Article

Effect of Regular Winter Swimming on the Activity of the Sympathoadrenal System Before and After a Single Cold Water Immersion

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Abstract

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.

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... Several studies have suggested that cold water swimming has a wide variety of health benefits [3], including changes in hematological [4] and endocrine function [5,6], fewer upper respiratory tract infections [7], amelioration of mood disorders [8] and general well-being [9]. Although chronic exposure to colder water temperatures has been shown to be beneficial to one's health, several studies have outlined the potential risks [10][11][12][13]. ...
... In Eastern Europe and Russia, winter swimming is part of the celebration of Epiphany [21]. Naturally, many field studies investigating the influence of cold water swimming on the body come from these northern countries on various topics such as adaptation to the cold [22], changes in lipid metabolism [23,24], adjustments to hematological values [25,26], effects on the immune system [27][28][29][30] and the hormones [5,31] or aspects of thermoregulation [32][33][34][35]. Events in which large numbers of people swim over a relatively short distance in cold water in winter can also be called classic winter swimming. ...
... Swimming in cold water also affects other hormones, such as ACTH and catecholamines [5,58]. As such, it was found that if swimmers participated in winter swimming three times a week at water temperatures of 0-3 • C for 12 weeks, there was an increase in ACTH and cortisol as well as norepinephrine [58]. ...
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Cold water swimming (winter or ice swimming) has a long tradition in northern countries. Until a few years ago, ice swimming was practiced by very few extreme athletes. For some years now, ice swimming has been held as competitions in ice-cold water (colder than 5 °C). The aim of this overview is to present the current status of benefits and risks for swimming in cold water. When cold water swimming is practiced by experienced people with good health in a regular, graded and adjusted mode, it appears to bring health benefits. However, there is a risk of death in unfamiliar people, either due to the initial neurogenic cold shock response or due to a progressive decrease in swimming efficiency or hypothermia.
... Many winter swimmers argued that the cold water helps withstand pain, refreshes one from general tiredness, improves one's mood and improves those who suffer from chronic diseases such as rheumatoid arthritis and fibromyalgia (4). Other benefits which have been mentioned by active winter swimmers is the prevention of virus infections and the improvement of general wellbeing (3). ...
... The refreshing effect of winter swimming is related with to the activation of the sympathetic nervous system and W Wi in nt te er r S Sw wi im mm mi in ng g I In n G Gr re ee ec ce e the increase in the mean concentration of noradrenaline, cortisol, TSH and thyroid hormones (1,2,4,5). Winter swimmers also supports that even a short dip in the cold water, can strengthen the human body and thus it can withstand other kinds of stress. This reaction may be the result is the functioning of both the autonomic and central nervous system, where neuronal transmitters such as endorphins, noradrenaline, dopamine and serotonin, plays a crucial role in the pain threshold and mood (8). ...
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... 4-krot ne roz sze rze nie na czyń krwio no śnych i sil ne prze krwie nie tka nek [1,10] . Do kli nicz nych efek tów po ja wia ją cych się wsku tek dzia ła nia ni skich tem pe ra tur mo że my za li czyć m.in.: ła go dze nie bó lu [11], sta nów za pal nych [12,13] , wzmoc nie nie obro ny an ty ok sy da cyj nej [14], zmniej sza nie obrzę ków [15] i do le gli wo ści ze stro ny mię śni [16,17], wzrost wy dzie la nia nie któ rych hor mo nów [18] oraz po pra wę sa mo po czu - cia [1,19]. Ką pie le w zim nej wo dzie, po przez swój ...
... A few minutes after the exposure the compensatory responses take place, involving opposite body behaviours compared with the first phase, including: fourfold vasodilatation and substantial tissue congestion [1,10]. The clinical effects of low temperatures include: alleviation of pain [11] and inflammatory conditions [12,13], enhancement of antioxidative defence [14], reduction of swelling [15] and muscle ailments [16, 17], an increased excretion of some hormones [18] and improvement of well-being [1,19]. Bathing in cold water, through its effect on the circulatory and im mune system, may also lead to changes in blood mor phology. ...
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of adaptive responses in the body, especially in the circulatory system. The aim of this study was to determine the effect of bathing in cold water on blood morphology. Material and methods. The sample was composed of 30 people: fourteen winter swimmers regularly bathing in cold water, and sixteen amateurs who were not subjected to such treatments before. On the day of the experiment all subjects spent 3 minutes in water at the temperature of 0°C with an ambient temperature of -4°C. Blood samples were taken before exposure to low temperatures (control) as well as 5 and 30 min after bathing in cold water. The basic parameters of peripheral blood: RBC, HGB, HCT, MCV, MCH, MCHC, WBC and PLT were estimated using an automatic hematological analyzer. Results. The study showed a slight increase in mean corpuscular hemoglobin concen - tration (MCHC) in winter swimmers and lower mean corpuscular volume (MCV) in ama - teurs 30 min after bathing in cold water vs. the control study. Comparison of the studied groups showed a higher mean MCV value in winter swimmers 5 min after cold bath, and a higher leukocyte count in amateurs 30 min after bathing in ice-cold water. Conclusions. Bathing in cold water affects some blood morphological parameters which may result from changes in the circulating blood in exposure to low ambient tem - peratures. A larger number of leukocytes observed in amateurs may prove an intensified immune response after cooling of the body.
... Huttunen i wsp. [14] swoimi badaniami wykazali, że wielokrotna ekspozycja na zimno powoduje mniejszy wzrost stężenia katecholamin aniżeli pojedynczy zabieg, a Jansky i wsp. [11] brak zmian w zakresie reaktywności współczulnego układu nerwowego. ...
... In their study, which included patients with inflammatory rheumatic conditions exposed to a temperaturę of -110°C for 2-3 minutes, the levels of ACTH, STH, cortisol or adrenalinę were not found to have changed, with the exception of noradrenaline, whose concentration increased slightly. A study by Huttunen et al. [14] demon-strated that repeated exposure to cold caused smaller increases in catecholamine concentration than a single treat-ment, while Jansky et al. [11] showed no changes in sym-pathetic reactivity. ...
Article
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Background. Whole-body cryotheraphy has been used by sports professionals as a training adjunct for many years. As bibliographic data presenting empirical research concerning this subject are limited, we carried out a study to evaluate the effect of whole-body cryotherapy on selected blood chemistry markers, including interieukin-1β (IL-1β), in professional athletes. Material and methods. The study enrolled 11 Polish men's national field hockey team members aged 25.8 ± 2.9 years (min. 21, max 31 yrs). Whole-body cryotherapy was administered twice a day (at temperatures from -120°C to -130°C) for 2.5-3 minutes, for a total of 18 procedures. In addition, all participants attended a general fitness training session in a gymnasium after each cryotherapy procedure. Blood chemistry determinations (erythrocyte sedimentation rate - ESR, leukocyte count - WBC, erythrocyte count - RBC, platelets, haemoglobin - HGB, haematocrit - HCT, MCV, MCH, MCHC, percentage of lymphocytes, monocytes and neutrophils, and interieukin-1β levels) were performed at baseline and on completion of the series of 18 cryotherapy procedures as well as one week later. Results and Conclusions. Whole-body cryotherapy significantly decreased the RBC, HGB and HCT parameters in peripheral blood. The decrease was, however, not permanent and after one week the parameters returned to baseline values (RBC, HCT) or were increased in comparison to baseline values (HGB). Whole-body cryotherapy was not found to have an immunomodulatory effect in the study group (WBC, percentage of lymphocytes, monocytes or neutrophils, IL-1β levels), except for its effect on the erythrocyte sedimentation rate (ESR), which did not change immediately after the treatment but was significantly lower one week later.
... 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]. The acute effects of WBC are related to reduction of resting heart rate and increase in stroke volume [16], stimulates autonomic nervous parasympathetic activity and increases norepinephrine [18,46]. ...
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.
... Address author correspondence to Flora Bird at florabird1@gmail.com. neurogenic pathways have been implicated in producing this habituation (Griffin, 1963;Tipton, Golden, Higenbottam, Mekjavic, & Eglin, 1998), and evidence of a sympathoadrenal adaption has been shown in regular cold water swimmers pre-and postimmersion (Huttunen, Rintamäki, & Hirvonen, 2001). ...
Article
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Habituation of the cold shock response and adaptation in deep body cooling with prolonged cold water immersion is well documented in adults. This study aimed to determine whether children exhibit similar adaptive responses. Eight children aged 10–11 years underwent a 5 min static immersion in 15 °C (59 °F) water, five then swam for up to 40 min, before and after a year of regular cold water swim training. Following acclimatization, no differences were found in heart rates or respiratory frequencies on initial immersion, despite a smaller relative V ˙ O 2. Children reported feeling warmer (p < .01) and more comfortable (p < .05), implying acclimatization of subjective perception of cold. No difference was found in cooling rates while swimming. On comparison with data of adults swimming in 12 °C (53.6 °F) water, no difference was found in cooling rates, but the trend in both acclimatized groups to a slower rate of cooling was significant (p ≤ .026) when the data were pooled. These data may support a theory of insulative adaptation.
... The increase of some catecholamines after whole-body exposure to cold water was observed by some authors (Leppäluoto et al., 2008;Vybiral et al., 2000). Huttunen et al. (2001) postulated that attenuation of the catecholamine responses to cold water observed during winter swimming season may be an element of adaptation to Table 5 Heart rate measured before, during and after exposure to cold water in form of winter swimming (WS) in people regularly taking baths in freezing water (regular winter swimmers) and in those who practiced it for the first time (novice winter swimmers). ...
... Although the aforementioned data suggests that incidental immersion in cold water can be harmful, regular exposure to low temperatures is known to be associated with increased tolerance to cold due to numerous adaptive mechanisms. Several authors have observed a decrease in the levels of catecholamines as a result of regular swimming in cold water [14,16]. Also, the existence of potential mechanism protecting the tissues of winter swimmers against free radical mediated injury has been postulated [30]. ...
Article
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The aim of this study was to analyze the changes in blood rheology resulting from regular winter swimming. The study was carried out on 12 male winter swimmers. Venous blood for morphological, biochemical and rheological analysis was sampled twice from each winter swimmer - at the beginning of the season and after its completion. There were no significant changes detected in the median values of most blood morphological parameters. The only exception pertained to MCHC which was significantly lower after the season. Winter swimming entailed significant decrease in median elongation index values at shear stress levels of 0.30 Pa and 0.58 Pa, and significant increase in median values of this parameter at shear stress levels ≥1.13 Pa. No significant changes were observed in winter swimmers' median values of aggregation indices and plasma viscosity. The median level of glucose was lower post winter swimming in comparison to the pre-seasonal values. In contrast, one season of winter swimming did not influence swimmers' median value of fibrinogen concentration. In summary, this study revealed positive effects of winter swimming on the rheological properties of blood, manifested by an increase in erythrocyte deformability without accompanying changes in erythrocyte aggregation.
... These include exercise, 27 30 This generalised response to CWI includes the release of cortisol 39 and increased secretion of the catecholamines. 36 However, not all studies have shown this to be the case. 40 The interaction between the nervous system and the endocrine system is complicated and shows much inter-and intra-variability. ...
Article
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Background An increasing volume of anecdotal and scientific evidence suggests that mood may be enhanced following swimming in cold water. The exact mechanisms responsible are largely unknown, but may include the effects of exercise from swimming and the effects of cold. This study examined the effect on mood following immersion in cold water, where swimming was not the primary activity. Methods The Profile of Mood States (POMS) questionnaire was completed by 64 undergraduate students. The following week, 42 participants completed up to 20-min immersion (18ʹ36ʺ ± 1ʹ48ʺ) in cold sea water (13.6°C). Twenty-two participants acted as controls. The POMS was completed immediately following the cold-water immersion by both groups. Results The cold-water immersion group showed a significant decrease, with a large effect size, of 15 points from 51 to 36, compared to 2 points in the control group, 42 to 40. Positive sub-scales increased significantly in the cold-water immersion group (Vigour by 1.1, and Esteem-Related Affect by 2.2 points) and negative sub-scales showed significant reductions (Tension by 2.5, Anger 1.25, Depression 2.1, Fatigue 2.2, and Confusion 2.8 points). The control showed no significant change except for depression, which was significantly higher after the period by 1.6 points. Conclusion Cold-water immersion is a well-tolerated therapy that is capable of significantly improving mood in young, fit, and healthy individuals. A key aim of this study was to control for the effects of swimming as a mechanism responsible for the improvement in mood which has been shown in previous studies. Thus, the change in mood evidenced in this study was not due to physical activity per se. Consequently, the hypothesis that cold in and of itself can improve mood is supported.
... While acclimatization has some cardiorespiratory effects it does not appear to have a major effect on thermal status, which is also the case for plasma renin-angiotensin activity and aldosterone concentrations (181). Chronic HOWI in 10 • C to 4 • C water for three months resulted in decreased catecholamine response to cold HOWI (174). ...
Article
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Water covers over 70% of the earth, has varying depths and temperatures and contains much of the earth's resources. Head-out water immersion (HOWI) or submersion at various depths (diving) in water of thermoneutral (TN) temperature elicits profound cardiorespiratory, endocrine, and renal responses. The translocation of blood into the thorax and elevation of plasma volume by autotransfusion of fluid from cells to the vascular compartment lead to increased cardiac stroke volume and output and there is a hyperperfusion of some tissues. Pulmonary artery and capillary hydrostatic pressures increase causing a decline in vital capacity with the potential for pulmonary edema. Atrial stretch and increased arterial pressure cause reflex autonomic responses which result in endocrine changes that return plasma volume and arterial pressure to preimmersion levels. Plasma volume is regulated via a reflex diuresis and natriuresis. Hydrostatic pressure also leads to elastic loading of the chest, increasing work of breathing, energy cost, and thus blood flow to respiratory muscles. Decreases in water temperature in HOWI do not affect the cardiac output compared to TN; however, they influence heart rate and the distribution of muscle and fat blood flow. The reduced muscle blood flow results in a reduced maximal oxygen consumption. The properties of water determine the mechanical load and the physiological responses during exercise in water (e.g. swimming and water based activities). Increased hydrostatic pressure caused by submersion does not affect stroke volume; however, progressive bradycardia decreases cardiac output. During submersion, compressed gas must be breathed which introduces the potential for oxygen toxicity, narcosis due to nitrogen, and tissue and vascular gas bubbles during decompression and after may cause pain in joints and the nervous system. © 2015 American Physiological Society. Compr Physiol 5:1705-1750, 2015.
... Address author correspondence to Flora Bird at florabird1@gmail.com. IJARE Vol. 9, No. 2, 2015 neurogenic pathways have been implicated in producing this habituation (Griffin, 1963;Tipton, Golden, Higenbottam, Mekjavic, & Eglin, 1998), and evidence of a sympathoadrenal adaption has been shown in regular cold water swimmers pre-and postimmersion (Huttunen, Rintamäki, & Hirvonen, 2001). ...
Article
Full-text available
Habituation of the cold shock response and adaptation in deep body cooling with prolonged cold water immersion is well documented in adults. This study aimed to determine whether children exhibit similar adaptive responses. Eight children aged 10–11 years underwent a 5 min static immersion in 15 °C (59 °F) water, five then swam for up to 40 min, before and after a year of regular cold water swim training. Following acclimatization, no differences were found in heart rates or respiratory frequencies on initial immersion, despite a smaller relative V˙O2. Children reported feeling warmer (p < .01) and more comfortable (p < .05), implying acclimatization of subjective perception of cold. No difference was found in cooling rates while swimming. On comparison with data of adults swimming in 12 °C (53.6 °F) water, no difference was found in cooling rates, but the trend in both acclimatized groups to a slower rate of cooling was significant (p ≤ .026) when the data were pooled. These data may support a theory of insulative adaptation.
... 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.
... Cette coutume est relativement ancienne et était réalisée pour des raisons de santé. Pour ces nageurs de tout âge, l'immersion en eau très froide permet de diminuer les risques de tomber malade et d'améliorer leur tolérance face au stress de la vie quotidienne(Dugue and Leppanen, 2000;Huttunen et al., 2001). La seconde méthode utilisée proche de la natation en eau froide est l'immersion en eau froide. ...
Thesis
Cette thèse a été effectuée sous le couvert d’une convention CIFRE issue d’une collaboration entre la Société Cryantal (Lognes, France) et les laboratoires universitaires C3S (EA 4660) et MOVE (EA 6314) de Franche-Comté et de Poitiers. Elle a été articulée autour du développement d’une nouvelle technologie de chambre de Cryothérapie Corps Entier (CCE). Le travail mené au cours de ces quatre années a eu pour objectifs : 1) L’identification des besoins technologiques et méthodologiques à partir d’études conduites sur le terrain et de l’analyse de la littérature scientifique ; 2) Le développement d’un prototype de chambre CCE à partir des besoins identifiés ; 3) La validation technologique du prototype en vue de son industrialisation ; 4) D’apporter des perspectives d’évolutions futures pour le développement du prototype afin qu’il devienne une chambre CEE commercialisable. Afin de répondre à ces objectifs, la thèse a été divisée en deux parties distinctes.La première partie met en évidence les applications pratiques et les besoins technologiques afin d’identifier les limites et avantages des différentes méthodes et techniques utilisées en vue du développement d’un nouveau prototype de chambre CCE. Les études conduites sur le terrain dans les conditions réelles de compétition ont montré que la CCE n’était pas vécue comme une contrainte importante par les athlètes et qu’elle leur permettait d’améliorer la qualité de leur sommeil perçu. Nous avons également montré que des individus avec un indice de masse corporel moins élevé supportaient moins bien les expositions au froid extrême en cabine comparé à ceux possédant un indice de masse corporel plus important. La revue de littérature scientifique a mis en évidence le manque crucial de données valides concernant les températures d’exposition dans les chambres et cabines. Elle pointe également pour la première fois, l’ensemble des protocoles d’expositions utilisés à ce jour dans les domaines d’applications relatifs aux pathologies traumatiques et de récupération physique. Elle crée le lien indispensable entre les différents domaines d’utilisation de la CCE et les différentes technologies utilisées.La seconde partie expose l’ensemble du développement technologique du prototype de la nouvelle chambre CCE, sa validation et son optimisation pour pouvoir prétendre à sa commercialisation. Elle comporte une étude scientifique de validation technologique du prototype de chambre de CCE basé sur la variation de la température cutanée des individus exposés. Les résultats ont montré que les variations de température cutanée engendrées par l’exposition avec la nouvelle technologie étaient similaires aux variations rapportées avec les autres technologies existantes. Les mesures préliminaires réalisées sur le prototype ont permis d’apporter des perspectives d’évolutions futures en vue de la commercialisation de la chambre.
... Address author correspondence to Flora Bird at florabird1@gmail.com. IJARE Vol. 9, No. 2, 2015 neurogenic pathways have been implicated in producing this habituation (Griffin, 1963;Tipton, Golden, Higenbottam, Mekjavic, & Eglin, 1998), and evidence of a sympathoadrenal adaption has been shown in regular cold water swimmers pre-and postimmersion (Huttunen, Rintamäki, & Hirvonen, 2001). ...
... The authors concluded that BP and plasma catecholamine levels decreased during winter swimming practice over one winter, but similar, albeit to a lesser degree, changes also were observed in the control persons; whether these humoral changes reflect adaptation to cold or seasonal variation was not clear (40). Another study indicated that cold adaptation induced by winter swimming attenuates the catecholamine responses to cold water (43). ...
Article
Winter swimming is a stressful condition of whole-body exposure to cold water; however, winter swimmers have achieved variable degrees of adaptation to cold. The question arises whether this extreme sport activity has any health benefits or whether it may confer potentially harmful effects. As a form of aerobic exercise, albeit more strenuous when performed in cold water, winter swimming may increase body tolerance to stressors and achieve body hardening. When practiced by individuals who are in good general health adopting a regular, graded and adaptive mode, winter swimming seems to confer cardiovascular (CV), and other health benefits. On the other hand, unaccustomed individuals are at risk of death either from the initial neurogenic cold-shock response, or from progressive decrease of swimming efficiency or from hypothermia. Furthermore, as it may occur with any intense exercise, individuals with evident or occult underlying CV conditions may be more susceptible to adverse effects with provocation of arrhythmias and CV events that may pose a significant health risk. Hence, a stepwise strategy to initiate and build up this recreational activity is recommended to enhance and sustain acclimation, achieve protection from potential risks of cold-water exposure and possibly avail from its promising health benefits. We need more data from prospective studies to better investigate the short- and long-term health consequences of this important recreational activity.
... WBC and PBC treatments are used to relieve depression and anxiety syndromes . Previously, investigations in winter swimmers were performed to assess the effect of cold on well-being Huttunen et al., 2001). In these studies, the adaption to cold was associated with a decrease in tension and fatigue and with an improvement in mood and memory. ...
Article
Noradrenaline released from sympathetic nerve endings and adrenaline secreted by the adrenal cortex have been shown to play roles in cold adaptation. The calorigenic effect of noradrenaline increases during acclimation. Catecholamines stimulate noncontractile thermogenesis in brown fat tissue, white fat tissue, and skeletal muscle. Adrenergic increases in cold tolerance are associated with increases in UCP expression in the tissues. The following signal pathway operates in mediating the calorigenic effect of catecholamines in prolonged cold exposure: catecholamines → β-adrenergic receptors → adenylate cyclase, cAMP → protein kinase A → p38 kinase → transcription factors → increased UCP expression. The following signal pathway operates on acute exposure to cold: catecholamines → β-adrenergic receptors → adenylate cyclase → cAMP → protein kinase A → hormone-sensitive lipase → free fatty acids → UCP → uncoupling of oxidative phosphorylation. The calorigenic effect of stimulation of α1-adrenoreceptors is mediated by the following mechanism: noradrenaline → α1-adrenergic receptors → phospholipase C → inositol-1,4,5-triphosphate → [Ca2+]i → increased calorigenic effect of catecholamines.
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.
Article
This study deals with the effects of regular winter swimming on the mood of the swimmers. Profile of Mood State (POMS) and OIRE questionnaires were completed before (October) and after (January) the four-month winter swimming period. In the beginning, there were no significant differences in the mood states and subjective feelings between the swimmers and the controls. The swimmers had more diseases (about 50%) diagnosed by a physician. Tension, fatigue, memory and mood negative state points in the swimmers significantly decreased with the duration of the swimming period. After four months, the swimmers felt themselves to be more energetic, active and brisk than the controls. Vigour-activity scores were significantly greater (p < 0.05). All swimmers who suffered from rheumatism, fibromyalgia, or asthma, reported that winter swimming had relieved pains. Improvement of general well-being is thus a benefit induced by regular winter swimming.
Article
Swimming in cold water during the winter season is an extreme sport, with fans all over the world. However, its effects on health have been debated. This article examines the hypothesis that the effects of winter swimming may depend on previous exposure to cold stimuli. Immersion in cold water in unaccustomed persons may lead to detrimental consequences, while, in regular winter swimmers, adaptive physiologic mechanisms increase tolerance to cold. Furthermore, these mechanisms may prevent the occurrence of a wide variety of diseases. Prospective studies and epidemiological data are needed to test this hypothesis.
Article
Background: Chronic heart failure is characterized by increased peripheral vascular resistance and reduced peripheral perfusion due to adrenergic and renin angiotensin activation and impaired endothelial function. Recent studies have shown that nonpharmacological peripheral vasodilation with thermal therapy by means of warm-water baths and sauna has beneficial effects in chronic heart failure. European hydrotherapy (according to Kneipp) additionally uses short cold water stimuli, which lead to prolonged vasodilation and adaptive responses. Studies on the efficacy of hydrotherapy in chronic heart failure are lacking. Methods: We studied 15 patients (5 men, 10 women, mean (+/- SD) age 64.3 +/- 1.8 years) with mild chronic heart failure (NYHA functional class II to III, ejection fraction 30%-40%). Patients were randomly assigned to 6 weeks of intensive home-based hydrotherapy or 6 weeks restriction in a crossover intervention trial. Quality of life and heart-failure--related symptoms were assessed by means of a validated questionnaire (PLC). Graded bicycle exercise test with incremental workloads (0, 50, 75, 100 watts) was performed at the end of each treatment period. The hydrotherapeutic program consisted of a structured combination of daily home-based external warm- and cold-water applications. Results: Baseline characteristics were balanced between the groups. With hydrotherapy, a significant (P < or =.05) improvement in 3 of 6 dimensions of quality of life (mood, physical capacity, enjoyment) and a significant reduction in heart-failure-related symptoms was found. Heart rates at rest and at 50-Watt workload were significantly reduced by hydrotherapy; blood pressure decreased nonsignificantly at rest and during exercise. The hydrotherapeutic treatment was well accepted and no relevant adverse effects were observed. Conclusions: A home-based hydrotherapeutic thermal treatment program improves quality of life, heart-failure-related symptoms and heart rate response to exercise in patients with mild chronic heart failure. The results of this investigation suggest a beneficial adaptive response to repeated brief cold stimuli in addition to enhanced peripheral perfusion due to thermal hydrotherapy in patients with chronic heart failure.
Article
The study was a follow-up one, in which blood pressure and hormonal changes were investigated during one winter swimming season in winter swimmers (WSs) and non-swimmer controls on three occasions (autumn, winter and spring). Humoral results were compared to psychological traits recorded at the time of the three blood samplings. Mean systolic blood pressure of the WSs fell from 134 +/- 12 mmHg to 128 +/- 12 mmHg (p < 0.05) during the winter, and a slight but non-significant drop was also seen in the controls. Mean plasma noradrenaline concentrations diminished significantly from autumn to spring, and more so in the WS-group, but no statistically significant difference was observed between the groups. Adrenaline levels also showed a decreasing trend, and the change was significant when calculated by using the combined means of both groups. Plasma homovanillic acid and beta-endorphin values were on the same level in all seasonal samples in both groups. Plasma serotonin levels decreased in both groups by about 50 per cent by spring, but 5-HIAA did not change significantly. HVA showed correlation with blood pressure and anxiety in the autumn (r=0.367). In the winter measurement endorphin and hysteria had a negative correlation (r=0.370). In the spring 5-HIAA and obsessionality had a positive correlation (r=0.351). In summary, blood pressure and plasma catecholamine levels decreased during winter swimming practice over one winter, but these changes were also observed in the control persons. Plasma serotonin was lower in the spring in both groups. The changes in the humoral status speak for adaptation to the research situation, or reflect seasonal variation from autumn to spring. No clear effect of winter swimming as such was detected.
Article
Cold-water immersion (CWI) is a popular recovery intervention after exercise. The scientific rationale is not clear, and there are no clear guidelines for its use. The aim of this review was to study the physiological and biochemical effect of short periods of CWI. A computer-based literature search, citation tracking and related articles searches were undertaken. Primary research studies using healthy human participants, immersed in cold water (<15 degrees C), for 5 min durations or less were included. Data were extracted on body temperature, cardiovascular, respiratory and biochemical response. 16 studies were included. Sample size was restricted, and there was a large degree of study heterogeneity. CWI was associated with an increase in heart rate, blood pressure, respiratory minute volume and metabolism. Decreases in end tidal carbon dioxide partial pressure and a decrease in cerebral blood flow were also reported. There was evidence of increases in peripheral catecholamine concentration, oxidative stress and a possible increase in free-radical-species formation. The magnitude of these responses may be attenuated with acclimatisation. CWI induces significant physiological and biochemical changes to the body. Much of this evidence is derived from full body immersions using resting healthy participants. The physiological and biochemical rationale for using short periods of CWI in sports recovery still remains unclear.
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Human adaptation to cold may occur through acclimatization or acclimation and includes genetic, physiologic, morphological or behavioural responses. It has been studied in indigenous populations, during polar or ski expeditions, sporting activities, military training, in urban people, or under controlled conditions involving exposures to cold air or water. Although divergent results exist between the studies, the main cold adaptation responses are either insulative (circulatory adjustments, increase of fat layer) or metabolic (shivering or nonshivering thermogenesis) and may be positive (enhanced) or negative (blunted). The pattern of cold adaptation is dependent on the type (air, water) and intensity (continuous, intermittent) of the cold exposure. In addition, several individual factors like age, sex, body composition, exercise, diet, fitness and health modify the responses to cold. Habituation of thermal sensations to cold develops first, followed by cardiovascular, metabolic and endocrinological responses. If the repeated cold stimulus is discontinued, adaptation will gradually disappear. The functional significance of physiological cold adaptation is unclear, and some of the responses can even be harmful and predispose to cold injuries. The article summarises recent research information concerning with the thermoregulatory responses related to repeated exposures to cold (air or water), and also discusses the determinants of cold adaptation, as well as its functional significance.
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The Scandinavian winter-swimming culture combines brief dips in cold water with hot sauna sessions, with conceivable effects on body temperature. We study thermogenic brown adipose tissue (BAT) in experienced winter-swimming men performing this activity 2–3 times per week. Our data suggest a lower thermal comfort state in the winter swimmers compared with controls, with a lower core temperature and absence of BAT activity. In response to cold, we observe greater increases in cold-induced thermogenesis and supraclavicular skin temperature in the winter swimmers, whereas BAT glucose uptake and muscle activity increase similarly to those of the controls. All subjects demonstrate nocturnal reduction in supraclavicular skin temperature, whereas a distinct peak occurs at 4:30–5:30 a.m. in the winter swimmers. Our data leverage understanding of BAT in adult human thermoregulation, suggest both heat and cold acclimation in winter swimmers, and propose winter swimming as a potential strategy for increasing energy expenditure.
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Winter swimming represents an intensive short-term exposure to cold, and thus it is considered a strong physical stress. Cold-based treatments, i.e. immersions in cold water, are spreading in sport medicine for improving recovery following muscle traumas, although a universal acceptance of that method is not still achieved. Fifteen healthy subjects (13 males and 2 females) were recruited among the participants to a 150 meters long swimming race in cold water (6 degrees C). Blood samples were collected the day before and immediately after the race and a panel of haematological parameters was evaluated. Swimming in cold water induced a significant variation in the blood cell fraction composition compared to the rest condition, as measured the day before the competition. Red blood cells, white blood cells and platelets count increased significantly (4.7%, P = 0.005; 40.6%, P < 0.001 and 25.0%, P < 0.001, respectively). While the relative number of leukocytes did not change significantly, apart from a strong decrease of the eosinophils population (-48.6%; P < 0.001), a strong increase in the total number of neutrophil granulocytes, lymphocytes and monocytes was recorded (42.6%, P = 0.002, 58.2%, P = 0.001 and 27.5%, P = 0.021, respectively). Following normalization on plasma volume change (-2.54%) the results were unchanged, demonstrating that the variations were not due to a mere haemoconcentration. When represented by brief exposure to cold water, winter swimming induces strong non-pathological modifications of haematological homeostasis.
Article
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.
Article
Cold therapy is used to relieve pain and inflammatory symptoms. Humoral changes may account for the pain alleviation related to the cold exposures. The aim of the present study was to examine the effects of two types of cold therapy, winter swimming in ice-cold water (WS) and whole body cryotherapy (WBC), on the serum levels of the growth hormone, prolactin, thyrotropin and free fractions of thyroid hormones (fT3, fT4). One group of healthy females (n = 6) was exposed to WS (water 0-2 degrees C) for 20 s and another group (n = 6) to WBC (air 110 degrees C) for 2 min, three times a week for 12 weeks. Blood samples used for the hormone measurements were taken on weeks 1, 4 and 12 before and 35 min after the cold exposures and on the days of the respective weeks, when the cold exposures were not performed. During the WS treatments, serum thyrotropin increased significantly at 35 min on weeks 1 (p < 0.01) and 4 (p < 0.05), but the responses were within the health-related reference interval. During the WS, the serum prolactin measured at 35 min on week 12 was lower than during the control treatment, and no changes in fT3 or fT4 were observed. During the WBC, no changes in the serum levels of the studied hormones were observed during the 12 weeks. In conclusion, repeated WS and WBC treatments for healthy females do not lead to disorders related to altered secretions of the growth hormone, prolactin, thyrotropin, or thyroid hormones
Article
Sudden death during whitewater recreation often occurs through understandable mechanisms such as underwater entrapment or trauma, but poorly defined events are common, particularly in colder water. These uncharacterized tragedies are frequently called flush drownings by whitewater enthusiasts. We believe the condition referred to as cold water immersion syndrome may be responsible for some of these deaths. Given this assumption, the physiologic alterations contributing to cold water immersion syndrome are reviewed with an emphasis on those factors pertinent to flush drowning.
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The harshest environment that many people will ever face is the critical care unit, where pathology can stress homeostatic mechanisms beyond their limits, leading to multiple organ failure and death. Our understanding of the biology that underlies this catastrophic process remains limited. There is significant variation in survival between individuals with apparently similar severity of organ dysfunction and it is difficult to predict which patients will weather the storm. Survival may be influenced by as yet undiscovered innate adaptive mechanisms that determine an individual's ability to tolerate physiological stress. Identifying favourable phenotypes, and the molecular machinery underlying them, could yield new therapeutic targets to improve outcome in life-threatening illness. Unfortunately, the complexity of critical illness makes it difficult to elucidate subtle adaptive mechanisms that could favour survival during stress. However, comparisons can be drawn between the stress of critical illness and that imposed by austere environments. The Earth is comprised of a wide range of different physical environments, each of which challenges homeostasis. Whilst technological advances have played a significant role in our capacity to survive in austere environments, biological adaptation and evolutionary change have been crucial. Studying human responses to environmental stressors such as heat, cold, hypoxia and microgravity has taught us a great deal about innate human adaptation, from the system to the cellular level, and the field continues to expand. Translating this to the pathophysiological stress of critical illness could offer alternative approaches to the current practice of intensive care medicine.
Article
Winter swimming is a game exercised in cold water, which induced body to produce strong stress response. This article reviewed the development of winter swimming on the mechanisms of body-building. Through scientific winter swimming exercise, the functions of cardiovascular, cerebral vessel and digest enhanced; the immune function increased, the index of blood rheology improved and the antioxidative capacity elevated in winter swimmers.
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Cold therapy is used to relieve pain and inflammatory symptoms. The present study was designed to determine the influence of long-term regular exposure to acute cold temperature. Two types of exposure were studied: winter swimming in ice-cold water and whole-body cryotherapy. The outcome was investigated on humoral factors that may account for pain alleviation related to the exposures. During the course of 12 weeks, 3 times a week, a group of healthy females (n = 10) was exposed to winter swimming (water 0-2 degrees C) for 20 s and another group (n = 10) to whole-body cryotherapy (air -110 degrees C) for 2 min in a special chamber. Blood specimens were drawn in weeks 1, 2, 4, 8 and 12, on a day when no cold exposure occurred (control specimens) and on a day of cold exposures (cold specimens) before the exposures (0 min), and thereafter at 5 and 35 min. Plasma ACTH and cortisol in weeks 4-12 on time-points 35 min were significantly lower than in week 1, probably due to habituation, suggesting that neither winter swimming nor whole-body cryotherapy stimulated the pituitary-adrenal cortex axis. Plasma epinephrine was unchanged during both experiments, but norepinephrine showed significant 2-fold to 3-fold increases each time for 12 weeks after both cold exposures. Plasma IL-1-beta, IL-6 or TNF alpha did not show any changes after cold exposure. The main finding was the sustained cold-induced stimulation of norepinephrine, which was remarkably similar between exposures. The frequent increase in norepinephrine might have a role in pain alleviation in whole-body cryotherapy and winter swimming.
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The effects of repeated cold water immersion on thermoregulatory responses to cold air were studied in seven males. A cold air stress test (CAST) was performed before and after completion of an acclimation program consisting of daily 90-min cold (18 degrees C) water immersion, repeated 5 times/wk for 5 consecutive wk. The CAST consisted of resting 30 min in a comfortable [24 degrees C, 30% relative humidity (rh)] environment followed by 90 min in cold (5 degrees C, 30% rh) air. Pre- and postacclimation, metabolism (M) increased (P less than 0.01) by 85% during the first 10 min of CAST and thereafter rose slowly. After acclimation, M was lower (P less than 0.02) at 10 min of CAST compared with before, but by 30 min M was the same. Therefore, shivering onset may have been delayed following acclimation. After acclimation, rectal temperature (Tre) was lower (P less than 0.01) before and during CAST, and the drop in Tre during CAST was greater (P less than 0.01) than before. Mean weighted skin temperature (Tsk) was lower (P less than 0.01) following acclimation than before, and acclimation resulted in a larger (P less than 0.02) Tre-to-Tsk gradient. Plasma norepinephrine increased during both CAST (P less than 0.002), but the increase was larger (P less than 0.004) following acclimation. These findings suggest that repeated cold water immersion stimulates development of true cold acclimation in humans as opposed to habituation. The cold acclimation produced appears to be of the insulative type.
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The present investigation is based on a 2.5 months selbstversuch (self-experiment) of the authors, between October 21 1992, and January 6 1993. 11 healthy students, five females and six males, age 24 to 29 years, and their teachers underwent regular winter swimming at least once a week, for 2 to 10 minutes, at the natural water temperature (6.8 degrees C (October 1992) to 2.0 degrees C (January 1993)) in the southern Baltic Sea. Blood samples were drawn before and 30 and 60 minutes after the cold bath, both at the first and the last day of the swimming season. TSH increased from 0.96 mU/l to 1.42 mU/l (p < 0.01) in the untrained, and from 0.93 mU/l to 1.43 mU/l (p < 0.01) in the cold-trained persons, and decreased thereafter (p < 0.01). Similar changes occurred in cortisol serum concentrations, though psychological stress seemed to interfere with cold stress. Cortisol increased from 99 ng/ml to 133 ng/ml in the untrained, and from 101 ng/ml to 137 ng/ml (p < 0.05) in the cold-trained persons within 30 minutes after cold water immersion, and decreased thereafter (p < 0.01). There were mild decreases in prolactin serum levels after cold stress, whereas FSH, LH and growth hormone remained unaltered. There was a mild initial elevation of serum glucose after cold stress (plus 12 mg/dl, (p < 0.01)) which disappeared after training. There were long term training effects besides the effects on glucose: Basal prolactin levels increased by almost the factor two, and insulin serum levels dropped by almost 50%.(ABSTRACT TRUNCATED AT 250 WORDS)
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The purpose of this study was to monitor changes in body and skin temperatures, heat production, subjective shivering, cold sensation and body fat content in humans after intermittent cold water immersion. Repeated exposures of young sportsmen to cold water (head out, 14 degrees C, 1 h, 3 times per week for 4-6 weeks) induced changes in regulation of thermal homeostasis. "Cold acclimated" subjects exhibited an hypothermic type of adaptation. Central and peripheral body temperatures at rest and during cold immersion were lowered. The metabolic response to cold was delayed and subjective shivering was attenuated. The observed hypothermia was due to the shift of the threshold for induction of cold thermogenesis to lower body temperatures. "Cold acclimated" subjects also showed a lowered cold sensation. Because of the observed physiological changes, about 20% of the total heat production was saved during one cold water immersion of "cold acclimated" subjects. Maximal aerobic and anaerobic performances were not altered. No change in the thermosensitivity of the body temperature controller, as assessed from the unchanged slope of the relation between the deep body temperature and total heat production, was observed. Changes in cold sensation and regulation of cold thermogenesis were noticed first after four cold water immersions and persisted for at least 2 weeks after termination of the adaptation procedure. A trend towards a small increase in the body fat content was also observed. This finding, as well as the increased vasoconstriction, evidenced by the lowered skin temperature, indicate that slight changes in body insulation may also occur after "cold acclimation" in humans.
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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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Adaptation to oxidative stress is an improved ability to resist the damaging effects of reactive oxygen species, resulting from pre-exposure to a lower dose. Changes in uric acid and glutathione levels during ice-bathing suggest that the intensive voluntary short-term cold exposure of winter swimming produces oxidative stress. We investigated whether the repeated oxidative stress in winter swimmers results in improved antioxidative adaptation. We obtained venous blood samples from winter swimmers and determined important components of the antioxidative defense system in the erythrocytes or blood plasma: reduced and oxidized glutathione (GSH and GSSG), and the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (Cat). The control group consisted of healthy people who had never participated in winter swimming. The baseline concentration of GSH and the activities of erythrocytic SOD and Cat, were higher in winter swimmers. We interpret this as an adaptative response to repeated oxidative stress, and postulate it as a new basic molecular mechanism of increased tolerance to environmental stress.
Article
Nine healthy males were infused with norepinephrine (o. μg/kg min) for 20 min before and after five 40-hr weeks of seminude exposure to 5 C. All infusions were given in the basal state, in a quiet room at 27 C, after a 30-min period of control measurements. Rectal temperatures and respiratory rates were unchanged either by the drug or the intervening cold exposure. The drug increased respiratory minute volumes and tidal volumes and decreased heart rates, but equally so in both experiments. Mean skin temperatures were unaffected by the drug but were significantly (P < .025) higher after cold exposure (mean 1 C). Both basal and drug-induced increase above basal of systolic and diastolic blood pressures was significantly lower (P < .025) after cold exposure. Oxygen consumption was the same in both basal periods and was unaffected by the drug before cold exposure. After cold exposure, norepinephrine produced a significant (P < .025) increase in oxygen consumption (mean 18 cc/min m ² ). These results show a changed sensitivity to norepinephrine in cold-exposed men, with a decrease in vasopressor response and the development of a calorigenic response. The data suggest that in men, norepinephrine may be a mediator of a nonshivering thermogenesis occurring with cold acclimatization. Note: (With the Assistance of Joseph C. Matone, Gerald W. Newcomb, and Wendell C. Bradford) cold exposure; catecholamines; norepinephrine calorigenesis; nonshivering thermogenesis Submitted on May 2, 1963
Article
Long-distance swimmers swam in 10–14°C water on four days. Responses in blood pressure and rectal temperature were determined every day, and hormonal responses on the third day. Swimming time lengthened with the days and diastolic blood pressure after swimming was significantly lower on the fourth day than on the first day. In rectal temperatures there were great individual variations. Noradrenaline was elevated more in the thin swimmers. A lesser rise in diastolic blood pressure and the longer duration of swimming on the fourth day may point to habituation to the cold.
Article
Metabolic responses, skin temperatures and changes in heart rate and blood pressure were measured in a control group and in “polar swimmers” after infusion of different doses of epinephrine, norepinephrine and isoprenaline. In controls the highest infusion dose of isoprenaline (0.1 μg min−1 kg−1) increased metabolic rate in normal humans by 36%, while the highest infusion doses of epinephrine and norepinephrine (0.45 μg min−1 kg−1) increased metabolic rate by 24%, only. In “polar swimmers” the epinephrine thermogenesis was potentiated significantly, reaching about 45% of the basal metabolic rate. The norepinephrine and isoprenaline thermogenesis were not different from that of the control group. It is concluded that in humans the epinephrine thermogenesis is probably located in muscles and in the white fat (Simonsen et al., 1992), and may be the principal mechanism of metabolic adaptation to cold. It was calculated that the increased capacity of epinephrine thermogenesis in cold exposed “polar swimmers” could theoretically shift the survival limit downwards to lower environmental temperatures by about 5°C.
Article
Different types of general cold adaptation have been described over the last 50 years. Metabolic adaptation (Alacaluf Indians, Arctic Indians Eskimos), insulative adaptation (coastal Aborigines of tropical northern Australia), hypothermic adaptation (bushmen of the Kalahari desert, Peruvian Indians) and insulative hypothermic adaptation (Central Australian Aborigines, nomadic Lapps, Korean and Japanese diving women). These different types of cold adaptation are related to the intensity of the cold stress and to individual factors such as diet, the level of physical fitness and body fat content. Thus, in natural environments, man develops a strategy of adaptation to cold, which takes into account environmental and individual factors. This strategy is susceptible to be modified when these conditions change. Caloric intake deficit could have been responsible for the hypothermic adaptation observed after J.-L. Etienne's journey to the North Pole. Physiological responses were adapted to maintain an acceptable level of energetic reserves with a moderate hypothermia, which was not life threatening for the climatic conditions encountered by the polar explorer.
Article
Twenty healthy male volunteers, dressed in shorts, stayed for 30 min in a room with an ambient temperature of 28 degrees C followed by a stay in a room with a temperature of 10 degrees C for 120 min. The mean skin temperature fell rapidly during the first minutes in the cold but the rectal temperature began to fall as late as at 60 min (0.1 degree C) and was 0.4 degrees C lower at the end of the cold exposure than before it. The metabolic rate, and the systolic and diastolic blood pressures, increased, and the pulse rate fell, in the cold. Serum samples were taken before moving to the cold (10 degrees C) room and after the 2-h stay and assayed for 11 hormones. There were no significant changes in the serum concentration of adrenalin, T3, T4, testosterone, TSH or LH. The serum level of noradrenaline increased from 4.5 to 6.3 nmol l-1 (P less than 0.01) and those of cortisol, GH and prolactin fell by 20, 87 and 48% (all P less than 0.01). The total serum proteins increased by 11% and free fatty acids by 28% (P less than 0.01). Our results show that the short-term exposure of adult man to low ambient temperature does not have any effect on the pituitary-thyroid and pituitary-testis axes and adrenal medulla. The increase of noradrenaline is probably due to general activation of the sympathetic nerves at low temperatures. The decreases in the serum levels of GH and prolactin reflect a true decrease in their secretions and may be mediated by inhibitory hypothalamic mechanisms.
Histochemical reactions and activities of mitochondrial enzymes in adipose tissue around the neck arteries and in pericardium were studied in men who had been outdoor workers in northern Finland. The purpose was to study the occurrence of brown fat in workers having been exposed to cool or cold ambient temperature. Indoor workers of the same age were used as controls. Histochemically, no mitochondrial enzyme reactions were seen in the adipose tissues taken from the indoor workers, whereas some outdoor workers had some multilocular adipose tissue, mostly around the neck arteries. Biochemical parameters also showed increased enzyme activities of aerobic energy metabolism in the adipose tissue of these people. The present results suggest that working in the cold can retain brown adipose tissue in “strategic” places in human adults.
Article
Ten healthy subjects who swim regularly in ice-cold water during the winter (winter swimming), were evaluated before and after this short-term whole body exposure. A drastic decrease in plasma uric acid concentration was observed during and following the exposure to the cold stimulus. We hypothesize that the uric acid decrease can be caused by its consumption after formation of oxygen radicals. In addition, the erythrocytic level of oxidized glutathione and the ratio of oxidized glutathione/total glutathione also increased following cold exposure, which supports this hypothesis. Furthermore, the baseline concentration of reduced glutathione was increased and the concentration of oxidized glutathione was decreased in the erythrocytes of winter swimmers as compared to those of nonwinter swimmers. This can be viewed as an adaptation to repeated oxidative stress, and is postulated as mechanism for body hardening. Hardening is the exposure to a natural, e.g., thermal stimulus, resulting in an increased tolerance to stress, e.g., diseases. Exposure to repeated intensive short-term cold stimuli is often applied in hydrotherapy, which is used in physical medicine for hardening.
Article
Urinary excretion of catecholamines (CA), epinephrine (E), and norepinerphrine (NE) was determined in flight cadets (n = 46) during mid-term test sorties and was compared with the measures of these variables in fighter pilots (n = 65) during tail chase sorties. Flight cadets were divided into passed and failed cadets. Fighter pilots were divided into superior, above average, and average with flying ratings of > 7, 6-7, and <6, respectively, and with flying experience of 2050 +/- 1081 h, 884 +/- 575 h, and 616 +/- 756 h, respectively. CA excretion data showed significant intra- and intergroup differences. Excretion rates for CA and NE before and after flight were significantly higher in flight cadets than in fighter pilots. After flight, all the preflight urinary variables increased significantly in passed flight cadets, while changes in failed flight cadets were not significant. In all groups of fighter pilots, preflight excretion rates for CA, E, and NE rose postflight, but the differences within the groups were not significant. The NE/E ratio decreased significantly as a function of flight adaptation. The pre- and postflight NE/E ratios were lower in fighter pilots than in flight cadets. The delta NE/E ratio decreased in fighter pilots, but increased in flight cadets. The preflight NE/E ratio was smaller for superior than for above average and average fighter pilots, and for passed than for failed flight cadets. The postflight NE/E ratio did not show any significant differences within the groups. In superior fighter pilots, the delta NE/E ratio remained relatively stable, while it was reduced in above average and average fighter pilots.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
The cytokine response after thermal stress (sauna + swimming in ice-cold water) was investigated in subjectively healthy persons. Two groups were studied at the end of the winter season: habitual and inexperienced winter swimmers. Blood was collected at rest, after a sauna bath and after a short swim in ice-cold water. Conventional methods and ELISA kits were used to determined the blood picture, serum cortisol and dehydroepiandrosterone sulphate, plasma anti-diuretic hormone (ADH) levels, and the levels of several cytokines in plasma and in the supernatants of blood cell cultures which were stimulated with lipopolysaccharide (LPS). In regular winter swimmers, the concentrations of plasma interleukin 6 (IL-6), leukocytes, and monocytes at rest were significantly higher than in inexperienced subjects. In experienced female winter swimmers, the plasma concentration of the soluble receptor for IL-6 was significantly lower than in inexperienced female swimmers. In both groups, granulocytosis, haemoconcentration and significant increases in the concentrations of ADH, cortisol and IL-6 were observed after the stimuli. However, the changes in the cortisol concentration were dramatically larger in habitual winter swimmers. A significant correlation was found between the delta values of cortisol and the basal concentrations of IL-6. In cell cultures, the LPS-induced release of IL-1beta and IL-6 was higher at rest in the inexperienced winter swimmers. This release was dramatically suppressed after exposure to the stimuli in the inexperienced winter swimmers but tended to increase in the regular winter swimmers. These stresses appear to challenge both the neuro-endocrine and the immune systems and the results indicate that adaptive mechanisms occur in habitual winter swimmers.
Article
Thermoregulation in control subjects and cold-adapted winter swimmers was examined during 1 h of cold water immersion (13 C). It was found that the thermoregulatory functions of winter swimmers differ from those of non-cold-adapted subjects. As evident from the relationship between rectal temperature and the magnitude of cold thermogenesis, in controls a significant part of cold thermogenesis during the early phase of cooling was induced by changes in peripheral temperature input, while in the late phase of cooling it was the central temperature input which was mainly engaged in induction of cold thermogenesis. In winter swimmers the magnitude of cold thermogenesis was solely related to changes in rectal temperature, indicating the predominance of the central temperature input in activation of heat production mechanisms. The thermoregulatory threshold for induction of cold thermogenesis was lowered (by 0.34 C), but the apparent hypothalamic thermosensitivity was the same as in non-cold-adapted subjects. These differences are indicative of adaptation of thermoregulatory control centres. Additionally, the activity of thermoregulatory effectors was also changed. Shivering was induced later during cooling (after 40 min) in winter swimmers than in controls, which suggests an important participation of non-shivering thermogenesis in the early thermogenic response. Winter swimmers also showed bradycardia and a greater reduction in plasma volume during cooling. The data indirectly indicate restriction of heat loss from the body. Only a non-significant increase in quantity of subcutaneous fat was observed in winter swimmers. Thus, winter swimmers were able to survive a significantly greater temperature gradient between body and environment than non-cold-adapted subjects by modifying the sensory functions of hypothalamic thermoregulatory centres to lower heat loss and produce less heat during cold exposure. Additionally, the capacity of the total cold thermogenesis due to potentiation of non-shivering heat production was also increased. Heat produced due to thermogenic action of adrenaline may represent more than a quarter of the total cold thermogenesis. In conclusion, the data suggest that winter swimmers exhibit metabolic, hypothermic and insulative types of cold adaptation.
Neuroendocrine responses of flight cadets during the midterm tests and of fighter pilots during tail chase sorties
  • Ii
  • E M Iyer
  • D I Banerjee
  • Baboons
II. Iyer EM, Banerjee DI, BabooNS. Neuroendocrine responses of flight cadets during the midterm tests and of fighter pilots during tail chase sorties. Aviat Space Environ Med. 1994; 65: 232-236.
Acute and chronic effects of winter swimming on LH
  • Jensen F Hirsch
  • N Friedel
  • K Kroger
  • B Lang
  • R Just
  • S Ulmer
  • J Schaff
  • M Ahnert
  • P Heyne
':lermanussen M, Jensen F, Hirsch N, Friedel K, Kroger B, Lang R, Just S, Ulmer J, Schaff M, Ahnert P, Heyne K. Acute and chronic effects of winter swimming on LH, FSH,