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Exercise prescription in cardiac rehabilitation needs to be more accurate
... The inconsistency between intensity domains claims the need for adjustment and new indicators in intensity prescription, proposed by the 2020 position paper from the European Association of Preventive Cardiology (EPAC) [5]. Moreover, individualized prescriptions based on cardiopulmonary exercise tests and individual thresholds such as the first and second ventilatory threshold are recommended [5][6][7]. ...
... A more individualized prescription and increased consideration of exercise intensity prescription including %P max was recommended by EPAC [5]. Therefore, exercise prescription via fixed percentage of HR max should be avoided and individual thresholds or at least percentages of P max are recommended, especially in individuals on β-blocker treatment in order to avoid overloading [7]. ...
(1): Heart rate performance curve (HRPC) in incremental exercise was shown to be not uniform, causing false intensity estimation applying percentages of maximal heart rate (HRmax). HRPC variations are mediated by β-adrenergic receptor sensitivity. The aim was to study age and sex dependent differences in HRPC patterns in adults with β-blocker treatment (BB) and healthy controls (C). (2): A total of 535 (102 female) BB individuals were matched 1:1 for age and sex (male 59 ± 11 yrs, female 61 ± 11 yrs) in C. From the maximum incremental cycle ergometer exercise a first and second heart rate (HR) threshold (Th1 and Th2) was determined. Based on the degree of the deflection (kHR), HRPCs were categorized as regular (downward deflection (kHR > 0.1)) and non-regular (upward deflection (kHR < 0.1), linear time course). (3): Logistic regression analysis revealed a higher odds ratio to present a non-regular curve in BB compared to C (females showed three times higher odds). The odds for non-regular HRPC in BB versus C decreased with older age (OR interaction = 0.97, CI = 0.94–0.99). Maximal and submaximal performance and HR variables were significantly lower in BB (p < 0.05). %HRmax was significantly lower in BB versus C at Th2 (male: 77.2 ± 7.3% vs. 80.8 ± 5.0%; female: 79.2 ± 5.1% vs. 84.0 ± 4.3%). %Pmax at Th2 was similar in BB and C. (4): The HRPC pattern in incremental cycle ergometer exercise is different in individuals receiving β-blocker treatment compared to healthy individuals. The effects were also dependent on age and sex. Relative HR values at Th2 varied substantially depending on treatment. Thus, the percentage of Pmax seems to be a stable and independent indicator for exercise intensity prescription.
... If CVR participants do not achieve or sustain HRTZ, the exercise stimulus may be suboptimal, and consequently, improvements in functional capacity may be hindered 10,11 . Therefore, this study aimed to assess the actual training intensity relative to the prescribed HRTZ, changes in functional capacity following exercise training, and the relationship between training intensity and functional capacity. ...
Objectives: To investigate the effect of exercise intensity on functional capacity in individuals with coronary artery disease, assess adherence to the heart rate training zone (HRTZ), and determine the relationship between trained intensity and functional capacity. Methods: A retrospective study was conducted on the medical records of 54 outpatients with coronary artery disease in a public hospital. The prescribed intensity started at 50%–60% of the heart rate reserve, increasing monthly to 70%–80% by the third month. Spearman’s test was used to assess the correlation between improvement in distance in the incremental shuttle walk test (ISWT), exercise intensity, and rating of perceived exertion (Borg–RPE). Adherence was classified as ‘below’ when HRTZ was not achieved in any phase of the program, ‘intermediate’ when HR was within the HRTZ for one or two months, and ‘above’ when HR was at or higher than HRTZ ≥ two months. Improvement was tested using t-test and one-way ANOVA. Results: 51.9% of participants had an increase in ISWT of ≥70 m (p < 0.0001). In at least one month, 50.9% trained below HRTZ. The trained intensity did not fall below 8.6% of the prescribed HRTZ minimum threshold. Changes in ISWT were not significantly correlated with exercise intensity (p = 0.87) or Borg–RPE (p = 0.16). Conclusion: While a significant increase in functional capacity was found, considerable heterogeneity in changes were observed. This may, in part, be related to adherence to HRTZ with progressive exercise intensity and to the variability in exercise volume in cardiovascular rehabilitation programs.
... Although energy supplies (aerobic and anaerobic energy) and activations of muscle fibres (type I, IIA, and IIB) during almost all exercise activities are not exclusive, there are dominant energy supplies and muscle fibre recruitments with their own attributes in different training zones divided by the first and second ventilation threshold, eliciting in corresponding physiological responses, respectively ( Figure 1A). 2 One of which is often overlooked that post-exercise metabolic responses to HIIT will remain elevated in an attempt to compensate for oxygen deficit driven by 'high intensity' during exercise. 3 Consequently, HIIT may be underestimated despite matching total energy expenditure between HIIT and MICT with isocaloric protocols, which will potentially contribute to maximizing effect size of HIIT. ...
In a position paper in EJPC by Hansen et al.,¹ authors provide detailed and interesting recommendations for cardiac rehabilitation providers concerning the design of exercise programme, one of which is that it should primarily be aimed at optimizing total energy expenditure rather than focusing on exercise intensity. However, we are still confused about how to match total energy expenditure between high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) in cardiac rehabilitation practice.
Despite the priority given to total energy expenditure in this article, exercise intensity remains a key issue in prescribing exercise. Although energy supplies (aerobic and anaerobic energy) and activations of muscle fibres (type I, IIA, and IIB) during almost all exercise activities are not exclusive, there are dominant energy supplies and muscle fibre recruitments with their own attributes in different training zones divided by the first and second ventilation threshold, eliciting in corresponding physiological responses, respectively (Figure 1A).² One of which is often overlooked that post-exercise metabolic responses to HIIT will remain elevated in an attempt to compensate for oxygen deficit driven by ‘high intensity’ during exercise.³ Consequently, HIIT may be underestimated despite matching total energy expenditure between HIIT and MICT with isocaloric protocols, which will potentially contribute to maximizing effect size of HIIT.
... HIIT is a truly time-efficient training modality in CR setting, which could assist to design a simplified exercise programme in Phase 2 CR. Aerobic threshold intensity, transition intensity, and anaerobic threshold intensity are derived from ventilatory threshold-based description of intensity levels during progressive exercise from rest to peak oxygen uptake by Li et al. 4 With increasing exercise intensity, Type I, IIA, and IIIB muscle fibres are activated at aerobic threshold intensity, transition intensity, and anaerobic threshold intensity, respectively, corresponding dominant energy requirements of which are aerobic energy, anaerobic glycolysis, and anaerobic phosphorylation. VT 1 , the first ventilatory threshold; VT 2 , the second ventilatory threshold; VO 2peak , peak oxygen uptake. ...
The paper by Qin et al. showed that high-intensity interval training (HIIT) could significantly improve peak oxygen uptake in post-MI （myocardial infarction） patients, and no significant difference in systolic and diastolic blood pressures, peak and resting heart rate, left ventricular ejection fraction, and left ventricular end-diastolic volume was found between HIIT group and control group.¹ Although its overall effectiveness in exercise capacity is often difficult to attribute to a single specific mechanism, compared with moderate-intensity continuous training and routine physical activity, it is speculated that HIIT’s potential for promoting gains in muscular strength may play an important role because of ‘high intensity’.
The persistent view of improving muscular strength is generally dominated by resistance-based training, which is recommended as the preferred type of exercise to improve muscle mass, cross-sectional area of muscle fibres (hypertrophy), and neural adaptations such as motor unit recruitment.² Although the activations of muscle fibres during almost all exercise activities are not exclusive, there are dominant recruitments of motor units with their own attributes in different training zones. The non-exclusivity also exists in energy supplies deriving from aerobic and anaerobic energy system. Exercise intensity above the first ventilatory threshold can elicit more contribution of anaerobic glycolytic energy, corresponding to the initial recruitment of Type IIA muscle fibres;³ similarly, exercise intensity above the second ventilation threshold can recruit Type IIB muscle fibres requiring immediate/high-energy adenosine triphosphate supply (Table 1). These high-threshold motor units are also recruited during resistance training. The greater activation of Type II muscle fibres is significantly related to the improvement of muscular strength. Therefore, HIIT can theoretically elicit muscle adaptations resembling resistance training.
... Likewise, the American College of Cardiology/American Heart Association strongly emphasizes the necessity of exercise individualization [6]. Many authors highlight in particular the need for more accurate tailoring of training intensity [1,[7][8][9]. ...
Introduction
It is unclear whether it is possible to determine the training load on the basis of the 6-minute walk test (6-MWT) in patients after cardiac surgery with low tolerance of physical exercise. Aim: Use of the 6-MWT to determine an individual initial training load in walking training on a treadmill in the early phase of cardiac rehabilitation in men after coronary artery bypass graft (CABG) surgery.
Material and methods
Twenty-two men aged 54 to 74 years, up to 3 months after CABG surgery participated in walking training on a treadmill (12–15 sessions). Patients underwent the initial and final treadmill exercise stress test (TEST) and the 6-MWT. Based on 6-MWT results, the initial training load was prescribed. Before the 6-MWT and 3 minutes after its completion, lactate concentration was determined.
Results
The 6-MWT distance increased from 420 ±80 m to 519 ±61 m (p < 0.001), and the energy expenditure from 4.4 ±1.4 MET to 6.3 ±1.3 MET (p < 0.001). There was a positive correlation between 6-MWT distance and energy expenditure in the TEST before rehabilitation (r = 0.60, p = 0.005), and after rehabilitation (r = 0.75, p < 0.001). A negative correlation was found between the baseline 6-MWT distance and distance increment in the final 6-MWT (r = –0.66, p = 0.002). The 6-MWT did not induce hyperlactatemia.
Conclusions
The 6-MWT can be used in exercise intensity prescription, especially for determining the individual initial training load, load progression, as well as its correction during follow-up tests.
Background and Aim : Despite progressive improvement in medical therapy and standard care, Exercisebased rehabilitation programs have been shown to to have beneficial cardiovascular effects in patients with myocardial infarction through a multifactorial effect. This review study aimed to evaluate exercise-based cardiac rehabilitation strategies in patients with myocardial infarction with special focus on high intensity interval training, as a growing field of research was conducted.
Material and Methods: This is a systematic review study on articles published, without limitation Year, by searching in reputable databases such as PabMed, Science Direct, Google Scholar, Scopus, Springer. Also in the process of searching for articles on the keywords microRNAs (miRNA) and myocardial infarction "," cardiac rehabilitation and myocardial infarction "," cardiac rehabilitation and high-intensity interval training (HIIT) ", high-intensity interval training (HIIT) and Myocardial infarction was used.
Ethical considerations: All Ethical principles in writing this article have been observed according to the instructions of the National Ethics Committee and the COPE regulations.
Results: High-intensity interval training (HIIT) is a safe and effective exercise strategy to improve cardiac function in MI, and to prevent abnormal changes in mass, size, geometry, and cardiac function after MI, and Applies significant changes in molecular targets and cell pathway.
Conclusion: Therefore, HIIT targets myocardial necroptosis due to oxidative stress, protects the heart against adverse left ventricular regeneration after MI, and can be considered an integral part of post-MI cardiac rehabilitation programs.
Exercise rehabilitation is highly recommended by current guidelines on prevention of cardiovascular disease, but its implementation is still poor. Many clinicians experience difficulties in prescribing exercise in the presence of different concomitant cardiovascular diseases and risk factors within the same patient. It was aimed to develop a digital training and decision support system for exercise prescription in cardiovascular disease patients in clinical practice: the European Association of Preventive Cardiology Exercise Prescription in Everyday Practice and Rehabilitative Training (EXPERT) tool.
Purpose: Evidence suggests considerable heterogeneity in exercise-induced changes in cardiorespiratory fitness and common cardiometabolic risk factors, with some individuals even experiencing adverse responses when exposed to regular exercise training. The purpose of this study was to compare the effectiveness of two exercise training programs for improving fitness and cardiometabolic health.
Methods: Sedentary men and women (n=46) performed 60-75 min/day, 3 days/wk for 13 wk according to one of two exercise training regimens: 1) a standardised program, or 2) an individualised program (ACE IFT).
Results: Maximal oxygen uptake (VO2max), body composition, systolic blood pressure (BP), and muscular fitness increased more favourably (p<0.05) in the ACE IFT treatment group. In the standardised treatment group 64.3% (9/14) of individuals experienced a favourable change in relative VO2max (Δ > +5.9%) and were categorised as responders. Alternatively, exercise training in the ACE IFT treatment group elicited a positive improvement in relative VO2max (Δ > +5.9%) in 100% (14/14) of the individuals. Furthermore, the incidence of anthropometric, cardiometabolic,and muscular fitness responders to exercise training were overall more favourable (p<0.05) in the ACE IFT treatment group: waist circumference (92.9% vs. 78.6%), percent body fat (100.0% vs. 78.6%), systolic BP (100.0%vs. 42.9%), HDL cholesterol (100.0% vs 50%), blood glucose(92.9% vs.42.9%), bench press 5-RM (100.0% vs 64.3%), and leg press 5-RM (100.0% vs 64.3%).
Conclusions: The major findings from the present study were as follows: 1) an individualised exercise prescription elicited significantly (p<0.05) greater improvements in VO2max, muscular fitness, and key cardiometabolic risk factors when compared to a standardised exercise prescription, and 2) an individualised exercise prescription increased training responsiveness when compared to a standardised exercise training program as evidenced by the significantly reduced (p<0.05) incidence of exercise training non-responders in the ACE IFT treatment group. These novel findings are encouraging and underscore the importance of a personalised exercise prescription to enhance training efficacy and limit training unresponsiveness.
Exercise intensity is arguably the most critical component of the exercise prescription model. It has been suggested that a threshold based model for establishing exercise intensity might better identify the lowest effective training stimulus for all individuals with varying fitness levels; however, experimental evidence is lacking. The purpose of this study was to compare the effectiveness of two exercise training programs for improving cardiorespiratory fitness: threshold based model vs. relative percent concept (i.e., % heart rate reserve - HRR).
Apparently healthy, but sedentary men and women (n = 42) were randomized to a non-exercise control group or one of two exercise training groups. Exercise training was performed 30 min/day on 5 days/week for 12weeks according to one of two exercise intensity regimens: 1) a relative percent method was used in which intensity was prescribed according to percentages of heart rate reserve (HRR group), or 2) a threshold based method (ACE-3ZM) was used in which intensity was prescribed according to the first ventilatory threshold (VT1) and second ventilatory threshold (VT2).
Thirty-six men and women completed the study. After 12weeks, VO2max increased significantly (p < 0.05 vs. controls) in both HRR (1.76 ± 1.93 mL/kg/min) and ACE-3ZM (3.93 ± 0.96 mL/kg/min) groups. Repeated measures ANOVA identified a significant interaction between exercise intensity method and change in VO2max values (F = 9.06, p < 0.05) indicating that VO2max responded differently to the method of exercise intensity prescription. In the HRR group 41.7 % (5/12) of individuals experienced a favorable change in relative VO2max (Δ > 5.9 %) and were categorized as responders. Alternatively, exercise training in the ACE-3ZM group elicited a positive improvement in relative VO2max (Δ > 5.9 %) in 100 % (12/12) of the individuals.
A threshold based exercise intensity prescription: 1). elicited significantly (p < 0.05) greater improvements in VO2max, and 2). attenuated the individual variation in VO2max training responses when compared to relative percent exercise training. These novel findings are encouraging and provide important preliminary data for the design of individualized exercise prescriptions that will enhance training efficacy and limit training unresponsiveness.
ClinicalTrials.gov Identifier: ID NCT02351713 Registered 30 January 2015.
Unlabelled:
The purpose of this study was to evaluate the effect of exercise training intensity relative to the ventilatory threshold (VT) on changes in work (watts) and VO2 at the ventilatory threshold and at maximal exercise in previously sedentary participants in the HERITAGE Family Study. We hypothesized that those who exercised below their VT would improve less in VO2 at the ventilatory threshold (VO2vt) and VO2max than those who trained at an intensity greater than their VT. Supervised cycle ergometer training was performed at the 4 participating clinical centers, 3 times a week for 20 weeks. Exercise training progressed from the HR corresponding to 55% VO2max for 30 minutes to the HR associated with 75% VO2max for 50 minutes for the final 6 weeks. VT was determined at baseline and after exercise training using standardized methods. 432 sedentary white and black men (n = 224) and women (n = 208), aged 17 to 65 years, were retrospectively divided into groups based on whether exercise training was initiated below, at, or above VT.
Results:
1) Training intensity (relative to VT) accounting for about 26% of the improvement in VO2vt (R2 = 0.26, p < 0.0001). 2) The absolute intensity of training in watts (W) accounted for approximately 56% of the training effect at VT (R2 = 0.56, p < 0.0001) with post-training watts at VT (VT(watts)) being not significantly different than W during training (p > 0.70). 3) Training intensity (relative to VT) had no effect on DeltaVO2max. These data clearly show that as a result of aerobic training both the VO2 and W associated with VT respond and become similar to the absolute intensity of sustained (3 x /week for 50 min) aerobic exercise training. Higher intensities of exercise, relative to VT, result in larger gains in VO2vt but not in VO2max.
The first part of this article intends to give an applicable framework for the evaluation of endurance capacity as well as for the derivation of exercise prescription by the use of two gas exchange thresholds: aerobic (AerTGE) and anaerobic (AnTGE). AerT GE corresponds to the first increase in blood lactate during incremental exercise whereas AnTGE approximates the maximal lactate steady state. With very few constraints, they are valid in competitive athletes, sedentary subjects, and patients. In the second part of the paper, the practical application of gas exchange thresholds in cross-sectional and longitudinal studies is described, thereby further validating the 2-threshold model. It is shown that AerTGE and AnTGE can reliably distinguish between different states of endurance capacity and that they can well detect training-induced changes. Factors influencing their relationship to the maximal oxygen uptake are discussed. Finally, some approaches of using gas exchange thresholds for exercise prescription in athletes, healthy subjects, and chronically diseased patients are addressed.
Secondary prevention through comprehensive cardiac rehabilitation has been recognized as the most cost-effective intervention to ensure favourable outcomes across a wide spectrum of cardiovascular disease, reducing cardiovascular mortality, morbidity and disability, and to increase quality of life. The delivery of a comprehensive and ‘modern’ cardiac rehabilitation programme is mandatory both in the residential and the out-patient setting to ensure expected outcomes. The present position paper aims to update the practical recommendations on the core components and goals of cardiac rehabilitation intervention in different cardiovascular conditions, in order to assist the whole cardiac rehabilitation staff in the design and development of the programmes, and to support healthcare providers, insurers, policy makers and patients in the recognition of the positive nature of cardiac rehabilitation. Starting from the previous position paper published in 2010, this updated document maintains a disease-oriented approach, presenting both well-established and more controversial aspects. Particularly for implementation of the exercise programme, advances in different training modalities were added and new challenging populations were considered. A general table applicable to all cardiovascular conditions and specific tables for each clinical condition have been created for routine practice.
Background
In the United Kingdom (UK), exercise intensity is prescribed from a fixed percentage range (% heart rate reserve (%HRR)) in cardiac rehabilitation programmes. We aimed to determine the accuracy of this approach by comparing it with an objective, threshold-based approach incorporating the accurate determination of ventilatory anaerobic threshold (VAT). We also aimed to investigate the role of baseline cardiorespiratory fitness status and exercise testing mode dependency (cycle vs. treadmill ergometer) on these relationships.
Design and methods
A maximal cardiopulmonary exercise test was conducted on a cycle ergometer or a treadmill before and following usual-care circuit training from two separate cardiac rehabilitation programmes from a single region in the UK. The heart rate corresponding to VAT was compared with current heart rate-based exercise prescription guidelines.
Results
We included 112 referred patients (61 years (59–63); body mass index 29 kg·m–2 (29–30); 88% male). There was a significant but relatively weak correlation (r = 0.32; p = 0.001) between measured and predicted %HRR, and values were significantly different from each other (p = 0.005). Within this cohort, we found that 55% of patients had their VAT identified outside of the 40–70% predicted HRR exercise training zone. In the majority of participants (45%), the VAT occurred at an exercise intensity <40% HRR. Moreover, 57% of patients with low levels of cardiorespiratory fitness achieved VAT at <40% HRR, whereas 30% of patients with higher fitness achieved their VAT at >70% HRR. VAT was significantly higher on the treadmill than the cycle ergometer (p < 0.001).
Conclusion
In the UK, current guidelines for prescribing exercise intensity are based on a fixed percentage range. Our findings indicate that this approach may be inaccurate in a large proportion of patients undertaking cardiac rehabilitation.
To investigate the relationships between oxygen consumption (VO2) and the rates of systemic lactate appearance (Ra) and disappearance (Rd), six healthy males were studied at rest and during continuous graded exercise using a primed continuous infusion of lactate tracer. Subjects exercised for 6 min at 300, 600, 900, and 1,200 kg . m . min-1. L-(+)-[1-14C]lactate was infused intravenously, and arterial samples were drawn at rest and every 2 min throughout the exercise period. Ra and Rd were calculated using nonsteady-state equations. At rest Ra and Rd were 14.4 +/- 1.8 and 15.1 +/- 2.2 mumol . kg-1 . min-1, respectively. Near steady-state values were observed toward the end of the first two work loads. Ra and Rd values were 32.8 +/- 2.3 and 37.4 +/- 1.3 mumol . kg-1 . min-1 during min 5 and 6 at 300 kg . m . min-1 and were 59.1 +/- 2.6 and 55.4 +/- 2.3 mumol . kg-1 . min-1 during min 5 and 6 at 600 kg . m . min-1. Ra was significantly greater than Rd at both 900 and 1,200 kg . m . min-1. Ra and Rd averaged 145.4 +/- 10.5 and 110.2 +/- 5.6 mumol . kg-1 . min-1, respectively, during the last 2 min at 900 kg . m . min-1, and 309.4 +/- 20.8 and 169.7 +/- 10.6 mumol . kg-1 . min-1, respectively, at 1,200 kg . m . min-1.(ABSTRACT TRUNCATED AT 250 WORDS)
In the past several decades, cardiopulmonary exercise testing (CPX) has seen an exponential increase in its evidence base. The growing volume of evidence in support of CPX has precipitated the release of numerous scientific statements by societies and associations. In 2012, the European Association for Cardiovascular Prevention & Rehabilitation and the American Heart Association developed a joint document with the primary intent of redefining CPX analysis and reporting in a way that would streamline test interpretation and increase clinical application. Specifically, the 2012 joint scientific statement on CPX conceptualized an easy-to-use, clinically meaningful analysis based on evidence-vetted variables in color-coded algorithms; single-page algorithms were successfully developed for each proposed test indication. Because of an abundance of new CPX research in recent years and a reassessment of the current algorithms in light of the body of evidence, a focused update to the 2012 scientific statement is now warranted. The purposes of this update are to confirm algorithms included in the initial scientific statement not requiring revision, to propose revisions to algorithms included in the initial scientific statement, to propose new algorithms based on emerging scientific evidence, to further clarify the application of oxygen consumption at ventilatory threshold, to describe CPX variables with an emerging scientific evidence base, to describe the synergistic value of combining CPX with other assessments, to discuss personnel considerations for CPX laboratories, and to provide recommendations for future CPX research.
Thresholds in cardiopulmonary exercise testing are necessary for the evaluation of motivation and cooperation in exercise, for training programs, in transplant medicine, preoperative evaluation and medical assessments. There is a hardly comprehensible number of terminologies concerning these thresholds and their definitions. This hampers the comparison of protocols and studies and leads to incertainties in terminologies and interpretations of cardiopulmonary exercise tests. Based on literature a definition of thresholds was undertaken. Thresholds should be regarded from a conceptional and an operational (methodological) point of view. The conceptional model means, that there are two ventilatory thresholds (VT1 and VT2) and two metabolic thresholds (lactate threshold [LT] 1 and 2 ). These thresholds are pathophysiologically based. Both threshold concepts determinate the beginning and the end of the aerobic-anaerobic transition. The lactate thresholds determine the metabolic changes, whereas the ventilator thresholds 1 and 2 represent the ventilatory response to the metabolic changes. VT1 represents the subsequent increase of ventilation and CO2-output relative to oxygen uptake as a consequence of an increase of lactate and a necessary lactate buffering. VT2 is characterized by an exceeding of lactate-steady-state, resulting in excess lactate, metabolic acidosis and overproportional rise of ventilation. The operational concept describes the method, which is used for determination of the different lactate and ventilatory thresholds. In a further step this can be completed by indicating the exercise protocol which was applied.
© Georg Thieme Verlag KG Stuttgart · New York.
Determination of an 'anaerobic threshold' plays an important role in the appreciation of an incremental cardiopulmonary exercise test and describes prominent changes of blood lactate accumulation with increasing workload. Two lactate thresholds are discerned during cardiopulmonary exercise testing and used for physical fitness estimation or training prescription. A multitude of different terms are, however, found in the literature describing the two thresholds. Furthermore, the term 'anaerobic threshold' is synonymously used for both, the 'first' and the 'second' lactate threshold, bearing a great potential of confusion. The aim of this review is therefore to order terms, present threshold concepts, and describe methods for lactate threshold determination using a three-phase model with reference to the historical and physiological background to facilitate the practical application of the term 'anaerobic threshold'.
Anaerobic and aerobic-anaerobic threshold (4 mmol/l lactate), as well as maximal capacity, were determined in seven cross country skiers of national level. All of them ran in a treadmill exercise for at least 30 min at constant heart rates as well as at constant running speed, both as previously determined for the aerobic-anaerobic threshold. During the exercise performed with a constant speed, lactate concentration initially rose to values of nearly 4 mmol/l and then remained essentially constant during the rest of the exercise. Heart rate displayed a slight but permanent increase and was on the average above 170 beats/min. A new arrangement of concepts for the anaerobic and aerobic-anaerobic threshold (as derived from energy metabolism) is suggested, that will make possible the determination of optimal work load intensities during endurance training by regulating heart rate.
To investigate the relationships between oxygen consumption (VO2) and the rates of systemic lactate appearance (Ra) and disappearance (Rd), six healthy males were studied at rest and during continuous graded exercise using a primed continuous infusion of lactate tracer. Subjects exercised for 6 min at 300, 600, 900, and 1,200 kg . m . min-1. L-(+)-[1-14C]lactate was infused intravenously, and arterial samples were drawn at rest and every 2 min throughout the exercise period. Ra and Rd were calculated using nonsteady-state equations. At rest Ra and Rd were 14.4 +/- 1.8 and 15.1 +/- 2.2 mumol . kg-1 . min-1, respectively. Near steady-state values were observed toward the end of the first two work loads. Ra and Rd values were 32.8 +/- 2.3 and 37.4 +/- 1.3 mumol . kg-1 . min-1 during min 5 and 6 at 300 kg . m . min-1 and were 59.1 +/- 2.6 and 55.4 +/- 2.3 mumol . kg-1 . min-1 during min 5 and 6 at 600 kg . m . min-1. Ra was significantly greater than Rd at both 900 and 1,200 kg . m . min-1. Ra and Rd averaged 145.4 +/- 10.5 and 110.2 +/- 5.6 mumol . kg-1 . min-1, respectively, during the last 2 min at 900 kg . m . min-1, and 309.4 +/- 20.8 and 169.7 +/- 10.6 mumol . kg-1 . min-1, respectively, at 1,200 kg . m . min-1.(ABSTRACT TRUNCATED AT 250 WORDS)
Alterations in gas exchange were studied in man during exercise increasing in increments of 5 w each minute, to determine the noninvasive indicators of the onset of metabolic acidosis (anaerobic metabolism). Expired airflow and CO2 and O2 tensions at the mouth during the breath were continuously monitored with rapidly responding gas analyzers. These measurements were recorded directly as well as processed by a minicomputer, on line, to give minute ventilation (VE), CO2 production (VCO2), O2 consumption (VO2), and the gas exchange ratio (R), breath by breath. The anaerobic threshold (AT) could be identified by the point of nonlinear increase in VE, nonlinear increase in VCO2, an increase in end tidal O2 without a corresponding decrease in end tidal CO2, and an increase in R, as work rate was increased during an incremental exercise test. Of these measurements, R was found least sensitive. The AT was determined in 85 normal subjects between 7 and 91 yr of age, by these techniques. The lower limit of normal was 45 w (VO2 = 1 liter/min) while values for very fit normal adults were as high as 180 w. The patients studied with cardiac disease above functional class I have lower anaerobic thresholds than the least fit normal subjects. The 1 min incremental work rate test is associated with changes in gas exchange which can be used as sensitive on line indicators of the AT, thus bypassing the need for measuring arterial lactate or acid base parameters to indicate anaerobiosis.
Positional paper of the German Working Group “Cardiopulmonary Exercise Testing” to ventilatory and metabolic (lactate) thresholds
- M Westhof
- KH Rühle
- A Greiwing
Does a personalised exercise prescription enhance training efficacy and limit training unresponsiveness? A randomized controlled trial
- L C Dalleck
- Haney
- De
- C A Buchanan
Anaerobic threshold and respiratory gas exchange during exercise
- K Wasserman
- B J Whipp
- S N Koyal
Wasserman K, Whipp BJ, Koyal SN, et al. Anaerobic
threshold and respiratory gas exchange during exercise.
J Appl Physiol 1973; 35: 236-243.
Positional paper of the German Working Group “Cardiopulmonary Exercise Testing” to ventilatory and metabolic (lactate) thresholds
- Westhof