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Heart rate variability in women exposed to very cold air (−110 °C) during whole-body cryotherapy

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Abstract

Heart rate monitoring was used to measure heart rate variability (HRV) at thermoneutral conditions (Ta 24°C) in healthy women resting in supine position before and after acute and after repeated (3 times a week during a 3-month period) whole-body cryotherapies (WBC), at −110°C. The observed acute cooling-related increase in high frequency power (HFP) of RR-intervals indicates an increase in cardiac parasympathetic modulation. After 3 months of repeated WBC the increase in parasympathetic tone was attenuated, which may be interpreted as an adaptation of autonomic function. The repeated WBC exposures-related increase in resting low frequency power (LFP) of RR-intervals during the 3 months resembles the response observed related to exercise training.

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... nitrogen or atmospheric air. Despite employing thermal stimulation that utilize very low temperatures, (from À100°C to À170°C), when performed properly the procedure is not associated with risk of side effects, such as frostbite or other injuries to the skin [4][5][6]. WBC is mostly used as a procedure to relieve pain symptoms, inflammatory condition, acute injures soft tissue rheumatic disease, neurodegenaritve conditions and depressive and anxiety disorders. This method is also very popular for wellness treatment and athletic recovery [1,2,7,8]. ...
... Our findings confirmed that WBC has a very strong impact on cutaneous vascular changes which lead to displace blood from cutaneous vessels into deep veins and results in systemic hemodynamic changes observed briefly after exposure [6,9,29,30]. ...
... It is well known that tachycardia occurs after acute local cooling, e.g., a cold pressor test [15,31], but bradycardia is present even after mild whole-body cooling [30,32]. The increase in ventricular filling as well as the flow of chilled peripheral blood into the area of atrial sinus node resulted in a significant decrease in heart rate, such a mechanism has been also confirmed by other authors [4,6,9,10]. ...
Article
Whole-body cryotherapy (WBC) is an increasing applied cryotherapeutic method, that involves application of a cryotherapeutic factor to stimulate the body by the means of intense hypothermia of virtually the body’s entire area. This method is still not well recognized in Western Europe. However in recent years it is becoming increasingly popular in sports medicine and also in clinical application.Cryotherapeutic agents used in WBC are considered to be a strong stress stimulus which is associated with a variety of changes in functional parameters, particularly of the cardiovascular and autonomic nervous systems. However, such strong influence upon the entire body could be associated with the risk of unexpected reactions which might be dangerous for homeostasis. The present study evaluated the complex hemodynamic physiological reactions in response to WBC exposure in healthy subjects. Thirty healthy male volunteers participated. Each subject was exposed to WBC (−120°C) for 3-min. None of the participants had been exposed to such conditions previously. The research was conducted with modern and reliable measurements techniques, which assessed complex hemodynamic reactions and skin temperature changes non-invasively. All measurements were performed four times (before WBC, after WBC, WBC + 3 h and WBC + 6 h) with a Task Force Monitor (TFM – CNSystems, Medizintechnik, Gratz, Austria). Body superficial temperature was measured by infrared thermographic techniques – infra-red camera Flir P640 (Flir Systems Inc., Sweden). Our results show a significant decrease in heart rate, cardiac output, and increase in stroke volume, total peripheral resistance and baroreceptors reflex sensitivity. These changes were observed just after WBC exposure. At stages WBC + 3 h and WBC + 6 h there was observed a significant drop in baroreceptors reflex sensitivity due to increased thermogenesis. In conclusion, the present findings suggest that WBC strongly stimulates the baroreceptor cardiac reflex in response to body fluid changes which sequentially modulate HR and BP control in supine and resting healthy subjects. The study was performed on randomized and homogenic group of young healthy subjects. Our findings are important for WBC safety determination in research and clinical studies.
... nitrogen or atmospheric air. Despite employing thermal stimulation that utilize very low temperatures, (from À100°C to À170°C), when performed properly the procedure is not associated with risk of side effects, such as frostbite or other injuries to the skin [4][5][6]. WBC is mostly used as a procedure to relieve pain symptoms, inflammatory condition, acute injures soft tissue rheumatic disease, neurodegenaritve conditions and depressive and anxiety disorders. This method is also very popular for wellness treatment and athletic recovery [1,2,7,8]. ...
... Our findings confirmed that WBC has a very strong impact on cutaneous vascular changes which lead to displace blood from cutaneous vessels into deep veins and results in systemic hemodynamic changes observed briefly after exposure [6,9,29,30]. ...
... It is well known that tachycardia occurs after acute local cooling, e.g., a cold pressor test [15,31], but bradycardia is present even after mild whole-body cooling [30,32]. The increase in ventricular filling as well as the flow of chilled peripheral blood into the area of atrial sinus node resulted in a significant decrease in heart rate, such a mechanism has been also confirmed by other authors [4,6,9,10]. ...
... Such reaction stimulates baroreceptors and leads to a diminution of the sympathetic nerve activity and an increase in vagal control of the myocardium (Zalewski et al. 2013). As such, it is well established that WBC is effective in increasing post-exercise and resting heart rate variability (HRV), an indicator of increased parasympathetic tone activation (Westerlund et al. 2006;Schaal et al. 2013;Hausswirth et al. 2013;Zalewski et al. 2014). ...
... These authors found a larger decrease in mean skin temperature after WBC and associated it with a stronger stimulation of the ANS, especially of the parasympathetic tone. Several studies also demonstrated that acute exposure to WBC at temperatures ranging from − 60 to − 120 °C significantly increased the parasympathetic activity (Westerlund et al. 2006;Zalewski et al. 2014;Douzi et al. 2018). In the present study, the effects of WBC on HRV indices of parasympathetic activity were similar after one and five exposures. ...
Article
Full-text available
PurposeA predominance of parasympathetic drive is observed following cold exposure. Such modulation of the autonomic nervous system (ANS) is associated with faster post-exercise recovery. Within this context, whole-body cryotherapy (WBC) has been spreading in sport medicine, though the optimal temperature and frequency are unclear. The aim of this study was to examine the effects of different cryotherapy conditions on the sympathovagal balance.Methods Forty healthy males were randomly assigned into five different groups (− 110 °C, − 60 °C, − 10 °C, control temperature [≃ 24 °C]) and undertook 5 WBC sessions over 5 consecutive days. Cardiac autonomic activity was assessed through heart rate variability (HRV) using power density of high frequency (HF), root-mean square difference of successive R–R intervals (RMSSD) and sympathovagal balance (LF/HF). Systemic sympathetic activity was assessed via circulating blood catecholamines.ResultsMean weekly RMSSD (pre: 48 ± 22 ms, post: 68 ± 29 ms) and HF (pre: 607 ± 692 ms2, post: 1271 ± 1180 ms2) increased (p < 0.05) from pre to post WBC, only in the − 110 °C condition. A rise in plasma norepinephrine was found after the first − 110 °C WBC session only (pre: 173 ± 98, post: 352 ± 231 ng L−1, p < 0.01); whereas, it was not significant after the 5th session (pre: 161 ± 120, post: 293 ± 245 ng L−1, p = 0.15).Conclusion These results suggest that one − 110 °C WBC exposure is required to stimulate the ANS. After five daily exposures, a lower autonomic response was recorded compared to day one, therefore suggesting the development of physiological habituation to WBC.
... Also the significant changes of systolic time parameters, i.e. left ventricular ejection time (LVET) and pre-ejection period (PEP), pointed to a greater filling of heart chambers in both the analyzed groups [34]. Our findings regarding the post-exposure changes in heart rate (HR) are consistent with reports from other authors, and point to an evident negative chronotropic effect of cryostimulation [19,20,18,33,32,24]. However, the opposite phenomenon, i.e. an increase in heart rate after rapid cooling to the body, was reported by some other authors; this was explained as a consequence of enhanced stimulation of b-adrenergic receptors, and resultant increase in the sympathetic activity. ...
... In contrast, a decrease in all three blood pressure parameters was observed in the hypertensive individuals; this phenomenon should not be interpreted as a result of increased activity of baroreceptors, as the sensitivity of the latter was already lower at baseline and its relative increase was less evident than in the normotensive subjects. The decrease in blood pressure parameters of this group likely reflected weakening of compensatory mechanisms, a reason behind development of primary arterial hypertension [16,18,17,33,21,24]. ...
Article
Over recent years, a considerable increase in the popularity of cryostimulation and whole body cryotherapy (WBC) procedures has occurred both among healthy individuals and in various groups of patients, including those with primary untreated hypertension. The aim of this study was to compare the effects of WBC on the functional parameters of cardiovascular system in normotensive and primarily hypertensive individuals. The study included 26 young male volunteers with normal blood pressure range (NormoBP) and 13 with essential arterial hypertension (HyperBP). Each subject was exposed to cryotherapeutic factor (whole-body cryotherapy/cryostimulation, WBC) at a temperature of approximately - 115°C to -125°C for a peroid of 3 minutes. The cardiovascular and autonomatic paramaters were measured noninvasively with Task Force® Monitor. Measurements in a supine position and tilt test were performed "before WBC" and "after WBC". Our study revealed that cryogenic temperatures exert strong modulatory effect on the cardiovascular system. Both groups showed adaptive changes of myocardial and vascular parameters in response to rapid cooling of virtually the whole body surface. While the profiles of some of these changes were similar in both the groups, also several considerable intergroup differences were documented. Consequently, the cryostimulation and cryotherapy treatment should be prescribed carefully to individuals who present with cardiovascular failure of any degree.
... Only one study reported a significant increase in the heat rate variability (HRV) indices of parasympathetic activity following a WBC session performed after exercise in elite synchronized swimmers [12]. Similarly, in resting conditions, Westerlund et al. [24] found that a single session of WBC significantly augmented HRV indices of parasympathetic modulation in healthy nonathletic women, with a mean increase of approximately 50% in RMSSD and high frequency power. Cold exposure has been found to suppress cardiac sympathetic activity and increase parasympathetic output as a result of arterial baroreflex activation [25]. ...
... HF: +138%) (Figure 5). Increases in HRV indices of parasympathetic activity were previously observed after a single WBC session at -110°C in non-athletic women (RMSSD: +53%) [24] and in elite synchronized swimmers (RMSSD: +78%; HF: +296%) [12]. Cold water immersion (5-min in 11 to 14°C) was also shown to increase RMSSD and HF values but in lower proportions compared to WBC181920. ...
Article
Full-text available
The aim of this study was to compare the effects of a single whole-body cryostimulation (WBC) and a partial-body cryostimulation (PBC) (i.e., not exposing the head to cold) on indices of parasympathetic activity and blood catecholamines. Two groups of 15 participants were assigned either to a 3-min WBC or PBC session, while 10 participants constituted a control group (CON) not receiving any cryostimulation. Changes in thermal, physiological and subjective variables were recorded before and during the 20-min after each cryostimulation. According to a qualitative statistical analysis, an almost certain decrease in skin temperature was reported for all body regions immediately after the WBC (mean decrease±90% CL, -13.7±0.7°C) and PBC (-8.3±0.3°C), which persisted up to 20-min after the session. The tympanic temperature almost certainly decreased only after the WBC session (-0.32±0.04°C). Systolic and diastolic blood pressures were very likely increased after the WBC session, whereas these changes were trivial in the other groups. In addition, heart rate almost certainly decreased after PBC (-10.9%) and WBC (-15.2%) sessions, in a likely greater proportion for WBC compared to PBC. Resting vagal-related heart rate variability indices (the root-mean square difference of successive normal R-R intervals, RMSSD, and high frequency band, HF) were very likely increased after PBC (RMSSD: +54.4%, HF: +138%) and WBC (RMSSD: +85.2%, HF: +632%) sessions without any marked difference between groups. Plasma norepinephrine concentrations were likely to very likely increased after PBC (+57.4%) and WBC (+76.2%), respectively. Finally, cold and comfort sensations were almost certainly altered after WBC and PBC, sensation of discomfort being likely more pronounced after WBC than PBC. Both acute cryostimulation techniques effectively stimulated the autonomic nervous system (ANS), with a predominance of parasympathetic tone activation. The results of this study also suggest that a whole-body cold exposure induced a larger stimulation of the ANS compared to partial-body cold exposure.
... However, thanks to a very cold stimulus, WBC could induce larger parasympathetic activation than cold water immersion [15]. Accordingly, significant increases in heart rate variability (HRV) indices of parasympathetic activity (the root-mean square difference of successive normal R-R intervals, RMSSD, and high frequency band, HF) have been reported after a WBC session performed as well after exercise in elite synchronized swimmers [15] as in healthy nonathletic women [16]. More recently, in a study from our team, we also recorded a significant increase in parasympathetic activity within the 20-min following a single WBC session performed without previous exercise, as inferred through an increase in HF and RMSSD concomitant to a decrease in HR [13]. ...
... Elevated parasympathetic activity at rest is classically associated with health and well-being, and is enhanced by regular physical activity and more generally by a healthy lifestyle, including balanced diet, no smoking and no alcohol [44]. Body exposure to cold is an effective method to increase parasympathetic activity easily and rapidly and greater effects are obtained by using air-based cryotherapy protocols [13,15,16] than cold water immersion [9,10,45]. ...
Article
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Recent research on whole-body cryotherapy has hypothesized a major responsibility of head cooling in the physiological changes classically reported after a cryostimulation session. The aim of this experiment was to verify this hypothesis by studying the influence of exposing the head to cold during whole-body cryostimulation sessions, on the thermal response and the autonomic nervous system (ANS). Over five consecutive days, two groups of 10 participants performed one whole-body cryostimulation session daily, in one of two different systems; one exposing the whole-body to cold (whole-body cryostimulation, WBC), and the other exposing the whole-body except the head (partial-body cryostimulation, PBC).10 participants constituted a control group (CON) not receiving any cryostimulation. In order to isolate the head-cooling effect on recorded variables, it was ensured that the WBC and PBC systems induced the same decrease in skin temperature for all body regions (mean decrease over the 5 exposures: -8.6°C±1.3°C and -8.3±0.7°C for WBC and PBC, respectively), which persisted up to 20-min after the sessions (P20). The WBC sessions caused an almost certain decrease in tympanic temperature from Pre to P20 (-0.28 ±0.11°C), while it only decreased at P20 (-0.14±0.05°C) after PBC sessions. Heart rate almost certainly decreased after PBC (-8.6%) and WBC (-12.3%) sessions. Resting vagal-related heart rate variability indices (the root-mean square difference of successive normal R-R intervals, RMSSD, and high frequency band, HF) were very likely to almost certainly increased after PBC (RMSSD:+49.1%, HF: +123.3%) and WBC (RMSSD: +38.8%, HF:+70.3%). Plasma norepinephrine concentration was likely increased in similar proportions after PBC and WBC, but only after the first session. Both cryostimulation techniques stimulated the ANS with a predominance of parasympathetic tone activation from the first to the fifth session and in slightly greater proportion with WBC than PBC. The main result of this study indicates that the head exposure to cold during whole-body cryostimulation may not be the main factor responsible for the effects of cryostimulation on the ANS.
... 18 The range of change depends on both BMI 14,18 and gender. 19,20,21 Core and muscle temperatures hardly drop during WBC. 16,18 As we will demonstrate below, WBC has been applied within various fields that mainly focus on the somatic benefits of the procedure. ...
... For example none of the included studies differentiated in its results according to participant's gender, while the literature shows that female bodies are cooling down in a different and quicker way than male bodies do. [19][20][21] The same goes for differences of BMI among participants, or whether participants were moving or not inside the cold-chamber. Both factors are known to influence the degree of cooling down the skin and thereby potentially influence effects of WBC. ...
Article
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Objective To give an overview of the nature and methodological quality of studies on whole body cryotherapy (WBC) as add-on intervention for mental health problems. Methods A meta-analysis according to PRISMA guidelines was conducted (Prospero registration: CRD42020167443). Databases MEDLINE, PsycINFO and the Cochrane Library were searched. Risk of bias was scored according to the Cochrane ROBINS-I-tool to which an extra bias-dimension of allegiance bias was added. Within and between Hedges’ g pooled effect sizes were calculated for the main aspect of mental health measured. Treatment efficacy was examined using a random effects model. Heterogeneity was examined through identification of visual outliers and by I² statistics. Results Out of 196 articles coming up from the search, ten studies met all inclusion criteria, six of which were (randomized) controlled trials. Together these studies report on a total of 294 participants receiving WBC. The within-group pooled effect size for mental health problems is large (Hedges’ g = 1.63, CI: 1.05-2.21), with high heterogeneity (I² = 93%). Subgroup analyses on depressive symptoms and quality of life (QOL) showed a diminution of heterogeneity to moderate. Effect sizes for depressive symptoms are very large (Hedges’ g = 2.95, CI: 2.44-3.45) and for QOL medium (Hedges’ g = 0.70, CI: 0.15-1.24). The between-group pooled effect size is medium (Hedges’ g = 0.76, CI: 0.17-1.36). Conclusions Results indicate preliminary evidence for WBC as efficacious add-on intervention for mental health problems, especially depressive symptoms. Further research in the form of RCTs with larger numbers of participants is needed.
... A significant decrease in heart rate was most evident in the cardiovascular response to cryogenic stimulation observed in our participants. This finding is consistent with the results published by other authors (Bonomi et al., 2012;Lubkowska and Szygula, 2010;Westerlund et al., 2006). Two mechanisms could be Table 3 Resting values of heart rate and blood pressure variability parameters in the study group; n indicates significant differences between the pre-and post-treatment parameters; all data are expressed as mean 7 standard deviations, and P values (abbreviations are listed in Section 1). ...
... The significant decrease in total power spectral density (PSD-RRI) at further stages of our study can be interpreted as a consequence of decrease in the activity of both sympathetic and parasympathetic component. The results of spectral analysis of HRV were in line with the changes of HR, sBP, dBP, mBP and BRS observed during consecutive stages of our experiment, and the relationships documented herein were previously reported by other authors (Mäkinen et al., 2008;Westerlund et al., 2004Westerlund et al., , 2006. ...
Article
The cardiovascular, autonomic and thermal response to whole-body cryostimulation exposure are not completely known. Thus the aim of this study was to evaluate objectively and noninvasively autonomic and thermal reactions observed after short exposure to very low temperatures. We examined 25 healthy men with mean age 30.1±3.7 years and comparable anthropomorphical characteristic. Each subject was exposed to cryotherapeutic temperatures in a cryogenic chamber for 3 minutes (approx. - 120oC). The cardiovascular and autonomic parameters were measured noninvasively with Task Force® Monitor. The changes in core body temperature were determined with the Vital Sense® telemetric measurement system. Results show that 3 minutes to cryotherapeutic temperatures causes significant changes in autonomic balance which are induced by peripheral and central blood volume changes. Cryostimulation also induced changes in core body temperature, maximum drop of core temperature was observed 50–60 min after the stimulation. Autonomic and thermal reactions to cryostimulation were observed up to 6 hours after the exposure and were not harmful for examined subjects.
... The augmentation of pre-exercise HRV values observed in synchronized swimmers after WBC reflects a strong parasympathetic reactivation at the cardiac level, with values largely surpassing those measured at rest as early as 60 min after maximal exercise. To our knowledge, this was the first study to describe such a large increase in vagal-related HRV indices from any cold exposure recovery technique used after exercise, with mean increases ranging from 78% for rMSSD and 140% for SD1 to 296% for HF. Westerlund et al. (2006) investigated the HRV response to WBC in the resting state in nonathletic women, and reported that 2 min of WBC (−110 °C) augmented HRV indices of parasympathetic activity by 53% for rMSSD and 47% for SD1. In the case of highly trained swimmers, we showed that this significant effect of WBC occurred even when the treatment was performed shortly after maximal exercise, in a context of heightened cardiac sympathetic activity and suppressed vagal tone. ...
Article
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This study investigated the effect of whole-body cryostimulation (WBC), contrast-water therapy (CWT), active recovery (ACT), and passive condition (PAS) protocols on the parasympathetic reactivation and metabolic parameters of recovery in elite synchronized swimmers who performed 2 simulated competition ballets (B1 and B2) separated by 70 min. After determining maximal oxygen consumption (V̇O(2max400)) and blood lactate concentrations ([La(-)](b400)) during a 400-m swim trial, 11 swimmers performed 1 protocol per week in randomized order. Heart rate variability (HRV) was measured at rest (PreB1), 5 min after B1 (PostB1), before B2 (PreB2), and 5 min after B2 (PostB2). V̇O(2peak) was measured at PostB1 and PostB2, and [La(-)](b) was measured at PostB1, PreB2, and PostB2. PostB1 V̇O(2peak) and V̇O(2max400) were similar, but PostB1 [La(-)](b) was higher than [La(-)](b400) (p = 0.004). Each ballet caused significant decreases in HRV indices. At PreB2, all HRV indices had returned to PreB1 levels in the CWT, PAS, and ACT protocols, whereas the WBC protocol yielded a 2- to 4-fold increase in vagal-related HRV indices, compared with PreB1. WBC and ACT both increased [La(-)](b) recovery, compared with PAS (p = 0.06 and p = 0.04, respectively), and yielded an increased V̇O(2peak) from B1 to B2; however, it decreased after PAS (+5.4%, +3.4%, and -3.6%; p < 0.01). This study describes the physiological response to repeated maximal work bouts that are highly specific to elite synchronized swimming. In the context of short-term recovery, WBC yields a strong parasympathetic reactivation, and shows similar effectiveness to ACT on the metabolic parameters of recovery and subsequent exercise capacity.
... To our knowledge, this was the first study to describe such a large increase in vagal-related HRV indices from any cold exposure recovery technique used after exercise, with mean increases ranging from 78% for rMSSD and 140% for SD1 to 296% for HF. Westerlund et al. (2006) investigated the HRV response to WBC in the resting state in nonathletic women, and reported that 2 min of WBC (−110°C) augmented HRV indices of parasympathetic activity by 53% for rMSSD and 47% for SD1. In the case of highly trained swimmers, we showed that this significant effect of WBC occurred even when the treatment was performed shortly after maximal exercise, in a context of heightened cardiac sympathetic activity and suppressed vagal tone. ...
Article
Full-text available
Introduction: This study investigated the effect of whole-body cryostimulation (WBC), contrast-water therapy (CWT), active (ACT) and passive (PAS) protocols on parasympathetic reactivation and metabolic parameters of recovery in elite synchronized swimmers performing two simulated competition ballets (B1 and B2) separated by 70 minutes. Methods: After determining maximal oxygen consumption (VO2max400) and blood lactate concentrations ([La-]b400) during a 400m swim trial, 11 swimmers performed one trial per week, in randomized order. Heart rate variability (HRV) was measured at rest (PreB1), 5 minutes after B1 (PostB1), before B2 (PreB2), and 5 minutes after B2 (PostB2).VO2peak was measured at PostB1 and PostB2, and [La-]b at PostB1, PreB2, and PostB2. Results: PostB1 and PostB2 VO2peak values were similar to VO2max400, but [La-]b PostB1 and PostB2 were higher than [La-]b400. Each ballet caused significant decreases in rMSSD, SD1, HF and LF. At PreB2, all HRV indices had returned to PreB1 values with CWT, PAS, and ACT, while WBC yielded a 2 to 4-fold increase in vagal-related HRV indices (rMSSD, SD1) compared to PreB1. WBC and ACT both increased [La-]b recovery compared to PAS, and yielded an increased VO2peak from B1 to B2, while it decreased after PAS (+5.4%, +3.4%, and -3.6%, p < 0.01). Conclusion: This study describes the physiological response to repeated maximal work bouts that are highly specific to elite synchronized swimming. In the context of short-term recovery, WBC yields a strong parasympathetic reactivation, and shows similar effectiveness as ACT on metabolic parameters of recovery and subsequent exercise capacity.
... The study of Lan et al. showed that heart rates were consistently lower at 22 C than at 30 C [10]. Westerlund et al. performed human subject experiments with ten female volunteers and reported that heart rates increased in cold environments [11]. Thus, multiple researchers have reported heart rate variances at different thermal conditions. ...
Data
a b s t r a c t According to the current thermal comfort theory, metabolic rate and clothing insulation are critical human factors that affect thermal sensation. Since heart rate is significantly correlated with human metabolic rate, it may undoubtedly be a potential parameter that directly (or indirectly) impacts the principle of thermal comfort. In addition, even though a few researchers have identified an insignificant relationship between heart rate and thermal conditions, many have reported heart rate variability at different thermal sensation levels based on the principle of thermoregulation. However, in spite of its potential as a thermal sensation effector, as well as an indicator, current thermal comfort models have focused mainly on several local body skin temperatures and the core body temperature without considering heart rate. Therefore, this research has relied on experiments with human subjects in two environmental chambers (each with a different thermal condition) to investigate and determine whether and how the heart rate during the same activity level is affected by warm and cold conditions. It also sought to determine how heart rate is related to thermal sensation, and whether the effect would vary depending on gender and body mass index. Results of this study revealed that the heart rate and the changes in rates that occurred between different activity levels showed a significant increase during warm conditions, with a 2.5 metabolic rate, especially in males and in body mass index groups higher than 22. A decent increase in the change rates was also found at 1.0 Met, as compared with 0.8 Met.
... The results also explained the subjects' complaints that they had a sensation of pain at the first minute of the cold stimulus and subsequently the pain disappeared after the cold adaptation. In addition, some other studies reported that sympathetic activation response to the cold pressor test was blunted after adaptation of cold exposure training (Makinen et al 2008, Brandstrom et al 2013 and that whole-body cryotherapies had similar effect on the autonomic system compared to exercise training (Westerlund et al 2006). We thus speculate that features of the sympathetic peaks like the vertex and the offset might be related to the adaptability of the subjects. ...
Article
Full-text available
Heart rate variability is a useful clinical tool for autonomic function assessment and cardiovascular disease diagnosis. To investigate the dynamic changes of sympathetic and parasympathetic activities during the cold pressor test, we used a time-varying autoregressive model for the time-frequency analysis of heart rate variability in 101 healthy subjects. We found that there were two sympathetic peaks (or two parasympathetic valleys) when the abrupt changes of temperature (ACT) occurred at the beginning and the end of the cold stimulus and that the sympathetic and parasympathetic activities returned to normal in about the last 2 min of the cold stimulus. These findings suggested that the ACT rather than the low temperature was the major cause of the sympathetic excitation and parasympathetic withdrawal. We also found that the onsets of the sympathetic peaks were 4-26 s prior to the ACT and the returns to normal were 54-57 s after the ACT, which could be interpreted as the feedforward and adaptation of the autonomic regulation process in the human body, respectively. These results might be helpful for understanding the regulatory mechanisms of the autonomic system and its effects on the cardiovascular system.
... Confidence intervals of the uncorrelated indices were calculated for the five databases. Bootstrapped 1 95 % confidence intervals of the median [10][11][12] were analysed in MatLab with 10,000 replications [13]. The bias-corrected and accelerated percentile method was used as it is transform respecting and has second-order accuracy [14] making it best for dealing with skew and bias in the bootstrap sampling distribution [15,16]. ...
Article
Heart rate variability (HRV) analysis over shorter periods may be useful for monitoring dynamic changes in autonomic nervous system activity where steady-state conditions are not maintained (e.g. during drug administration, or the start or end of exercise). This study undertakes a validation of 70 HRV indices that have previously been identified as possible for short-term use. The indices were validated over 10 × 30 beat windows using PhysioNet databases with physiological states of rest, active, exercising, sleeping, and meditating (N from 12 to 20). Baseline 95 % confidence intervals of the median were established with bootstrap resampling (10,000x). Statistical significance was assessed using the overlap of 95 % confidence intervals. Thirty-one indices could differentiate between resting and at least one physiological state using 30 beat windows. All respiratory sinus arrhythmia indices and Poincaré plot indices were strongly correlated to time domain measures (SDNN or RMSSD). Spectral indices using the Lomb-Scargle algorithm were able to correctly identify paradoxical shifts in power with meditation and reduced power in exercise. Some less-known indices gave interesting results: PolVar20 identified the higher sympathetic activity of exercise with the largest positive magnitude. These indices should now be considered for rigorous gold standard tests with pharmacological blockade.
... Repeated heart rate variability (HRV) measures are performed in clinical settings to predict mortality of patients (Kleiger et al., 1987) and the general population (Kleiger et al., 1991). In addition, HRV provides an index of autonomic balance; sympathetic and parasympathetic activity (Akselrod et al., 1981) and can be used to monitor autonomic activity during exposures to different environmental conditions (Hughson et al., 1994, Westerlund et al., 2006). For these reasons, the reliability of HRV measures is important if valid conclusions are to be derived from its use. ...
... Subjects entered and stood in the first room ( À 60 AE 3 1C) for 20 s before entering the second room ( À 110 AE 3 1C) for 3 min. The duration and temperature of the cold chamber were similar to that utilized elsewhere (Westerlund et al., 2003Westerlund et al., , 2006Westerlund et al., , 2009 Klimek et al., 2010). Subjects were instructed by the trained machine operator to walk slowly around the chamber and to flex and extend their elbow and fingers throughout the 3 min. ...
Article
The purpose of this study was to investigate the effects of whole-body cryotherapy (WBC) on proprioceptive function, muscle force recovery following eccentric muscle contractions and tympanic temperature (T(TY) ). Thirty-six subjects were randomly assigned to a group receiving two 3-min treatments of -110 ± 3 °C or 15 ± 3 °C. Knee joint position sense (JPS), maximal voluntary isometric contraction (MVIC) of the knee extensors, force proprioception and T(TY) were recorded before, immediately after the exposure and again 15 min later. A convenience sample of 18 subjects also underwent an eccentric exercise protocol on their contralateral left leg 24 h before exposure. MVIC (left knee), peak power output (PPO) during a repeated sprint on a cycle ergometer and muscles soreness were measured pre-, 24, 48 and 72h post-treatment. WBC reduced T(TY) , by 0.3 °C, when compared with the control group (P<0.001). However, JPS, MVIC or force proprioception was not affected. Similarly, WBC did not effect MVIC, PPO or muscle soreness following eccentric exercise. WBC, administered 24 h after eccentric exercise, is ineffective in alleviating muscle soreness or enhancing muscle force recovery. The results of this study also indicate no increased risk of proprioceptive-related injury following WBC.
... This effect is mediated by neuronal and humoral factors (Buemi et al. 1997;Chen et al. 2008;Di Carli et al. 1997;Victor et al. 1987). Since different effects can be observed after cooling the face in the cold face test , also the localization of cooling is evidently of importance (Westerlund et al. 2006). ...
... This effect was also established during exercise in hypoxic and normoxic environments (Zupet et al. 2009), but has not been reported by all (Buchheit et al. 2004). In addition, habituation to repeated short cold-air exposures has been reported to increase high frequency activity (parasympathetic activity) (Westerlund et al. 2006). However, there are no experiments which have investigated the response of HRV to head-out, whole body immersions in cold-water, or used this technique to establish if a cross-adaptive effect occurs between repeated cold water immersions and hypoxia. ...
Article
Adaptation to an environmental stressor is usually studied in isolation, yet these stressors are often encountered in combination in the field, an example being cold and hypoxia at altitude. There has been a paucity of research in this area, although work with rodents indicates that habituation to repeated short cold exposures has a cross-adaptive effect during hypoxia. The present study tested the hypothesis that cross-adaptation is also possible with humans. Thirty-two male volunteers were exposed to 10 min bouts of normoxic and hypoxic (FIO2 0.12) rest and exercise (100 W on a recumbent cycle ergometer). These were repeated after a 96 h interval, during which participants completed six, 5 min immersions in either cold (12°C, CW) or thermoneutral water (35°C, TW). Venous blood samples were taken immediately after each bout, for determination of catecholamine concentrations. A three-lead ECG was recorded throughout and the final 5 min of each bout was analysed for heart rate variability using fast fourier transformations (and displayed as log transformed data (ln)). In comparison with the first hypoxic exercise exposure, the second exposure of the CW group resulted in an increased ln high frequency (ln HF) power (P < 0.001) and reduced adrenaline (P < 0.001) and noradrenaline concentrations (P < 0.001). Adrenaline and noradrenaline concentrations were lower in the CW group during the second hypoxic exercise compared to the TW group (P = 0.042 and P = 0.003), but ln HF was not. When separated into hypoxic sensitive and hypoxic insensitive subgroups, ln HF was higher in the hypoxic sensitive CW group during the second hypoxic exercise than in any of the other subgroups. Cold habituation reduced the sympathetic response (indicated by the reduced catecholamine concentrations) and elevated the parasympathetic activity (increased ln HF power) to hypoxic exercise. These data suggest a generic autonomic cross-adaptive effect between cold habituation and exposure to acute hypoxia in humans.
... Subjects entered the first room (-60 ± 3°C) for 20 seconds before entering the second room (-110 ± 3°C) for 3 min. The duration and temperature of the cold chamber were similar to that utilized elsewhere (7,8,16,19,20,33,42,44). To negate any potential insulating effects of stationary air, the subjects were instructed to walk slowly in a circular direction and to flex and extend their elbows and fingers. ...
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Cryotherapy is currently used in various clinical, rehabilitative, and sporting settings. However, very little is known regarding the impact of cooling on the microcirculatory response. Objectives: The present study sought to examine the influence of two commonly employed modalities of cryotherapy, whole body cryotherapy (WBC; -110°C) and cold water immersion (CWI; 8±1°C), on skin microcirculation in the mid- thigh region. Methods: The skin area examined was a 3 × 3 cm located between the most anterior aspect of the inguinal fold and the patella. Following 10 minutes of rest, 5 healthy, active males were exposed to either WBC for 3 minutes or CWI for 5 minutes in a randomised order. Volunteers lay supine for five minutes after treatment, in order to monitor the variation of red blood cell (RBC) concentration in the region of interest for a duration of 40 minutes. Microcirculation response was assessed using a non-invasive, portable instrument known as a Tissue Viability imaging system. After a minimum of seven days, the protocol was repeated. Subjective assessment of the volunteer’s thermal comfort and thermal sensation was also recorded. Results: RBC was altered following exposure to both WBC and CWI but appeared to stabilise approximately 35 minutes after treatments. Both WBC and CWI affected thermal sensation (p < 0.05); however no betweengroup differences in thermal comfort or sensation were recorded (p > 0.05). Conclusions: As both WBC and CWI altered RBC, further study is necessary to examine the mechanism for this alteration during whole body cooling.
... A WBC programme might also be considered as physical exercise programme mimetics due to the fact that it induces a pulsative expression of myokines (IL-6, irisin) [14]. Authors suggest that some of the patterns of ANS modulation due to the WBC programme are similar to the effects of physical exercise training [44]. The acute effects of both stressors, namely physical exercise and cold exposure, are related to an increase in stress hormones and sympathetic activity [45]. ...
Article
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Background The aim of this study was to explore the tolerability and effect of static stretching (SS) and whole body cryotherapy (WBC) upon fatigue, daytime sleepiness, cognitive functioning and objective and subjective autonomic nervous system functioning in those with Chronic Fatigue Syndrome (CFS) compared to a control population. Methods Thirty-two CFS and eighteen healthy controls (HC) participated in 2 weeks of a SS + WBC programme. This programme was composed of five sessions per week, 10 sessions in total. Results A significant decrease in fatigue was noted in the CFS group in response to SS + WBC. Some domains of cognitive functioning (speed of processing visual information and set-shifting) also improved in response to SS + WBC in both CFS and HC groups. Our study has confirmed that WBC is well tolerated by those with CFS and leads to symptomatic improvements associated with changes in cardiovascular and autonomic function. Conclusions Given the preliminary data showing the beneficial effect of cryotherapy, its relative ease of application, good tolerability, and proven safety, therapy with cold exposure appears to be an approach worth attention. Further studies of cryotherapy as a potential treatment in CFS is important in the light of the lack of effective therapeutic options for these common and often disabling symptoms.
... Cryotherapy as an emerging physiotherapy gradually accepted and used by more athletes and coaches, cryotherapy originate from Japan, the main application is to treat rheumatism clinical diseases (Westerlund 2009), and in the following nearly 30 years, especially in Europe and the United States and other countries began to develop rapidly (Westerlund et al. 2006;Cholewka et al. 2006;Vybiral et al. 2000;Lu et al. 2021). Application field also gradually extended from clinical medicine to sports medicine, and further application in the practice of sports training, it can be a good pain relief, speed recovery and reduce the inflammatory response after injury, so for athletes can be a good means of recovery. ...
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The purpose of this study was to investigate the influence of cryotherapy on the balance ability after lower extremity muscle fatigue. Twelve table tennis players were selected in this research. The static and dynamic balance abilities of the participants at six different moments were collected by a 1000 HZ Kistler force platform and Y balance test system. SPSS19.0 software was used to analyze the results of experimental indicators by selecting two-factor repeated measurement ANOVA. 1) From the moment of 24 h post intervention, the effect of cryotherapy on dynamic balance recovery was significantly better than no cryotherapy. 2) Except for the COP (Center of Pressure) maximum displacement on ML (Medium-Lateral axis) at the moment of 72 h post intervention, the cryotherapy had no positive effect on the recovery of static balance ability. 3) Cryotherapy has a significant negative impact on the COP maximum displacement in ML and AP (Antero-Posterior axis) at the moment of post cryotherapy, which may lead to the decline of static balance ability. It was not recommended to use cryotherapy for balance recovery if the competition was on the same day or within 24 h. However, the cryotherapy was recommended to use if the competition was in the next day or after the next day.
... Repeated heart rate variability (HRV) measures are performed in clinical settings to predict mortality of patients (Kleiger et al., 1987) and the general population (Kleiger et al., 1991). In addition, HRV provides an index of autonomic balance; sympathetic and parasympathetic activity (Akselrod et al., 1981) and can be used to monitor autonomic activity during exposures to different environmental conditions (Hughson et al., 1994, Westerlund et al., 2006. For these reasons, the reliability of HRV measures is important if valid conclusions are to be derived from its use. ...
... Direct physiological effects from the use of post-exercise cryotherapy have been reported, including substantial increases in testosterone [12], blood catecholamines (norepinephrine, epinephrine and dopamine) [13], salivary α-amylase (a biomarker of autonomic nervous system activation) [14], decreases in markers of oxidative stress (lipid peroxidation and antioxidants) [15,16] and anti-inflammatory biomarkers (e.g., IL-1β, IL-6, protein C-reactive (CRP) and tumor necrosis factor alpha (TNF-α)) [17]. WBC exposure also influences heart rate variability (HRV) measures [18] and decreased perceived muscle fatigue [3]. WBC and PBC purportedly enhances cardiovascular fitness, sleep quality, temperature regulation, and increases energy intake, appetite regulation, overall mood and well-being [19][20][21]. ...
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Whole- (WBC) and partial-body cryotherapy (PBC) are commonly used sports medicine modalities for the treatment of injury and exercise recovery. Physiological and perceptual effects have the potential to be utilised in a novel application that involves pre-exercise WBC and PBC exposure to improve physical performance. A systematic literature search of multiple databases was conducted in July 2021 to identify and evaluate the effects of pre-exercise exposure of WBC or PBC on physical performance measures, and any potential translational effects. The following inclusion criteria were applied: (1) use of WBC or PBC exposure pre-exercise, (2) use of WBC or PBC in healthy and/or athletic populations, (3) control group was used in the data collection, and (4) investigated physiological, psychosocial or direct physical performance impacts of pre-exercise cryotherapy exposure. A total of 759 titles were identified, with twelve relevant studies satisfying the inclusion criteria after full-text screening. The twelve studies were categorised into three key areas: performance testing (n = 6), oxidative stress response (n = 4) and lysosomal enzyme activity (n = 2). The potential for eliciting favourable physical and physiological responses from pre-exercise WBC or PBC is currently unclear with a paucity of good quality research available. Furthermore, a lack of standardisation of cryotherapy protocols is a current challenge.
... Discrepancies between studies may be explained by the different pre-intervention exercise type and timing, and the methodology of sleep assessment. One of the rationale for using WBC after exercise is to reduce sympathetic activity and increase vagal tone after the exposure (21,40) and during subsequent sleep (18). In the present study, we examined the sympathovagal balance during the first sequence of SWS (29) for WBC and CONT conditions. ...
Article
Introduction: This study aimed to explore the relationship between elite rugby union match and post-match sleep architecture and to investigate the effects of a high-heat capacity mattress (MAT) and a whole-body cryotherapy session (WBC) on post-match sleep architecture. Methods: Nineteen elite male U23 rugby union players performed in three official matches, followed by three experimental conditions, in a randomized order: MAT, WBC, and no intervention (CONT). Match load was evaluated using global positioning system (GPS) trackers and video analyses. Sleep architecture was assessed by polysomnography (PSG). Core body temperature (CBT) and mattress surface temperature were monitored during sleep. Linear mixed-effects models were conducted to assess the effects of each experimental condition on sleep, with match load variables as covariates. Results: A lower wake after sleep onset (β = -10.5 min, p < 0.01) and higher rapid-eye-movement sleep proportion (β = +2.8%, p < 0.05) were reported for MAT compared with CONT. Moreover, a lower mean CBT (β = -0.135°C, p < 0.001) and mean mattress surface temperature (β = -2.736°C, p < 0.001) during sleep were observed for MAT compared CONT. Whole-body cryotherapy did not affect nocturnal CBT nor interfere with sleep architecture. For every 100-m increase in high-speed running distance, a higher slow-wave sleep (SWS; β = +1.1%, p = 0.05) and lower light sleep proportion (β = -1.2%, p < 0.05) proportion were observed. Conversely, for every 10 supplementary collisions, a lower SWS (β = -1.9, p = 0.09) and higher light sleep (β = +2.9%, p < 0.001) proportion were observed. Conclusion: MAT use had a positive effect on sleep architecture after an elite rugby union match, potentially through a more efficient nocturnal heat transfer.
... Whatever the cryotherapy technique used, results showed that a single 3-min cryostimulation induced a strong autonomic response. Same results were found byWesterlund et al. (2006) on how an extreme cold air exposure influences cardiac autonomic regulation and its adaptation effects on healthy women. ...
Article
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This investigation examined the effect of partial-body cryostimulation (PBC) performed in the recovery time between a strength training and an interval running (IR). Nine rugby players [age 23.7±3.6, BMI 28.0±2.6 kg/m2] were randomly exposed to two different conditions: i) PBC: 3-min at -160°C; ii) passive recovery at 21°C. We recorded the bioelectrical impedance analysis (BIA), temperature, and cardiac autonomic variables in three moments: at baseline, after strength training (R0) and after 90-min of recovery (R90). Additionally, the blood lactate concentration was measured 1-min before and 2.5-min after the IR. The heart rate, energy cost, minute ventilation, oxygen uptake and metabolic power were assessed during the IR. The homeostatic hydration status was affected by the execution of intense strength training sub-session. Then, after PBC the BIA vector was restored back, close to normohydration status. Autonomic variables changed over time in both conditions, although the mean differences and effect sizes were higher in the PBC condition. During IR, the heart rate was 3.5% lower after PBC, and the same result was observed for the oxygen uptake (~4.9%) and ventilation (~6.5%). The energy cost measured after cryotherapy was ~9.0% lower than after passive recovery. Cryotherapy enhances recovery after a single strength training, while during the subsequent interval running it shows a reduction in cardiorespiratory and metabolic parameters. PBC may be used in those athletes who compete or train more than once in the same day to improve recovery between successive training sessions or competitions.
... They concluded that, through evidence of cold habituation occurring on both sides of the body, habituation is controlled more by central pathways as opposed to cutaneous receptors . Habituation has also been shown to attenuate responses to sudden cold water immersion, evidenced by reductions in sympathetic, tachycardia, and tachypnea responses (Kang et al., 1970;De Lorenzo et al., 1999;Vybiral et al., 2000;Huttunen et al., 2001;Westerlund et al., 2006;Barwood et al., 2007;Makinen et al., 2008;Li et al., 2009;Harper, 2012;Croft et al., 2013;Castellani and Young, 2016;Tipton, 2016). Habituation changes that lead to warmer skin, greater energy conservation, and improved comfort, with evidence suggesting that these originate more centrally than peripherally, may indeed have the ability to improve cognitive performance. ...
Article
Athletes, occupational workers, and military personnel experience cold temperatures through cold air exposure or cold water immersion, both of which impair cognitive performance. Prior work has shown that neurophysiological pathways may be sensitive to the effects of temperature acclimation and, therefore, cold acclimation may be a potential strategy to attenuate cold-induced cognitive impairments for populations that are frequently exposed to cold environments. This review provides an overview of studies that examine repeated cold stress, cold acclimation, and measurements of cognitive performance to determine whether or not cold acclimation provides beneficial protection against cold-induced cognitive performance decrements. Studies included in this review assessed cognitive measures of reaction time, attention, logical reasoning, information processing, and memory. Repeated cold stress, with or without evidence of cold acclimation, appears to offer no added benefit of improving cognitive performance. However, research in this area is greatly lacking and, therefore, it is difficult to draw any definitive conclusions regarding the use of cold acclimation to improve cognitive performance during subsequent cold exposures. Given the current state of minimal knowledge on this topic, athletes, occupational workers, and military commands looking to specifically enhance cognitive performance in cold environments would likely not be advised to spend the time and effort required to become acclimated to cold. However, as more knowledge becomes available in this area, recommendations may change.
... 11 As a result, multiple researchers have conducted studies that have adopted this vital sign as an index of psychological condition, and as a variable to interpret the user's physiological stability with much more reliability than survey questions. Liu et al. 32 demonstrated that heart rate variations are related to thermal comfort in a temperature range of 21 C-30 C, and Lan et al. 33 revealed that heart rates were lower at 22 C than at 30 C. On the other hand, Westerlund et al. 34 reported conflicting results showing that the heart rates of participants would increase significantly in a cold environment. In addition, Choi et al. 11 revealed that heart rate changes occurred primarily between different activity levels rather than in different thermal conditions. ...
Article
In the domain of building science and architectural design, the immersive virtual environment is being commonly adopted due to its convenience and cost-effectiveness, especially for research relevant to occupant behaviour in a building indoor environmental control. The goal of this study is to investigate whether such an immersive virtual environment condition could affect an occupant's thermal sensation and physiological response to ambient conditions differently, as compared to a real indoor environment, even though those two thermal conditions are the same or very similar. A series of human subject experiments using 18 participants was conducted in an environmental chamber. While thermal conditions were controlled at 20℃ to 30℃ in each environment, respectively, participants were asked to periodically report their thermal sensations on their body. Their heart rates were also continuously measured. The result of our experiments revealed that overall thermal sensations on the whole and local body areas showed some significant differences between the indoor environment and immersive virtual environment conditions during the same thermal conditions. Also, the heart rate difference between two environmental conditions was statistically significant at every thermal sensation level. These findings support the idea that significant physiological response differences could be affected by the immersive virtual environment condition.
... Larger skin folds have been shown to require longer ice exposure than smaller skin folds to elicit similar reductions in deep tissue temperature (Otte et al., 2002), and differences in the degree of skin temperature cooling experienced have been reported between high and low body mass index in individuals following WBC (Cholewka et al., 2012). Consistent with the link between body mass index and cooling, there have been a number of attempts to examine the impact of WBC on skin temperature (Cholewka et al., 2006Cholewka et al., , 2012 Klimek et al., 2011; Hammond et al., 2014) along with core temperature (Westerlund et al., 2003; Costello et al., 2012b), heart rate and blood pressure (Westerlund et al., 2004Westerlund et al., , 2006 ), but with little attention paid to sexual dimorphism, morphological and protocol differences. It is surprising that sexual dimorphism has received relatively little attention in WBC research, especially as WBC has been used in a wide variety of populations, with varying results, in both clinical and well trained individuals. ...
... Westerlund et al. (Westerlund et al., 2006) also showed an increase in parasympathetic activity in ten females who were moderately physically active after a single 2-min WBC exposure at -110°C. However, when such exposures were repeated over 3 months with 3 exposures per week, an attenuation in the increase of the parasympathetic tone was observed. ...
... WBC and acute cooling induce an increase in high frequency power and an increase in cardiac parasympathetic modulation. However, after 3 months of repeated WBC, the increase in parasympathetic tone in healthy females was limited as a result of adaptation. [22] Thus, the treatment should not be harmful to cardiac function in healthy people. A study was conducted in top-level athletes who were treated once a day for 1 week with WBC. Measurement was taken of the cardiac markers troponin I and high sensitivity C-reactive protein (hsCRP) [parameters linked to damage and necrosis of cardiac muscula ...
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Cold therapy is commonly used as a procedure to relieve pain symptoms, particularly in inflammatory diseases, injuries and overuse symptoms. A peculiar form of cold therapy (or stimulation) was proposed 30 years ago for the treatment of rheumatic diseases. The therapy, called whole-body cryotherapy (WBC), consists of exposure to very cold air that is maintained at −110°C to −140°C in special temperature-controlled cryochambers, generally for 2 minutes. WBC is used to relieve pain and inflammatory symptoms caused by numerous disorders, particularly those associated with rheumatic conditions, and is recommended for the treatment of arthritis, fibromyalgia and ankylosing spondylitis. In sports medicine, WBC has gained wider acceptance as a method to improve recovery from muscle injury. Unfortunately, there are few papers concerning the application of the treatment on athletes. The study of possible enhancement of recovery from injuries and possible modification of physiological parameters, taking into consideration the limits imposed by antidoping rules, is crucial for athletes and sports physicians for judging the real benefits and/or limits of WBC. According to the available literature, WBC is not harmful or detrimental in healthy subjects. The treatment does not enhance bone marrow production and could reduce the sport-induced haemolysis. WBC induces oxidative stress, but at a low level. Repeated treatments are apparently not able to induce cumulative effects; on the contrary, adaptive changes on antioxidant status are elicited — the adaptation is evident where WBC precedes or accompanies intense training. WBC is not characterized by modifications of immunological markers and leukocytes, and it seems to not be harmful to the immunological system. The WBC effect is probably linked to the modifications of immunological molecules having paracrine effects, and not to systemic immunological functions. In fact, there is an increase in antiinflammatory cytokine interleukin (IL)-10, and a decrease in proinflammatory cytokine IL-2 and chemokine IL-8. Moreover, the decrease in intercellular adhesion molecule-1 supported the anti-inflammatory response. Lysosomal membranes are stabilized by WBC, reducing potential negative effects on proteins of lysosomal enzymes. The cold stimulation shows positive effects on the muscular enzymes creatine kinase and lactate dehydrogenase, and it should be considered a procedure that facilitates athletes’ recovery. Cardiac markers troponin I and high-sensitivity C-reactive protein, parameters linked to damage and necrosis of cardiac muscular tissue, but also to tissue repair, were unchanged, demonstrating that there was no damage, even minimal, in the heart during the treatment. N-Terminal pro B-type natriuretic peptide (NT-proBNP), a parameter linked to heart failure and ventricular power decrease, showed an increase, due to cold stress. However, the NT-proBNP concentrations observed after WBC were lower than those measured after a heavy training session, suggesting that the treatment limits the increase of the parameter that is typical of physical exercise. WBC did not stimulate the pituitary-adrenal cortex axis: the hormonal modifications are linked mainly to the body’s adaptation to the stress, shown by an increase of noradrenaline (norepinephrine). We conclude that WBC is not harmful and does not induce general or specific negative effects in athletes. The treatment does not induce modifications of biochemical and haematological parameters, which could be suspected in athletes who may be cheating. The published data are generally not controversial, but further studies are necessary to confirm the present observations.
Article
The purpose of this study was to investigate the effects of whole-body cryotherapy (WBC) on proprioceptive function, muscle force recovery following eccentric muscle contractions and tympanic temperature (T TY). Thirty-six subjects were randomly assigned to a group receiving two 3-min treatments of À 110 AE 3 1C or 15 AE 3 1C. Knee joint position sense (JPS), maximal voluntary isometric contraction (MVIC) of the knee extensors, force proprioception and T TY were recorded before, immediately after the exposure and again 15 min later. A convenience sample of 18 subjects also underwent an eccentric exercise protocol on their contralateral left leg 24 h before exposure. MVIC (left knee), peak power output (PPO) during a repeated sprint on a cycle ergometer and muscles soreness were measured pre-, 24, 48 and 72 h post-treatment. WBC reduced T TY , by 0.3 1C, when compared with the control group (Po0.001). However, JPS, MVIC or force proprioception was not affected. Similarly, WBC did not effect MVIC, PPO or muscle soreness following eccentric exercise. WBC, administered 24 h after eccentric exercise, is ineffective in alleviating muscle soreness or enhancing muscle force recovery. The results of this study also indicate no increased risk of proprioceptive-related injury following WBC.
Article
The aim of the study was to follow muscular tissue electric activity after the application of whole-body cool therapy by means of surface EMG. The attention was devoted to the detection of MVC (maximum intentional contraction) before and after entering the cold chamber. Moreover, the authors followed the beginning of muscular fatigue in the course of isometric contraction before and after the application of whole-body cold therapy (CChT). Muscular activity was recorded from brachial m. biceps. Five top sportsmen at the age of 20-35 years participated in the measurement. Results of the study revealed that surface electromyography can detect changes in electric activity after the application of wehole-body cool therapy. In four of the five measured probands there was a delayed beginning of muscular fatigue after the application of CChT. Moreover, the application of CChT resulted in increased MVC in all five measured probands.
Article
Literature data on specific influence of general air cryogenic effects on homeostasis parameters have been presented. Cold trainings raise general nonspecific resistance of a human body. Character of response adaptive shifts depends on initial functional state, including the psychoemotional sphere and the mode of cryogenic sessions. According to the literature data of Russian and European authors, extreme cryotherapy is a universal and effective technique of primary and secondary prevention of a wide range of diseases.
Article
Cryotherapy is commonly used as a procedure to relieve pain symptoms, particularly in inflammatory diseases, injuries and overuse symptoms. A peculiar form of cold therapy or stimulation was proposed 30 years ago for the treatment of rheumatic diseases. The therapy consists in the exposure to very cold air in special cryochambers. The air is maintained at temperatures between -110 and -160°C. The treatment was named whole-body cryotherapy (WBC). It consists in a brief exposure to extreme cold in a temperature-controlled chamber. It is applied to relieve pain and inflammatory symptoms caused by numerous disorders, particularly those associated with rheumatic conditions, and it is recommended for the treatment of arthritis, fibromyalgia and ankylosing spondylitis. The aim of this study was to investigate the effects of different treatment of WBC on blood pressure (BP) and heart rate (HR) parameters in adult subjects characterized from non-pathological values of BP. Eighty subjects (36 females, 44 males, age range 19-80 years) submitted to 4-17 WBC applications for a total of 816 treatments were recruited. Immediately before and after each WBC application systolic and diastolic BP and HR were measured and recorded. We did not find significant differences in BP and HR (p > 0.05). WBC seems to be safe with respect to unwanted BP and HR alterations for adult patients. An individual monitoring of subjects is recommended over the treatment, but pathological changes of circulatory parameters can be considered rare and occasional.
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We assessed the effects of a 3-min partial-body cryostimulation (PBC) exposure-where the whole body is exposed to extreme cold, except the head-on cognitive inhibition performance and the possible implications of parasympathetic cardiac control and cerebral oxygenation. In a randomized controlled counterbalanced cross-over design, eighteen healthy young adults (nine males and nine females) completed a cognitive Stroop task before and after one single session of PBC (3-min exposure at − 150 °C cold air) and a control condition (3 min at room temperature, 20 °C). During the cognitive task, heart rate variability (HRV) and cerebral oxygenation of the prefrontal cortex were measured using heart rate monitoring and near-infrared spectroscopy methods. We also recorded the cerebral oxygenation during the PBC session. Stroop performance after PBC exposure was enhanced (562.0 ± 40.2 ms) compared to pre-PBC (602.0 ± 56.4 ms; P < 0.042) in males only, accompanied by an increase (P < 0.05) in HRV indices of parasympathetic tone, in greater proportion in males compared to females. During PBC, cerebral oxygenation decreased in a similar proportion in males and females but the cerebral extraction (deoxyhemoglobin: ΔHHb) remained higher after exposure in males, only. These data demonstrate that a single PBC session enhances the cognitive inhibition performance on a Stroop task in males, partly mediated by a greater parasympathetic cardiac control and greater cerebral oxygenation. The effects of PBC on cognitive function seem different in females, possibly explained by a different sensitivity to cold stimulation.
Article
Whole body cryotherapy (WBC) in a cryo-chamber as a medical treatment was first established in Japan in the 1980s, later in Central Europe, and is now becoming more popular also in the United States. The exposure to extreme, non-physiological environmental conditions in a cryo-chamber at −110 °C may exceed the normal adaption capacity. The aim of this study was to investigate the effects of WBC on blood pressure (BP) readings in adult subjects with rheumatic disorders and normal or moderately elevated BP. A sample of 23 subjects (8 female, 15 male) which were recruited according to their pathology between the age of 35 and 69 years undergoing 21 WBC applications was divided into three groups: a group of subjects with anti-hypertensive therapy, a group of subjects with mild arterial hypertension without medical treatment, and a normotensive control-group. A total of 483 BP readings were taken immediately before and after each WBC application. The systolic and diastolic BP were recorded, and the mean arterial pressure, and the amplitude of BP were calculated. A statistically significant rise of BP after WBC was found in the whole sample and in the normotensive group. Over the course of time, no significant change of BP behavior was observed, except for normotensive subjects, who showed a wider range in their systolic BP values. Generally accepted exclusion criteria were applied, and in our sample group WBC was safe with respect to unwanted BP alterations for adult subjects under 70 years—regardless of a pre-existing untreated mild or pharmacologically treated arterial hypertension. Greater changes of BP values might infrequently occur, so an individual monitoring of subjects is necessary.
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In 57 normal subjects (age 20-60 years), we analyzed the spontaneous beat-to-beat oscillation in R-R interval during control recumbent position, 90° upright tilt, controlled respiration (n = 16) and acute (n = 10) and chronic (n = 12) β-adrenergic receptor blockade. Automatic computer analysis provided the autoregressive power spectral density, as well as the number and relative power of the individual components. The power spectral density of R-R interval variability contained two major components in power, a high frequency at ~ 0.25 Hz and a low frequency at ~ 0.1 Hz, with a normalized low frequency: high frequency ratio of 3.6 ± 0.7. With tilt, the low-frequency component became largely predominant (90 ± 1%) with a low frequency: high frequency ratio of 21 ± 4. Acute β-adrenergic receptor blockade (0.2 mg/kg IV propranolol) increased variance at rest and markedly blunted the increase in low frequency and low frequency: high frequency ratio induced by tilt. Chronic β-adrenergic receptor blockade (0.6 mg/kg p.o. propranolol, t.i.d.), in addition, reduced low frequency and increased high frequency at rest, while limiting the low frequency: high frequency ratio increase produced by tilt. Controlled respiration produced at rest a marked increase in the high-frequency component, with a reduction of the low-frequency component and of the low frequency: high frequency ratio (0.7 ± 0.1); during tilt, the increase in the low frequency: high frequency ratio (8.3 ± 1.6) was significantly smaller. In seven additional subjects in whom direct high-fidelity arterial pressure was recorded, simultaneous R-R interval and arterial pressure variabilities were examined at rest and during tilt. Also, the power spectral density of arterial pressure variability contained two major components, with a relative low frequency: high frequency ratio at rest of 2.8 ± 0.7, which became 17 ± 5 with tilt. These power spectral density components were numerically similar to those observed in R-R variability. Thus, invasive and noninvasive studies provided similar results. More direct information on the role of cardiac sympathetic nerves on R-R and arterial pressure variabilities was derived from a group of experiments in conscious dogs before and after bilateral stellectomy. Under control conditions, high frequency was predominant and low frequency was very small or absent, owing to a predominant vagal tone. During a 9% decrease in arterial pressure obtained with IV nitroglycerin, there was a marked increase in low frequency, as a result of reflex sympathetic activation. Bilateral stellectomy prevented this low-frequency increase in R-R but not in arterial pressure autospectra, indicating that sympathetic nerves to the heart are instrumental in the genesis of low-frequency oscillations in R-R interval.
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The blood pressure responses to an acute and long-term (three months) whole-body cryotherapy (WBC) were measured in men and women. Acute cold exposure (−10°C, −60°C, −110°C) increased both systolic and diastolic blood pressures temporarily. Neither significant gender differences nor adaptation in blood pressures were found during WBC. The variation of individual responses to the acute and long-term WBC was wide.
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In a cross-over study, the short-term efficacy of whole-body cold therapy and hot mud packs in patients with generalized tendomyopathy (fibromyalgia) was compared. As a pain assessment, visual analog scale and so-called pain score were measured; dolorimetry of the 24 tender points and eight control points was performed as well. Using these methods, we found that there is a significant improvement of all parameters examined during a 2-h period of measurements after cold application, and a marked improvement was also detectable 24 h after this therapy. In contrast, only pain score values showed a slight decrease immediately after hot mud-pack therapy, and no significant differences were found in visual analog scale and pressure tenderness as measured dolorimetrically. Central inhibition of nociceptors as a result of an activation of A-delta system as well as a blockade of gamma-motoneurons are discussed to be a mechanism of action of whole-body cold therapy, resulting in a decrease in muscle tonus. Long-term studies are needed to determine, if there is any enduring effect of whole-body cold therapy on pain in the patients with generalized tendomyopathy.
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The purpose of this study was to determine whether or not repeated short-term cold water immersions can induce a change in the activity of the sympathetic nervous system and, consequently, in cardiovascular functions in healthy young athletes. Changes in some plasma hormone concentrations were also followed. A single cold water immersion (head-out, at 14 degrees C, for 1 h) increased sympathetic nervous system activity, as evidenced by a four-fold increase (P < 0.05) in plasma noradrenaline concentration. Plasma adrenaline and dopamine concentrations were not increased significantly. Plasma renin-angiotensin activity was reduced by half (P < 0.05) during immersion but plasma aldosterone concentration was unchanged. Stimulation of the sympathetic nervous system during immersion did not induce significant changes in heart rate, but induced peripheral vasoconstriction (as judged from a decrease in skin temperature) and a small increase (by 10%) in systolic and diastolic blood pressures. No clear change in reactivity of the sympathetic nervous system was observed due to repeated cold water immersions (three times a week, for 6 weeks). Neither the plasma renin-angiotensin activity, aldosterone concentration nor cardiovascular parameters were significantly influenced by repeated cold water immersions. A lowered diastolic pressure and an increase in peripheral vasoconstriction were observed after cold acclimation, however. Evidently, the repeated cold stimuli were not sufficient to induce significant adaptational changes in sympathetic activity and hormone production.
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Harmful cardiac events occurs frequently after exercise. However, the cardiac autonomic regulation after vigorous exercise is not well known. This study was designed to assess heart rate (HR) variability before and after a 75 km cross-country skiing race. HR variability was assessed by using standard statistical measures along with spectral and quantitative Poincarè plot analysis of HR variability in 10 healthy male subjects (age 36 +/- 11 years). The average HR was at the same level 1 day after the race as before the race, but on the second day, HR was significantly lower (P<0.001) compared with the prerace and 1 day after values. The normalized high-frequency (HF) spectral component of HR variability (nuHF) was lower (P<0.01) on the first day after the maximal exercise compared with the pre-exercise values but returned to or even exceeded the prerace level on the second day (P<0.01). The changes in short-term R-R interval variability analysed from the Poincaré plot were similar to those observed in the HF spectral component. The normalized low-frequency (LF) spectral component of HR variability (nuLF) was higher (P<0.01) on the first day after the exercise compared with the prerace levels and it also returned to the pre-exercise level or even dropped below it on the second day after the race. The mean time it took the HF spectral component to return to the pre-exercise level was 4.2 +/- 4.2 h (ranging from 0 to 12 h). This recovery time correlated inversely with the maximal oxygen consumption (VO2max) measured during the bicycle exercise test before the skiing race (r=-0.712, P<0.016). The cardiac vagal outflow is blunted for several hours after prolonged vigorous exercise. The recovery time of reduced vagal outflow depends on individual cardiorespiratory fitness and there is an accentuated rebound of altered autonomic regulation on the second day after prolonged exercise.
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This study was designed to assess the effects of moderate- and high-volume aerobic training on the time domain and on spectral and fractal heart rate (HR) variability indexes. Sedentary subjects were randomized into groups with moderate-volume training (n = 20), high-volume training (n = 20), and controls (n = 15). The training period was 8 wk, including 6 sessions/wk at an intensity of 70-80% of the maximum HR, lasting for 30 min/session in the moderate-volume group and 60 min/session in the high-volume group. Time domain, frequency domain, and short-term fractal scaling measures of HR variability were analyzed over a 24-h period. Mean HR decreased from 70 +/- 7 to 64 +/- 8 beats/min and from 67 +/- 5 to 60 +/- 6 beats/min (P < 0.001 for both) for the moderate- and high-volume training groups, respectively. The normalized high-frequency spectral component increased in both groups (P < 0.05). The normalized low-frequency component decreased significantly (P < 0.05), resulting in a marked decrease in low frequency-to-high frequency ratio in both groups. In addition, short-term scaling exponent decreased in both groups (P < 0.001). There were no significant differences in the changes of HR variability indexes between groups. Aerobic training in sedentary subjects results in altered autonomic regulation of HR toward vagal dominance. A moderate training volume is a sufficient intervention to induce these beneficial effects.
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To investigate the first-ever incidence of acute myocardial infarction and stroke in a community based RA cohort compared with the general population. The RA cohort consisted of all patients in a local RA register in Malmö, Sweden (n = 1022). The patients were recruited from private and hospital based rheumatology practices, and made up the absolute majority of patients with RA in the city. The general population of Malmö, aged 16 and above, served as controls. From the Swedish National Hospital Discharge Register and the national Swedish Causes of Death Register, information about all first-ever myocardial infarctions and strokes in Malmö residents between July 1997 and December 1999 was retrieved. The age and sex adjusted standardised morbidity ratio (SMR) of the two cohorts was calculated. Fifty four patients with RA had first-ever myocardial infarctions or stroke during the study period, compared with 3862 subjects in the general population. The age and sex adjusted SMR was 161 (95% confidence interval (CI) 121 to 210). The first-ever incidence of cardiovascular disease was increased among female and male patients when studied separately. The increase of cardiovascular events in the RA cohort was mainly due to an excess of myocardial infarctions (n = 36; SMR = 176 (95% CI 123 to 244). Patients with RA in Malmö had an increased first-ever incidence of myocardial infarction or stroke compared with the general population. This confirms that cardiovascular comorbidity is of major importance in RA.
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Whole-body cryotherapy (WBC; -110 degrees C) and winter swimming (WS) in ice-cold water are severe ambient cold exposures, which are voluntarily practiced by humans in minimal clothing. The purpose was to examine thermal sensation and thermal comfort associated with WBC and WS. Twenty women similar in body mass index, age, physical activity, and use of hormonal contraception were pairwise randomized either to the WBC group or the WS group. The duration of each WBC exposure was 2 min, which was repeated three times per week for 3 months (13 weeks). Similar exposure frequency was used for the WS group, but each exposure lasted 20 s in outdoor conditions. Thermal sensation and comfort were asked with standard scales. After WBC, 65% of the thermal sensation votes were 'neutral' or 'slightly cool.' After WS, 81% of the thermal sensation votes were 'warm,' 'neutral,' or 'slightly cool.' Majority of comfort votes immediately after exposures in WBC group (98%) and in the WS group (93%) were 'comfortable' or 'slightly uncomfortable.' Thermal sensation and comfort became habituated in both groups at an early stage of trials, but the changes were less conclusive in WS group due to variable conditions outdoors. In the WBC group, cold sensation was less intense already after the second exposure. In conclusion, repeated exposures to WBC and WS in healthy women were mostly well tolerated and comfortable. The results indicate that during repeated severe whole-body cold stress of short duration, thermal sensation and comfort become habituated during the first exposures.
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Spectral analysis of spontaneous heart rate fluctuations were assessed by use of autonomic blocking agents and changes in posture. Low-frequency fluctuations (below 0.12 Hz) in the supine position are mediated entirely by the parasympathetic nervous system. On standing, the low-frequency fluctuations increase and are jointly mediated by the sympathetic and parasympathetic nervous systems. High-frequency fluctuations, at the respiratory frequency, are decreased by standing and are mediated solely by the parasympathetic system. Heart rate spectral analysis is a powerful noninvasive tool for quantifying autonomic nervous system activity.
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In a cold air chamber with pre- and main chamber patients are treated in bathing suits with covered ears, hands, feet and an operation mask for 1/2 min up to 3 min at -110°C. Therapeutic effects are lowering of pain, improvement of joint function, as well as improvement of well being. Heartbeat and blood pressure will be influenced only very little in persons with normal RR. Admittance to the cold air chamber is possible when hypertension is well under control. Bronchospasm will decrease. Stenocardia was not observed. The cold air chamber treatment does not provoke stress. Neither ACTH nor cortisone or adrenalin increase after treatment. They rather decrease. The noradrenalin level is on the other hand increasing in serum. In rheumatoid arthritis T-helper lymphocytes decrease over more than 3 hours, while T-suppressor lymphocytes increase during that period. Indications for the whole body cryotherapy are chronic joint inflammation and chronic inflammation of the cervical spine, fibrositis and fibromyositis, connective tissue diseases and autoimmune diseases.
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Local peripheral cooling (immerson of legs up to the knees into 12°C water) increased heart rate and blood pressure by 10–20% within the first 3–10min of cooling. During further cooling heart rate remained elevated, while systolic and diastolic blood pressures decreased to the control value. Data on heart rate indicate a permanent activation of the sympathetic nervous system during local cooling.Skin temperatures (measured topically by thermosensors) decreased on some non-cooled areas of the body (fingers, palms and thighs) immediately after the start of local cooling. On the other hand, skin temperatures on chest and forehead were not influenced. During cooling skin temperatures on thighs remained low, but skin temperatures on fingers tended to increase. Changes in skin temperatures on non-cooled areas of the body indicate that a permanent and generalized activation of the sympathetic nervous system occurs during local cooling.Cold induced cycles of vasodilation (CIVD) were observed on fingers, palms and forearms during local cooling. Minute cycles in skin temperatures were observed on forehead, thighs and chest. Minute cycles coincided with those in the heart rate, indicating a permanent, generalized but discontinuous control of vasomotion by the sympathetic nervous system during local cooling.Infrared thermographic recordings from different body areas indicated that local peripheral cooling lowered skin temperatures in all areas of the body within 5min. Distant areas of the body (extremities) and pectoral muscles showed greater hypothermia than abdominal areas and head. After 10min of cooling average skin temperatures in all areas of the body returned to the original level and further fluctuated at approximately 10–15min intervals.Data indicate that during local cooling skin blood flow in all areas of the body surface permanently fluctuates forming a mosaic of dynamic changes in skin temperatures. Since tympanic temperature increases, while skin temperature decreases immediately after the start of the local cooling, it appears that the initial vasoconstrictor response is being controlled independently of the central temperature input.
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The autonomic pathways mediating the bradycardia response to facial immersion (FI) have not been fully elaborated in man. By means of parasympathetic and sympathetic blockade we studied the heart rate response to FI in nine highly trained young swimmers, at rest and during dynamic cycle exercise. With no blockade, heart rate at rest declined with FI 36 +/- 18%. Under beta-blockade with propranolol or alpha-blockade with phentolamine FI produced a similar decrement. Atropine reduced the response. During exercise FI produced 48 +/- 9% decline without blockade. The response was similar with beta-blockade, but was completely abolished with atropine. Systolic blood pressure responses to FI measured by cuff in three subjects were small and bore no relation to the heart rate response. The results are compatible with parasympathetic efferent mediation of the heart rate response to FI. They are incompatible with a role for sympathetic mediation except as a complex interaction between parasympathetic and sympathetic influences. Hypertension and other sympathetic responses to FI do not play a role in production of bradycardia, but are apparently incidental effects. The heart rate decrement produced by FI increases with greater steady-state heart rate.
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The responses to cold hand test (blood pressure increase and tachycardia) and to a cold face test (blood pressure increase and bradycardia) were used to study the role of the autonomic nevrous system in cold adaptation in humans. The Eskimos (men, women, children) were shown to have a very weak sympathetic response to cold but the vagal response (bradycardia) was identical to that of white people. A group of mailmen from Quebec city living outdoors approximately 30 h/wk throughout the year was also studied. A significant decline in the cold pressor response and an enhanced bradycardia (cold face test) were observed at the end of the winter. Similarly the fall in skin temperature of the cheek was not as pronounced when the measurements were made in May compared to those made in October. A group of soldiers was also studied before and after an Arctic expedition. It was found that the bradycardia of the cold face test was also more pronounced after sojourning in the cold. These results indicate that repeated exposures to severe cold in men activate some adaptive mechanisms characterized by a diminution of the sympathetic response and a concomitant enhancement of the vagal activation normally observed when the extremities and the face are exposed to cold.
Article
Skin temperature measurements of the face have shown that the cheek cools faster than the nose and the nose faster than the forehead. The cooling effect of wind is maximum at wind speeds between 4.5 and 6.7 m/s. Cold winds produce significant bradycardia, which is, however, much more pronounced during the expiratory phase of respiration. A significant correlation was noted between cooling of face and the reflex bradycardia observed. Similarly, a very significant correlation was noted between drop in skin temperature and subjective evaluation of cold discomfort. Consequently, the drop in skin temperature, reflex bradycardia, and subjective evaluation are parameters which are directly affected by cold wind and can be used as adequate indicators of the degree of discomfort. When comparing the present results with the windchill index, it was found that in the zone described as "dangerously cold" the index fits well with the physiological measurements. In the zone described as "bitterly cold," the index by comparison with actual skin temperature measurements and subjective evaluation underestimates the cooling effects of combined temperature and wind by approximately 10 degrees C.
Article
Short-term oscillation of heart rate and blood pressure are mainly regulated by the automatic nervous system. It has been proposed that non-neural factors, such as changes in intrathoracic pressure, can strongly modulate this rhythmicity. Our aim was to evaluate the effect of changing intrathoracic pressure and central autonomic nervous activity on heart rate and blood pressure variability. Evaluation was performed by using spectral analysis techniques with autoregressive modelling. The variability in heart rate and blood pressure remained in animals with open chest or paralysed respiratory muscles. After vagotomy, the variability in heart rate decreased, but not that of blood pressure. Total spinal anaesthesia elicited a decrease in the variability in blood pressure. The pharmacological blockade of alpha- and beta-receptors further decreased both variabilities. It was concluded that in anaesthetized dogs heart rate and blood pressure variability are mainly of central origin and non-neural factors have only minor effect on these central rhythms. High (> 0.15 Hz), medium (0.07-0.15 Hz) and, obviously low (0.00-0.07 Hz) frequency variations in heart rate are mostly mediated vagally. In blood pressure, medium and obviously low frequency variations are modulated by sympathetic nervous system, whereas high frequency variations are secondary to the heart rate variation.
Article
1. Cold stimulus applied to the face causes bradycardia and peripheral vasoconstriction (i.e. the diving reflex), and has been suggested as a test of the autonomic pathways involved. The purpose of this study was to define standard procedures for conducting the test and analysing the responses to the cold face test, to evaluate variability in responses between subjects and within subjects when the same test is repeated, and to examine its usefulness in clinical autonomic assessment. 2. Sixteen (nine female, seven male) healthy adult (21–35 years old) subjects were used. Cold stimulus was applied with gel-filled compresses. Forehead temperature under the compress as an indication of stimulus magnitude, heap rate, blood flow in the finger, toe and calf by venous occlusion plethysmography, and systolic and diastolic blood pressure were monitored. Three protocols were carried out in which the temperature (0, 5, 10, 15°C), placement (whole face, unilateral, forehead) and duration (20, 40, 60, 120 s) of the cold compress application were varied. 3. The data indicate that 0°C compresses applied bilaterally for 40 s produced the maximum bradycardia and peripheral vasoconstriction. No subject found this test to be obnoxious, but a 120 s application was objectionable to some subjects. This cold face test resulted in 22%, 72%, 59% and 44% reductions in heart rate and blood flow to the finger, toe and calf, respectively. There was significant between-subject variability, but good consistency in responses to tests repeated in the same subject on different days, at different times of day and in different seasons. 4. Two advantages of the cold face test are: (a) it can assess sympathetic-vascular smooth muscle pathways as well as the cardiac-vagal pathway; and (b) because its afferents are independent of the stretch and pressure receptors that are stimulated in other vagal–cardiac tests (Valsalva manoeuvre and respiratory sinus arrhythmia), it can help differentiate between abnormal vagal–cardiac and abnormal transducer–afferent pathway function.
Article
Fluctuations in heart rate above 0.03 Hz reflect autonomic modulation of sinoatrial node activity. To assess the dynamics of autonomic nervous activity during and immediately after exercise, we determined the power spectrum of heart rate and respiratory fluctuations in 43 normal subjects without known cardiac disease, 8 patients with severe congestive heart failure, and 6 patients status-post cardiac transplantation before, during, and after graded-work load exercise on a cycle ergometer. Before exercise, heart rate fluctuations (spectral power) at both high (0.15-0.80 Hz) and low (0.03-0.15 Hz) frequencies were significantly higher in normal subjects than in either heart failure or transplant patients but were not different between the two groups with heart disease. During exercise, heart rate power at all frequencies rapidly and progressively decreased in normal subjects, until at peak exercise it was not different from the other two groups. During recovery, heart rate power increased in normal subjects but remained significantly below base line. The findings demonstrate a marked reduction of autonomic modulation of heart rate in patients with heart failure and after cardiac transplant and support a progressive withdrawal of vagal activity during exercise with a gradual increase during recovery in normal subjects.
Article
In 57 normal subjects (age 20-60 years), we analyzed the spontaneous beat-to-beat oscillation in R-R interval during control recumbent position, 90 degrees upright tilt, controlled respiration (n = 16) and acute (n = 10) and chronic (n = 12) beta-adrenergic receptor blockade. Automatic computer analysis provided the autoregressive power spectral density, as well as the number and relative power of the individual components. The power spectral density of R-R interval variability contained two major components in power, a high frequency at approximately 0.25 Hz and a low frequency at approximately 0.1 Hz, with a normalized low frequency:high frequency ratio of 3.6 +/- 0.7. With tilt, the low-frequency component became largely predominant (90 +/- 1%) with a low frequency:high frequency ratio of 21 +/- 4. Acute beta-adrenergic receptor blockade (0.2 mg/kg IV propranolol) increased variance at rest and markedly blunted the increase in low frequency and low frequency:high frequency ratio induced by tilt. Chronic beta-adrenergic receptor blockade (0.6 mg/kg p.o. propranolol, t.i.d.), in addition, reduced low frequency and increased high frequency at rest, while limiting the low frequency:high frequency ratio increase produced by tilt. Controlled respiration produced at rest a marked increase in the high-frequency component, with a reduction of the low-frequency component and of the low frequency:high frequency ratio (0.7 +/- 0.1); during tilt, the increase in the low frequency:high frequency ratio (8.3 +/- 1.6) was significantly smaller. In seven additional subjects in whom direct high-fidelity arterial pressure was recorded, simultaneous R-R interval and arterial pressure variabilities were examined at rest and during tilt. Also, the power spectral density of arterial pressure variability contained two major components, with a relative low frequency:high frequency ratio at rest of 2.8 +/- 0.7, which became 17 +/- 5 with tilt. These power spectral density components were numerically similar to those observed in R-R variability. Thus, invasive and noninvasive studies provided similar results. More direct information on the role of cardiac sympathetic nerves on R-R and arterial pressure variabilities was derived from a group of experiments in conscious dogs before and after bilateral stellectomy. Under control conditions, high frequency was predominant and low frequency was very small or absent, owing to a predominant vagal tone. During a 9% decrease in arterial pressure obtained with IV nitroglycerin, there was a marked increase in low frequency, as a result of reflex sympathetic activation.(ABSTRACT TRUNCATED AT 400 WORDS)
Article
Spectral analysis of spontaneous heart rate fluctuations were assessed by use of autonomic blocking agents and changes in posture. Low-frequency fluctuations (below 0.12 Hz) in the supine position are mediated entirely by the parasympathetic nervous system. On standing, the low-frequency fluctuations increase and are jointly mediated by the sympathetic and parasympathetic nervous systems. High-frequency fluctuations, at the respiratory frequency, are decreased by standing and are mediated solely by the parasympathetic system. Heart rate spectral analysis is a powerful noninvasive tool for quantifying autonomic nervous system activity.
Article
We investigated the hypothesis that beat-to-beat variability in hemodynamic parameters reflects the dynamic interplay between ongoing perturbations to circulatory function and the compensatory response of short-term cardiovascular control systems. Spontaneous fluctuations in heart rate (HR), arterial blood pressure, and respiration were analyzed by spectral analysis in the 0.02- to 1-Hz frequency range. A simple closed-loop model of short-term cardiovascular control was proposed and evaluated in a series of experiments: pharmacological blockades of the parasympathetic, alpha-sympathetic, beta-sympathetic, and renin-angiotensin systems were used to open the principal control loops in order to examine changes in the spectral pattern of the fluctuations. Atrial pacing was used to examine blood pressure variability in the absence of HR variability. We found that respiratory frequency fluctuations in HR are parasympathetically mediated and that blood pressure fluctuations at this frequency result almost entirely from the direct effect of centrally mediated HR fluctuations. The sympathetic nervous system appears to be too sluggish to mediate respiratory frequency variations. Low-frequency (0.02-0.09 Hz) fluctuations in HR are jointly mediated by the parasympathetic and beta-sympathetic systems and appear to compensate for blood pressure fluctuations at this frequency. Low-frequency blood pressure fluctuations are probably due to variability in vasomotor activity which is normally damped by renin-angiotensin system activity. Blockade of the alpha-adrenergic system, however, does not significantly alter low-frequency blood pressure fluctuations.
Article
This study investigated the fluctuations of autonomic nervous activities during the menstrual cycle. Twenty college females were tested for cardiovascular reactivity to mental challenge during both follicular and luteal phases across two menstrual cycles. Power spectral analysis of heart rate variability (HRV) was used to examine the autonomic nervous activities. At baseline, although heart rate and blood pressure did not differ across the menstrual cycle, the low-frequency (LF) component in the HRV was higher and the high-frequency (HF) component in the HRV was lower during the luteal phase than during the follicular phase. The LF/HF ratio was also significantly greater in the luteal phase. These data suggest that sympathetic nervous activities are predominant in the luteal phase as compared with follicular phase. In addition, the power spectral analysis of HRV has more sensitivity than heart rate or blood pressure in assessing the slight fluctuations of autonomic nervous activities during the menstrual cycle.
Article
During stress, low-frequency (0.01-0.15 Hz) heart rate power and plasma catecholamine levels increase in response to increased sympathetic efferent activity. To test the hypothesis that low-frequency heart rate power, a measure of sympathetic control of heart rate, directly correlates with plasma catecholamine concentrations during periods of increased sympathetic tone, we compared heart rate power spectral measures with antecubital vein norepinephrine, epinephrine, and dopamine concentrations during postural change and after cold pressor testing. We analyzed absolute levels and changes in mean heart rate, respiratory rate, blood pressure, heart rate power spectra, and concentration of norepinephrine, epinephrine, and dopamine in 14 healthy volunteers (seven female/seven male) after postural change and in six (three female/three male) during cold pressor testing. Postural change from supine to standing position resulted in increased heart rate [61 +/- 8 versus 83 +/- 11 (SD) bpm, p < 0.05], diastolic (68 +/- 7 versus 77 +/- 6 mm Hg, p < 0.05) and mean blood pressures (84 +/- 6 versus 91 +/- 9 mm Hg, p < 0.05), norepinephrine concentration (2.09 +/- 1.11 versus 3.23 +/- 1.62 nmol/L, p < 0.05), and low-frequency heart rate power (7.55 +/- 5.63 versus 33.79 +/- 23.55 bpm2, p < 0.05). High-frequency heart rate power, a measure of parasympathetic control of heart rate, decreased with standing (5.38 +/- 4.22 versus 2.94 +/- 2.69 bpm2, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Article
Spectral analysis of heart period variability was used to examine autonomic cardiac control in several tasks used in experimental and clinical assessments of autonomic nervous system function. Cardiovascular measures were recorded in healthy humans during quiet rest, reaction time shock-avoidance, cold face stress, and combined shock-avoidance/cold face stress. Shock-avoidance was characterized by sympathetic beta-adrenergic dominance, as evidenced by (1) shorter heart periods, (2) less high-frequency spectral power, (3) elevated low-frequency power, (4) increased ratios of low- to high-frequency power, and (5) a steep regression line fitted to the log-log plot of the power spectra. Cold face stress yielded (1) longer heart periods, (2) more high-frequency power, (3) decreased low-frequency spectral power, and (4) a flat regression slope, indicating vagal dominance. Quiet rest appeared as mildly vagal, with less total spectral power, and the combination task elicited a mixed vagal-sympathetic pattern. These results are discussed in the context of (1) the autonomic underpinnings of low-frequency power, (2) the autonomic effects of facial cooling, and (3) the utility of spectral analysis of heart period variability during autonomic challenge tasks for basic research and clinical application.
Article
We examined how the time and frequency domain measures of heart rate and blood pressure variability at supine rest reflect the sympathovagal balance of 23 female and male endurance athletes. Pharmacological blocking by atropine and propranolol was used as a standard for defining autonomic control of the heart. The Rosenblueth and Simeone model for neural control of heart rate was used to calculate the sympathovagal balance index (Abal). Atropinization significantly decreased all time and frequency domain measures of heart rate and blood pressure variability. beta-Blockade significantly decreased further the low- (< 0.07 Hz) and medium-frequency power (0.07-0.15 Hz) variability of R-R intervals (RRI) and SD of RRI. Abal was 0.629 +/- 0.019, indicating that parasympathetic activity predominated in the athletes. Basal heart rate (r = 0.519, P < 0.01), SD of RRI (r = -0.533, P < 0.01), root-mean-square of successive RRIs (RRI RMSSD) (r = -0.579, P < 0.05), RRI total (r = -0.557, P < 0.01) and RRI high-frequency (HF) power (r = -0.582, P < 0.01) correlated significantly with Abal and parasympathetic activity index. We concluded that the best non-invasive method of evaluating the sympathovagal balance of athletes at supine rest is to measure SD of RRI, RRI RMSSD, HF and total power of RRI variability. All heart rate variability measures were mainly parasympathetically modulated. The nature of blood pressure variability measures remained unclear and they could not be used to evaluate the sympathovagal balance among athletes.
Article
Reduced heart rate variability is associated with an unfavourable prognosis in patients with ischaemic heart disease. Whether physical training can modify this risk factor is not definitely proven. Our hypothesis was that training might increase both physical capacity and heart rate variability in elderly patients recovering from an acute coronary event, i.e. acute myocardial infarction (n=38) or an episode of unstable angina (n=27). METHODS and 24 h ambulatory ECG recordings were obtained from 65 patients randomized to either a 3 months supervised outpatient group training programme 50 min three times a week (n=29) or to a control group (n=36). The two groups were well balanced as regards demographic data and pharmacological treatment at the time of randomization. Body mass index and pharmacological therapy remained unchanged during the study. Heart rate variability was analysed in the time and frequency domains. At the 3 month follow-up, exercise tolerance had increased from 103 to 120 W in the training group (P<0.001), and from 102 to 106 W in the control group (ns). The time-domain heart rate variability measures SDNN (standard deviation of all filtered RR intervals over the analysed time period) and SDANN (standard deviation of the means of all filtered RR intervals for all 5 min epochs of the analysed time period) increased significantly during the daytime in the training group (P<0.01 and P<0.05, respectively), but not in the control group. A significant improvement in night-time heart rate variability was observed among controls. There was a statistically significant correlation (P<0.05) between changes in 24 h overall power (frequency domain measure) and changes in maximal exercise capacity in the training group. A regular aerobic group training programme after an acute coronary event can significantly improve exercise capacity and modify heart rate variability in a prognostically favourable direction in elderly low-to-intermediate risk patients, recovering from an acute coronary event.
Article
Unlabelled: Cryotherapy as a whole-body cold therapy (with cold air cooled by addition of nitrogen blown on the patients in an open cabin) for treatment of inflammatory rheumatic diseases already started in Bad Säckingen in 1986. In 1996, a new cold chamber (this time a closed chamber without any addition of nitrogen) based on compressor technology was introduced. The aim of our study was to test whether significant pain relief could be achieved by means of this cold therapy. Furthermore, we were interested in the practicability and acceptance of this new technique. Wellbeing during the treatment application and pain level were assessed using verbal and numerical rating scales. The sample consisted of 120 consecutive patients (75% women, age: 30-67 yrs, M = 52.6 yrs). These patients were suffering from primary fibromyalgia (40.7%), rheumatoid arthritis (17.3%), chronic low back pain (16.4%), ankylosing spondylitis (10.9%), osteoarthritis (9.1%), secondary fibromyalgia (3.6%) and other autoimmune diseases (1.8%) (mean duration of symptoms: 4 yrs). The patients were treated 2.5 minutes on average in the main chamber (mean temperature: -105 degrees C). The patients' statements concerning their pain level were analyzed by means of analyses of variance with repeated measures and paired-sample t-tests. Results: The pain level after application of the cold therapy decreases significantly. The pain reduction lasts about 90 minutes. The initial pain level decreases during the whole time of treatment, no significant improvement, though, can be shown from the middle to the end of the four-weeks treatment. According to the results of our study, there is evidence that the whole-body cold therapy generates important short-term effects and somewhat weaker effects over the treatment period as a whole. Short-term pain reduction facilitates intensive application of physiotherapy and Occupational Therapy. The treatment procedure is practicable, and all in all well tolerated. From the patients' point of view, whole-body cold therapy is an essential part of the rehabilitation programme.
Article
This study deals with the adaptation of the sympathoadrenal responses to an acute cold water immersion in ordinary winter swimmers. Hormonal responses were determined at the beginning of the winter swimming period in the autumn and after regular swimming for one and three months. Water temperature in the river was 10 degrees C at the beginning and 4 degrees C after one and three months. The mean duration of the test immersion was 36 s. Plasma catecholamine levels determined before the test immersion decreased with the winter swimming period for one month (NA, p < 0.001, A, p < 0.01). The test immersion significantly increased noradrenaline levels (p < 0.001). Plasma adrenaline and serum cortisol levels were increased or decreased by the immersion. After 1 month's swimming the test immersion to 4 degrees C increased noradrenaline to a similar level than the immersion to 10 degrees C at the beginning. Regularly practiced winter swimming for three months led to diminished catecholamine levels measured immediately after the test immersion (p < 0.01). The results suggest that cold adaptation induced by winter swimming attenuates the catecholamine responses to cold water. Adrenaline responses are also affected by its level prior to the immersion.
Article
The cold face test (CFT) is a non-invasive challenge maneuver of the autonomic nervous system which activates the peripheral sympathetic and the cardiac parasympathetic nervous system and induces peripheral vasoconstriction and bradycardia. The physiology of CFT-induced bradycardia is still controversial. The heart rate decrease might result from a direct central up-regulation of cardiovagal activity or might be a secondary effect of baroreceptor activation or of changes of respiration. The purpose of this study was to analyze the origin of CFT-induced bradycardia. To evaluate the influence of respiration on bradycardia during CFT, we studied cardiac responses in 10 healthy volunteers during CFT (0–1 °C cold compresses for 60 s) with three different respiratory patterns: one with spontaneous and two with paced respiration (6 and 15 cycles/minute). We continuously monitored heart rate (HR), blood pressure (BP) and respiration and determined heart rate variability by assessment of coefficient of variation (CV), standard deviation (SD) and the root mean square of successive differences (RMSSD) of HR as well as low (LF) and high (HF) frequency spectra power of HR and BP. When coherence was above 0.5, we calculated the transfer function gain between HR and respiration in the HF band, as an index of respiratory sinus arrhythmia, and between HR and BP in the LF band, as an index of baroreflex sensitivity. HR decreased and BP increased significantly during the three types of CFT. The decrease of HR and the increase of BP, of time and frequency domain parameters did not differ between the three breathing patterns. Respiration, and HF and LF power of respiration did not change during CFT. The gain of the HF-transfer function between HR and respiration and the LF-transfer function gain between HR and BP increased significantly during CFT, but the increase did not differ between the three breathing patterns. The increase of the gain of both transfer functions is most likely due to an increase of vagal traffic and together with the unchanged respiratory pattern suggests that CFT-induced bradycardia is not due to baroreflex or respiratory influences, but seems to result from central vagal activation.
Article
Rheumatoid arthritis may be associated with an increased risk of cardiovascular disease. We compared the incidence rates of myocardial infarction and stroke in subjects with and without rheumatoid arthritis. A prospective cohort study was conducted among the 114 342 women participating in the Nurses' Health Study who were free of cardiovascular disease and rheumatoid arthritis at baseline in 1976. All self-reported cases of rheumatoid arthritis were confirmed by medical record review. Fatal and nonfatal myocardial infarctions and strokes were similarly confirmed. Multivariate pooled logistic regression was used to adjust for potential cardiovascular risk factors. Five hundred twenty-seven incident cases of rheumatoid arthritis and 3622 myocardial infarctions and strokes were confirmed during 2.4 million person-years of follow-up. The adjusted relative risk of myocardial infarction in women with rheumatoid arthritis compared with those without was 2.0 (95% confidence interval [CI], 1.23 to 3.29). For stroke, the adjusted relative risk was 1.48 (95% CI, 0.70 to 3.12). Women who had rheumatoid arthritis for at least 10 years had a risk for myocardial infarction of 3.10 (95% CI, 1.64 to 5.87). In this large prospective cohort of women, participants with rheumatoid arthritis had a significantly increased risk of myocardial infarction but not stroke compared with those without rheumatoid arthritis. If these data are confirmed, aggressive coronary heart disease prevention strategies should be tested for persons with rheumatoid arthritis.
Article
Occupational or recreational exercise reduces mortality from cardiovascular disease. The potential mechanisms for this reduction may include changes in blood pressure (BP) and autonomic control of the circulation. Therefore, we conducted the present long-term longitudinal study to quantify the dose-response relationship between the volume and intensity of exercise training, and regulation of heart rate (HR) and BP. We measured steady-state hemodynamics and analyzed dynamic cardiovascular regulation by spectral and transfer function analysis of cardiovascular variability in 11 initially sedentary subjects during 1 yr of progressive endurance training sufficient to allow them to complete a marathon. From this, we found that 1) moderate exercise training for 3 mo decreased BP, HR, and total peripheral resistance, and increased cardiovascular variability and arterial baroreflex sensitivity; 2) more prolonged and intense training did not augment these changes further; and 3) most of these changes returned to control values at 12 mo despite markedly increased training duration and intensity equivalent to that routinely observed in competitive athletes. In conclusion, increases in R-wave-R-wave interval and cardiovascular variability indexes are consistent with an augmentation of vagal modulation of HR after exercise training. It appears that moderate doses of training for 3 mo are sufficient to achieve this response as well as a modest hypotensive effect from decreasing vascular resistance. However, more prolonged and intense training does not necessarily lead to greater enhancement of circulatory control and, therefore, may not provide an added protective benefit via autonomic mechanisms against death by cardiovascular disease.
Article
We studied the effect of regular physical activity on cardiac and vascular autonomic modulation during a 5-yr controlled randomized training intervention in a representative sample of older Finnish men. Heart rate variability (HRV) and blood pressure variability (BPV) are markers of cardiac and vascular health, reflecting cardiac and vascular autonomic modulation. One hundred and forty randomly selected 53- to 63-yr-old men were randomized into two identical groups: an intervention (EX) group and a reference (CO) group, of which 89 men remained until the final analysis (EX: n = 47; CO: n = 42). The EX group trained for 30-60 min three to five times a week with an intensity of 40-60% of maximal oxygen consumption. The mean weekly energy expenditure of the training program for the 5-yr training period was 3.80 MJ, and 71% of the EX group exceeded the mean. The EX group had a significantly (P < 0.01) higher oxygen consumption at ventilatory aerobic threshold (VO2VT) than the CO group at the 5-yr time point. VO2VT had a tendency to increase in the EX group and decrease in the CO group (interaction P < 0.001) from the baseline to the 5-yr time point. Peak performance did not change. Low-frequency power of R-R interval variability decreased in the EX group (P < 0.01, by 6%) from the baseline to the 5-yr time point. BPV did not change. In conclusion, low-intensity regular exercise training did not prevent HRV from decreasing or change BPV in 5 yr in older Finnish men.
Article
Chronic exercise training has been shown to have a positive influence on cardiac autonomic function as assessed by measures of heart rate variability (HRV). Recent evidence indicates that several benefits associated with exercise training (e.g., improved insulin action, reduced blood pressure, improved blood lipid profile) may be realized transiently after a single bout of exercise. As many of these effects of recent exercise are linked to cardiovascular control systems, the purpose of this investigation was to test the hypothesis that a single bout of exercise would result in favorable changes in cardiac autonomic function as assessed by frequency-domain measures of HRV. Subjects were 11 healthy male volunteers ages 18-35 yr. Resting HRV measures were obtained during 5 min of paced breathing before and 1, 3, 6, and 22 h after a 60-min bout of cycling exercise at approximately 65% of peak oxygen uptake. Identical measures were obtained in a nonexercise condition based on a randomized crossover design. Exercise resulted in increased high-frequency HRV, decreased low-frequency HRV, and consequently a decrease in the ratio of low-frequency to high-frequency HRV compared with the nonexercise condition. Additionally, a time-domain measure of HRV (pNN50) was markedly higher in the exercise condition as compared to nonexercise. The changes in cardiac autonomic function observed are similar to those seen in investigations of long-term training. These changes indicate a shift in autonomic function toward increased parasympathetic nervous system activity and decreased sympathetic nervous system activity, suggesting a more stable autonomic environment for the heart. These results may provide further evidence of the cardioprotective effects of a single bout of submaximal exercise.
Ganzkörperkältetherapie in einer Kältekammer mit Temperaturen um −110°C
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