to 2.6% per week and muscle strength gain ranging from <1% to 5.9% per week have been reported following BFR exercise training when combined with various methods (walking, body weight, elastic bands, and traditional weight training). Further, given the projected increase in orthopedic surgeries in the aging population, the anabolic potential of BFR exercise methodology has gained additional interest the area of clinical rehabilitation following musculoskeletal insult. In particular, older adults recovering from various medical procedures may benefit from BFR exercise in order to regain muscular strength and size during recovery to avoid any additional complications from anabolic resistance, weakness, or disuse. Although care should be taken when selecting BFR exercises over traditional therapy interventions, there is evidence BFR exercise is a suitable intervention to mitigate sarcopenia and dynapenia and enhance muscle strength and mass recovery following various clinical conditions. Further, as BFR exercise provides an additional intervention to improve functional capacity by increasing muscle strength, mass and endurance, it’s utility in mitigating sarcopenia and dynapenia in at risk individuals (ie, frail elderly, postoperative) is becoming more apparent.
Article
INTRODUCTION: During spaceflight missions, astronauts work in an extreme environment with several hazards to physical health and performance. Exposure to microgravity results in remarkable deconditioning of several physiological systems, leading to impaired physical condition and human performance, posing a major risk to overall mission success and crew safety. Physical exercise is the cornerstone of strategies to mitigate physical deconditioning during spaceflight. Decades of research have enabled development of more optimal exercise strategies and equipment onboard the International Space Station. However, the effects of microgravity cannot be completely ameliorated with current exercise countermeasures. Moreover, future spaceflight missions deeper into space require a new generation of spacecraft, which will place yet more constraints on the use of exercise by limiting the amount, size, and weight of exercise equipment and the time available for exercise. Space agencies are exploring ways to optimize exercise countermeasures for spaceflight, specifically exercise strategies that are more efficient, require less equipment, and are less time-consuming. Blood flow restriction exercise is a low intensity exercise strategy that requires minimal equipment and can elicit positive training benefits across multiple physiological systems. This method of exercise training has potential as a strategy to optimize exercise countermeasures during spaceflight and reconditioning in terrestrial and partial gravity environments. The possible applications of blood flow restriction exercise during spaceflight are discussed herein.Hughes L, Hackney KJ, Patterson SD. Optimization of exercise countermeasures to spaceflight using blood flow restriction. Aerosp Med Hum Perform. 2021; 93(1):32-45.
Article
Background: The resistance training with blood flow restriction (BFR) presents results in strength gain and muscle hypertrophy. However, there are no data that evaluate the long-term adaptation of the autonomic nervous system and its influence on the performance, especially with eccentric contractions. Objective: To perform a systematic autonomous monitoring during eccentric training with BFR at different loads and to correlate them with possible changes in the performance METHODS: This is a 4-arms, randomized controlled and single blind trial. Sixty men were randomized in four groups: low and high load eccentric exercise (LL and HL); LL and HL with BFR (LL-BFR and HL-BFR). The participants underwent 18 sessions of eccentric exercise for the dominant quadriceps femoris muscle in the isokinetic dynamometer. The performance (strength through isometric, concentric and eccentric peaks torque on the isokinetic dynamometer and Single-leg Hop Test) was evaluated one week before, in the fourth week and one week after the end of the training program. Heart rate variability (HRV) through vagal and global indices was evaluated daily for 15 minutes before each session. Results: there was a significant correlation between performance and HRV for LL and HL-BFR groups, with an increase in parasympathetic indices in the first group and an increase in performance in the second group. Conclusion: HRV indices are correlated with performance. However, in the LL group, there was an increase in parasympathetic indices without repercussions on performance while, in the HL-BFR group, there was an increase in performance and no repercussion in the autonomic indices. This article is protected by copyright. All rights reserved.
Article
Full-text available
The effects of autonomic disruption and inactivity were studied on the venous vascular system. Forty-eight subjects, 24 with spinal cord injury (SCI) and 12 sedentary and 12 active able-bodied controls, participated in this study. Peripheral autonomic data were obtained to estimate sympathetic vasomotor control [low-frequency component of systolic blood pressure (LF(SBP))]. Vascular parameters were determined using strain-gauge venous occlusion plethysmography: venous capacitance (VC), venous emptying rate (VER), and total venous outflow (VO(t)). An additional vascular parameter was calculated: venous compliance [(VC/occlusion pressure) x 100]. VC and VO(t) were significantly different (SCI < sedentary < active). VER adjusted for VC was not different for any group comparison, whereas venous compliance was significantly lower in the SCI group than in the able-bodied groups and in the sedentary group compared with the active group. Regression analysis for the total group revealed a significant relationship between LF(SBP) and venous compliance (r = 0.64, P < 0.0001). After controlling for LF(SBP) through analysis of covariance, we found that mean differences for all venous vascular parameters did not change from unadjusted mean values. Our findings suggest that in subjects with SCI, the loss of sympathetic vasomotor tone contributes more than inactivity to reductions in venous vascular function. Heightened VC, VO(t), vasomotor tone, and venous compliance in the active group compared with the sedentary group imply that regular endurance training contributes to optimal venous vascular function and peripheral autonomic integrity.
Article
Full-text available
The effects of resistance exercise combined with vascular occlusion on muscle function were investigated in highly trained athletes. Elite rugby players (n = 17) took part in an 8 week study of exercise training of the knee extensor muscles, in which low-intensity [about 50% of one repetition maximum] exercise combined with an occlusion pressure of about 200 mmHg (LIO, n = 6), low-intensity exercise without the occlusion (LI, n = 6), and no exercise training (untrained control, n = 5) were included. The exercise in the LI group was of the same intensity and amount as in the LIO group. The LIO group showed a significantly larger increase in isokinetic knee extension torque than that in the other two groups (P < 0.05) at all the velocities studied. On the other hand, no significant difference was seen between LI and the control group. In the LIO group, the cross-sectional area of knee extensors increased significantly (P < 0.01), suggesting that the increase in knee extension strength was mainly caused by muscle hypertrophy. The dynamic endurance of knee extensors estimated from the decreases in mechanical work production and peak force after 50 repeated concentric contractions was also improved after LIO, whereas no significant change was observed in the LI and control groups. The results indicated that low-intensity resistance exercise causes, in almost fully trained athletes, increases in muscle size, strength and endurance, when combined with vascular occlusion.
Article
Full-text available
We investigated the hemodynamic and hormonal responses to a short-term low-intensity resistance exercise (STLIRE) with the reduction of muscle blood flow. Eleven untrained men performed bilateral leg extension exercise under the reduction of muscle blood flow of the proximal end of both legs pressure-applied by a specially designed belt (a banding pressure of 1.3 times higher than resting systolic blood pressure, 160-180 mmHg), named as Kaatsu. The intensity of STLIRE was 20% of one repetition maximum. The subjects performed 30 repetitions, and after a 20-seconds rest, they performed three sets again until exhaustion. The superficial femoral arterial blood flow and hemodynamic parameters were measured by using the ultrasound and impedance cardiography. Serum concentrations of growth hormone (GH), vascular endothelial growth factor (VEGF), noradrenaline (NE), insulin-like growth factor (IGF)-1, ghrelin, and lactate were also measured. Under the conditions with Kaatsu, the arterial flow was reduced to about 30% of the control. STLIRE with Kaatsu significantly increased GH (0.11+/-0.03 to 8.6+/-1.1 ng/ml, P < 0.01), IGF-1 (210+/-40 to 236+/-56 ng/ml, P < 0.01), and VEGF (41+/-13 to 103+/-38 pg/ml, P < 0.05). The increase in GH was related to neither NE nor lactate, but the increase in VEGF was related to that in lactate (r = 0.57, P < 0.05). Ghrelin did not change during the exercise. The maximal heart rate (HR) and blood pressure (BP) in STLIRE with Kaatsu were higher than that without Kaatsu. Stroke volume (SV) was lower due to the decrease of the venous return by Kaatsu, but, total peripheral resistance (TPR) did not change significantly. These results suggest that STLIRE with Kaatsu significantly stimulates the exercise-induced GH, IGF, and VEGF responses with the reduction of cardiac preload during exercise, which may become a unique method for rehabilitation in patients with cardiovascular diseases.
Article
The purpose of the present study was to examine the blood pressure and heart rate response to walking with and without blood flow restriction (KAATSU-walk) in the elderly. Seven active subjects (2 men, 5 women) aged between 64 to 78 years (mean age, 68.9 ± 6.3 years) performed walking test without (Control) and with KAATSU (cuff pressure 160 mmHg and 200 mmHg) on separate days. The exercise consisted of level walking at 67 m/min (4 km/hr) for 20 min. Systolic (SBP) and diastolic (DBP) blood pressure was recorded using an automatic blood pressure monitor, and mean arterial pressure (MAP) was calculated [MAP = DBP + (SBP - DBP)/3]. Heart rate (HR) and ratings of perceived exertion (RPE) were also recorded during the test. There were no significant differences (P>0.05) in blood pressure responses between the Control and KAATSU-160mmHg exercise, however significantly higher blood pressures were observed for the KAATSU-200mmHg exercise (112-127mmHg for MAP) compared to the Control. However, these values are still lower than those of previous reported during moderate to heavy resistance exercise. The correlations between HR and MAP during each exercise condition were all statistically significant (range from r=0.83 to r=0.94; p<0.05). However, the intercept of the curve was highest in KAATSU-200mmHg exercise (i.e. MAP response to the same HR was higher), suggesting the increased total peripheral resistance with high occlusive pressure. In conclusion, our results indicate that during slow walk exercise with KAATSU, level of occlusive pressure can significantly impact upon the HR and MAP responses in the elderly, These findings are consistent with the idea that the occlusive pressure by itself can significantly modulate the cardiovascular response during low-intensity KAATSU-walk.
Article
The KAATSU training is a unique method of muscle training with restricting venous blood flow, which might be applied to prevent muscle atrophy during space flight, but the effects of KAATSU in microgravity remain unknown. We investigated the hemodynamic responses to KAATSU during actually simulated weightlessness (6 degrees head-down tilt for 24 h, n = 8), and compared those to KAATSU in the seated position before bed rest. KAATSU was applied to the proximal ends of both the thighs. In the seated position before bed rest, sequential incrementing of KAATSU cuff pressure and altering the level of blood flow restriction resulted in a decrease in stroke volume (SV) with an increase in heart rate (HR). KAATSU (150-200 mmHg) decreased SV comparable to standing. Following 24-h bed rest, body mass, blood volume (BV), plasma volume (PV), and diameter of the inferior vena cava (IVC) were significantly reduced. Norepinephrine (NOR), vasopressin (ADH), and plasma renin activity (PRA) tend to be reduced. A decrease in SV and CO induced by KAATSU during the simulated weightlessness was larger than that in the seated position before bed rest, and one of eight subjects developed presyncope due to hypotension during 100 mmHg KAATSU. High-frequency power (HF(RR)) decreased during KAATSU and standing, while low-frequency/high-frequency power (LF(RR)/HF(RR)) increased significantly. NOR, ADH and PRA also increased during KAATSU. These results indicate that KAATSU blood flow restriction reproduces the effects of standing on HR, SV, NOR, ADH, PRA, etc., thus stimulating a gravity-like stress during simulated weightlessness. However, syncope due to lower extremity blood pooling and subsequent reduction of venous return may be induced during KAATSU in microgravity as reported in cases of lower-body negative pressure.
Article
Increased leg venous compliance may contribute to postflight orthostatic intolerance in astronauts. We reported that leg compliance was inversely related to the size of the muscle compartment. The purpose of this study was to test the hypothesis that reduced muscle compartment after long-duration exposure to microgravity would cause increased leg compliance. Eight men, 31-45 yr old, were measured for vascular compliance of the calf and serial circumferences of the calf before and after 30 days of continuous 6 degrees head-down bed rest. Cross-sectional areas (CSA) of muscle, fat, and bone compartments in the calf were determined before and after bed rest by computed tomography. From before to after bed rest, calculated calf volume (cm3) decreased (P less than 0.05) from 1,682 +/- 83 to 1,516 +/- 76. Calf muscle compartment CSA (cm2) also decreased (P less than 0.05) from 74.2 +/- 3.6 to 70.6 +/- 3.4; calf compliance (ml.100 ml-1.mmHg-1.100) increased (P less than 0.05) from 3.9 +/- .7 to 4.9 +/- .5. The percent change in calf compliance after bed rest was significantly correlated with changes in calf muscle compartment CSA (r = 0.72, P less than 0.05). The increased leg compliance observed after exposure to simulated microgravity can be partially explained by reduced muscle compartment. Countermeasures designed to minimize muscle atrophy in the lower extremities may be effective in ameliorating increased venous compliance and orthostatic intolerance after spaceflight.
Article
Leg compliance is "causally related with greater susceptibility" to orthostatic stress. Since peak O2 uptake (peak VO2) and muscle strength may be related to leg compliance, we examined the relationships between leg compliance and factors related to muscle size and physical fitness. Ten healthy men, 25-52 yr, underwent tests for determination of vascular compliance of the calf (Whitney mercury strain gauge), peak VO2 (Bruce treadmill), calf muscle strength (Cybex isokinetic dynamometer), body composition (densitometry), and anthropometric measurements of the calf. Cross-sectional areas (CSA) of muscle, fat, and bone in the calf were determined by computed tomography scans. Leg compliance was not significantly correlated with any variables associated with physical fitness per se (peak VO2, calf strength, age, body weight, or composition). Leg compliance correlated with calf CSA (r = -0.72, P less than 0.02) and calculated calf volume (r = -0.67, P less than 0.03). The most dominant contributing factor to the determination of leg compliance was CSA of calf muscle (r = -0.60, P less than 0.06), whereas fat and bone were poor predictors (r = -0.11 and 0.07, respectively). We suggest that leg compliance is less when there is a large muscle mass providing structural support to limit expansion of the veins. This relationship is independent of aerobic and/or strength fitness level of the individual.
Article
The volume-pressure relationship of the vasculature of the body as a whole, its vascular capacitance, requires a measurement of the mean circulatory filling pressure (Pmcf). A change in vascular capacitance induced by reflexes, hormones, or drugs has physiological consequences similar to a rapid change in blood volume and thus strongly influences cardiac output. The Pmcf is defined as the mean vascular pressure that exists after a stop in cardiac output and redistribution of blood, so that all pressures are the same throughout the system. The Pmcf is thus related to the fullness of the circulatory system. A change in Pmcf provides a uniquely useful index of a change in overall venous smooth muscle tone if the blood volume is not concomitantly changed. The Pmcf also provides an estimate of the distending pressure in the small veins and venules, which contain most of the blood in the body and comprise most of the vascular compliance. Thus the Pmcf, which is normally independent of the magnitude of the cardiac output, provides an estimate of the upstream pressure that determines the rate of flow returning to the heart.
Article
Leg volume changes were assessed in healthy volunteers by mercury strain gauge postural plethysmography in order to study the effects of different types of physical training on lower limb venous distensibility and emptying. Seven endurance trained subjects (E), seven muscle strength trained subjects (M) and seven sedentary subjects (S) were submitted to a tilt table test. The test measured leg filling volumes FV (ml.100 ml-1) during 30 head-up tilt, half-emptying time T1/2 (seconds) and venous output at the 6th second of emptying (VO6) (ml.100 ml-1.min-1) during return to horizontal position. Comparative tests were made using an ANOVA test. Results showed significantly higher values for FV and VO6 in E (FV: 3.9 +/- 0.2 ml.100 ml-1 in E vs 2.5 +/- 0.2 and 2.2 +/- 0.2 ml.100 ml-1 in M and S, respectively; VO6: 9.2 +/- 1.1 ml.100 ml-1.min-1 in E vs 6.9 +/- 0.7 and 5.5 +/- 0.5 ml.100 ml-1.min-1 in M and S, respectively) whereas no significant differences were observed between groups for T1/2. M and S had the same physiological responses to orthostatic stress. Endurance training seems to increase lower limb venous distensibility without affecting venous emptying and venous return from the lower limbs. These results suggest that the greater venous distensibility in endurance-trained subjects does not result from alterations of the visco-elastic properties of deep vein walls and that it is probably a physical response to hypervolemia consecutive to chronic aerobic training.
Article
Venous compliance in the calf of humans and its importance for capacitance function in relation to age were studied with the aid of 22, 44, and 59 mmHg lower body negative pressure (LBNP). Negative pressure transmission to the calf as well as changes in calf volume were studied, and venous compliance was calculated [change in volume with pressure change (dV/dP)]. The change in capacitance response of the calf with age (20-70 yr) was evaluated during LBNP 44 mmHg. Transmission of negative pressure to the subcutaneous tissue was almost full without any changes with age (92%). However, it was reduced to 80% in the underlying muscle tissue, irrespective of depth. Venous compliance in the young was 0.051 ml . 100 ml-1 . mmHg-1 and was reduced by 45% to 0.029 ml . 100 ml-1 . mmHg-1 in the old (P < 0.05). Accordingly, the capacitance response was reduced by 0.015 ml . 100 ml-1 . yr-1 (P < 0.005). Furthermore, the hemodynamic response to hypovolemic circulatory stress was attenuated with age. The reduced pressure transmission in muscle tissue is probably due to restriction of the muscle fascia envelope. The reduced venous compliance with age and the concomitant reduction in capacitance response during LBNP have implications for both the sympathetic reflex responses as well as the capacitance response during acute hypovolemic circulatory stress, which might be defected in aging humans.
Article
Venous compliance in the legs of aging man has been found to be reduced with decreased blood pooling (capacitance response) in dependent regions, and this might lead to misinterpretations of age-related changes in baroreceptor function during orthostasis. The hemodynamic response to hypovolemic circulatory stress was studied with the aid of lower-body negative pressure (LBNP) of 60 cmH(2)O in 33 healthy men [18 young (mean age 22 yr) and 15 old (mean age 65 yr)]. Volumetric technique was used in the study of capacitance responses in the calf and arm as well as transcapillary fluid absorption in the arm. LBNP led to smaller increase in heart rate (P < 0.001) and peripheral resistance (P < 0.01) and reduced transcapillary fluid absorption in the arm (P < 0.05) in old subjects. However, blood pooling in the calf was reduced in old subjects (1.66 +/- 0.10 vs. 2.17 +/- 0.13 ml/100 ml tissue; P < 0. 01). Accordingly, during similar blood pooling in the calf (LBNP 80 cmH(2)O in old subjects), no changes in cardiovascular reflex responses with age were found. The capacitance response in the arm (mobilization of peripheral blood to the central circulation) was still reduced, however (0.67 +/- 0.10 vs. 1.37 +/- 0.11 ml/100 ml tissue; P < 0.01). Thus the reduced cardiovascular reflex response found in the elderly during orthostatic stress seems to be caused by a reduced capacitance response in the legs with age and a concomitant smaller central hypovolemic stimulus rather than a reduced efficiency of the reflex response. With similar hypovolemic circulatory stress, no changes in cardiovascular reflex responses are seen with age. The capacitance response in the arm (mobilization of peripheral blood toward the central circulation) is reduced, however, by approximately 50% in the elderly. This might seriously impede the possibility of survival of an acute blood loss.
Article
We determined the independent and interactive influences of aging and habitual endurance exercise on calf venous compliance in humans. We tested the hypotheses that calf venous compliance is 1) reduced with age in sedentary and endurance-trained men, and 2) elevated in young and older endurance-trained compared with age-matched sedentary men. We studied 8 young (28 +/- 1 yr) and 8 older (65 +/- 1) sedentary, and 8 young (27 +/- 1) and 8 older (63 +/- 2) endurance-trained men. Calf venous compliance was measured in supine subjects by inflating a venous collecting cuff, placed above the knee, to 60 mmHg for 8 min and then decreasing cuff pressure at 1 mmHg/s to 0 mmHg. Calf venous compliance was determined using the first derivative of the pressure-volume relation during cuff pressure reduction (compliance = beta(1) + 2. beta(2). cuff pressure). Calf venous compliance was reduced with age in sedentary (approximately 40%) and endurance-trained men (approximately 20%) (both P < 0.01). Furthermore, calf venous compliance was approximately 70-120% greater in endurance-trained compared with age-matched sedentary men and approximately 30% greater in older endurance-trained compared with young sedentary men (both P < 0.01). These data indicate that calf venous compliance is reduced with age in sedentary and endurance-trained men, but compliance is better preserved in endurance-trained men.
Article
It is warranted to test the hypothesis that the orthostatic tolerance does not diminish in the aging process per se in healthy individuals. The purpose of the present study was to examine the effects of aging on cardiovascular response and baroreflex sensitivity during lower body negative pressure (LBNP) with a special reference to leg compliance. Fifteen healthy old male subjects [mean age 68.2 +/- (SE) 0.8 years] and 22 young male subjects [mean age 21.4 +/- (SE) 0.3 years] underwent a 21-min bout of ramped LBNP (from 0 to -60 mm Hg, 10 mm Hg each for 3 min). Heart rate (HR), blood pressure, stroke volume (SV), forearm blood flow, and leg volume were measured throughout the experimental period. The arterial baroreflex sensitivity was calculated from spontaneous changes in beat-to-beat arterial pressure and HR during LBNP. The leg compliance was lower, and the orthostatic tolerance index was higher in old than in young participants. The LBNP-associated increases in leg volume and HR and the decreases in SV were lower in old subjects, suggesting that the reduction of venous return was less in magnitude in old subjects during LBNP. The baseline value of baroreflex sensitivity evaluated by the sequence analysis was smaller, and no LBNP-related change was observed in old subjects, whereas a gradual LBNP-related reduction was observed in young subjects. The slope of regression between DeltaSV and change in forearm vascular resistance during LBNP was identical in both age groups. We conclude that: (1) aging per se does not increase the intolerance to orthostatic stress induced by LBNP; (2) a low magnitude of venous return reduction during LBNP contributes to a higher tolerance in the old because of lower leg compliance, and (3) the sensitivity of baroreflex control of the HR is attenuated in the old; however, there is no deterioration of the sensitivity of the peripheral vasoconstriction during LBNP.
Article
The purpose of this paper is to report our recent investigations on the relationship between sympathetic tone and leg venous compliance, as well as on the baroreflex control of leg venous compliance after simulated microgravity exposure in healthy humans.
Article
Wear and tear degenerative patterns of the arterial system of the lower extremities have been studied in an age series. The intensity of these alterations has been correlated with the distribution of the atheromatous plaques and thrombosis as well as with the effective tension at various levels as calculated by Burton's formula. Evidence is presented for the concept that the lipids in atheromatous plaques arise as a product of these degenerative reactions within the vessel wall, rather than by diffusion from the circulation through the endothelial barrier.
Article
Venous function may be altered by bed rest deconditioning. Yet the contribution of altered venous compliance to the orthostatic intolerance observed after bed rest is uncertain. The purpose of this study was to assess the effect of 18 days of bed rest on leg and arm (respectively large and small change in gravitational gradients and use patterns) venous properties. We hypothesized that the magnitude of these venous changes would be related to orthostatic intolerance. Eleven healthy subjects (10 men, 1 woman) participated in the study. Before (pre) and after (post) 18 days of 6 degrees head-down tilt bed rest, strain gauge venous occlusion plethysmography was used to assess limb venous vascular characteristics. Leg venous compliance was significantly decreased after bed rest (pre: 0.048 +/- 0.007 ml x 100 ml(-1) x mmHg(-1), post: 0.033 +/- 0.007 ml x 100 ml(-1) x mmHg(-1); P < 0.01), whereas arm compliance did not change. Leg venous flow resistance increased significantly after bed rest (pre: 1.73 +/- 1.08 mmHg x ml(-1) x 100 ml x min, post: 3.10 +/- 1.00 mmHg x ml(-1) x 100 ml x min; P < 0.05). Maximal lower body negative pressure tolerance, which was expressed as cumulative stress index (pressure x time), decreased in all subjects after bed rest (pre: 932 mmHg x min, post: 747 mmHg x min). The decrease in orthostatic tolerance was not related to changes in leg venous compliance. In conclusion, this study demonstrates that after bed rest, leg venous compliance is reduced and leg venous outflow resistance is enhanced. However, these changes are not related to measures of orthostatic tolerance; therefore, alterations in venous compliance do not to play a major role in orthostatic intolerance after 18 days of head-down tilt bed rest.
Article
Aging and chronic exercise training influence leg venous compliance. Venous compliance affects responses to an orthostatic stress. The extent to which exercise training in a previously sedentary older population will affect venous compliance and tolerance to the simulated orthostatic stress of maximal lower body negative pressure (LBNP) is unknown. The purpose of this investigation is to determine the influence of a 6-mo endurance-training program on calf venous compliance and responses and tolerance to maximal LBNP in older men and women. Twenty participants (exercise group: n = 10, 5 men, 5 women; control group: n = 10, 6 men, 4 women; all >60 yr) underwent graded LBNP to presyncope or 4 min at -100 mmHg before and after a 6-mo endurance-training program. Utilizing venous occlusion plethysmography, calf venous compliance was determined in both groups using the first derivative of the pressure-volume relation during cuff pressure reduction before training, at 3 mo, and at the end of the training program. The exercise group improved their fitness with the 6-mo endurance-training program, whereas the control group did not change (14 +/- 3 vs. <1 +/- 2%; P < 0.05). LBNP tolerance did not differ between groups or across trials (P = 0.47). Venous compliance was not different between groups or trials, either initially or after 3 mo of endurance training, but tended to be greater in the exercise group after 6 mo of training (P = 0.08). These data suggest that a 6-mo endurance-training program may improve venous compliance without affecting tolerance to maximal LBNP in older participants.
Article
Previous studies have shown that low-intensity resistance training with restricted muscular venous blood flow (Kaatsu) causes muscle hypertrophy and strength gain. To investigate the effects of daily physical activity combined with Kaatsu, we examined the acute and chronic effects of walk training with and without Kaatsu on MRI-measured muscle size and maximum dynamic (one repetition maximum) and isometric strength, along with blood hormonal parameters. Nine men performed Kaatsu-walk training, and nine men performed walk training alone (control-walk). Training was conducted two times a day, 6 days/wk, for 3 wk using five sets of 2-min bouts (treadmill speed at 50 m/min), with a 1-min rest between bouts. Mean oxygen uptake during Kaatsu-walk and control-walk exercise was 19.5 (SD 3.6) and 17.2 % (SD 3.1) of treadmill-determined maximum oxygen uptake, respectively. Serum growth hormone was elevated (P < 0.01) after acute Kaatsu-walk exercise but not in control-walk exercise. MRI-measured thigh muscle cross-sectional area and muscle volume increased by 4-7%, and one repetition maximum and maximum isometric strength increased by 8-10% in the Kaatsu-walk group. There was no change in muscle size and dynamic and isometric strength in the control-walk group. Indicators of muscle damage (creatine kinase and myoglobin) and resting anabolic hormones did not change in both groups. The results suggest that the combination of leg muscle blood flow restriction with slow-walk training induces muscle hypertrophy and strength gain, despite the minimal level of exercise intensity. Kaatsu-walk training may be a potentially useful method for promoting muscle hypertrophy, covering a wide range of the population, including the frail and elderly.
Article
The application of an orthostatic stress such as lower body negative pressure (LBNP) has been proposed to minimize the effects of weightlessness on the cardiovascular system and subsequently to reduce the cardiovascular deconditioning. The KAATSU training is a novel method to induce muscle strength and hypertrophy with blood pooling in capacitance vessels by restricting venous return. Here, we studied the hemodynamic, autonomic nervous and hormonal responses to the restriction of femoral blood flow by KAATSU in healthy male subjects, using the ultrasonography and impedance cardiography. The pressurization on both thighs induced pooling of blood into the legs with pressure-dependent reduction of femoral arterial blood flow. The application of 200 mmHg KAATSU significantly decreased left ventricular diastolic dimension (LVDd), cardiac output (CO) and diameter of inferior vena cava (IVC). Similarly, 200 mmHg KAATSU also decreased stroke volume (SV), which was almost equal to the value in standing. Heart rate (HR) and total peripheral resistance (TPR) increased in a similar manner to standing with slight change of mean blood pressure (mBP). High-frequency power (HF(RR)) decreased during both 200 mmHg KAATSU and standing, while low-frequency/high-frequency power (LF(RR)/HF(RR)) increased significantly. During KAATSU and standing, the concentration of noradrenaline (NA) and vasopressin (ADH) and plasma renin activity (PRA) increased. These results indicate that KAATSU in supine subjects reproduces the effects of standing on HR, SV, TPR, etc., thus stimulating an orthostatic stimulus. And, KAATSU training appears to be a useful method for potential countermeasure like LBNP against orthostatic intolerance after spaceflight.
The Authors Clinical Physiology and Functional Imaging Ó 2011 Scandinavian Society of Clinical Physiology and Nuclear Medicine 31
  • Bfr Walking
  • H Venous Compliance
  • Iida
BFR walking and venous compliance, H. Iida et al. Ó 2011 The Authors Clinical Physiology and Functional Imaging Ó 2011 Scandinavian Society of Clinical Physiology and Nuclear Medicine 31, 6, 472–476