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Endocrine effects of repeated sauna bathing

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Abstract

Ten healthy male and seven female volunteers were exposed to dry heat (in a Finnish sauna 80 degrees C) 1 h twice a day for 7 days. The levels of ACTH in plasma, cortisol, TSH, thyroid hormones, testosterone, gonadotropins, prolactin and GH in serum and urinary excretion of catecholamines were determined before the experiment, and on the first, third and seventh days. Females participated only in prolactin studies. During the experiments there were no statistically significant changes in serum thyroid hormones, TSH, testosterone, FSH and LH levels. Serum cortisol and plasma ACTH decreased and urinary catecholamine increased slightly at the end of the experiment (P less than 0.05). Serum GH and prolactin in males exhibited 16- and 2.3-fold increases (P less than 0.01), respectively. In females serum prolactin rose over four-fold (P less than 0.01). The GH rise in response to hyperthermia declined after the third day but prolactin remained elevated at the end of the experiments in males. The release of prolactin in females was also high and may be associated with the transient amenorrhoea that occurred in five out of seven subjects after the experiment. The increased release of prolactin and perhaps that of GH may be associated to the heat-exposure-induced dehydration.

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... In physically active individuals, TES is especially important for the growth and maintenance of skeletal muscles, bones, and red blood cells (Zitzmann & Nieschlag, 2001). Plasma TES concentrations during the sauna bath did not change in the studies conducted by Leppäluoto et al. (1986) and Kukkonen-Harjula et al. (1989). In turn, Kukkonen-Harjula and Kauppinen (1988) demonstrated sauna-induced changes in TES secretion. ...
... The above could indicate that intermittent exposure to hot and cold stress partially stabilizes blood COR levels and alleviates stress in men who are regular sauna users. In research dedicated to thermal stress, COR levels remained unchanged in the experiments performed by Latikainen et al. (1988) and Jokinen et al. (1991); they decreased by 10%-40% in the work of Leppäluoto et al. (1986) and Kukkonen-Harjula et al. (1989), and increased 1.5-to 3-fold in the highest number of published studies (Jezova et al., 1994;Kauppinen et al., 1989;Kukkonen-Harjula et al., 1989;Pilch et al., 2003Pilch et al., , 2007Pilch et al., , 2013Vescovi et al., 1997). In the current study, COR levels decreased during repeated hot and cold treatment, which contradicts the results reported by Kauppinen et al. (1989) who observed an increase in COR concentrations during combined sauna treatment, in particular with ice-water immersion. ...
... The cited authors did not observe significant changes in PRL levels during physical stress. In most studies investigating the effects of sauna on the hormonal system, PRL levels increased 2-to 10-fold (Jezova et al., 1994;Jokinen et al., 1991;Kukkonen-Harjula et al., 1989;Latikainen et al., 1988;Leppäluoto et al., 1986;Sirviö et al., 1987Vescovi et al., 1990, 1992. The influence of thermal stress on changes in DHEA-S concentrations has not been studied to date. ...
Article
The aim of the study was to determine the effect of repeated hot thermal stress and cold water immersion on the endocrine system of young adult men with moderate and high levels of physical activity (PA). The research was conducted on 30 men aged 19–26 years (mean: 22.67 ± 2.02) who attended four sauna sessions of 12 min each (temperature: 90−91°C; relative humidity: 14–16 %). Each sauna session was followed by a 6-min cool-down break during which the participants were immersed in cold water (10−11°C) for 1 min. Testosterone (TES), cortisol (COR), dehydroepiandrosterone sulfate (DHEA-S), and prolactin (PRL) levels were measured before and after the sauna bath. The participants’ PA levels were evaluated using the International Physical Activity Questionnaire. Serum COR levels decreased significantly (p < .001) from 13.61 to 9.67 µg/ml during 72 min of sauna treatment. No significant changes (p >.05) were noted in the concentrations of the remaining hormones: TES increased from 4.04 to 4.24 ng/ml, DHEA-S decreased from 357.5 to 356.82 µg/ml, and PRL decreased from 14.50 to 13.71 ng/ml. After sauna, a greater decrease in COR concentrations was observed in males with higher baseline COR levels, whereas only a minor decrease was noted in participants with very low baseline COR values (r =−0.673, p <.001). Repeated use of Finnish sauna induces a significant decrease in COR concentrations, but does not cause significant changes in TES, DHEA-S, or PRL levels. Testosterone concentrations were higher in men characterized by higher levels of PA, both before and after the sauna bath.
... In physically active individuals, TES is especially important for the growth and maintenance of skeletal muscles, bones, and red blood cells (Zitzmann & Nieschlag, 2001). Plasma TES concentrations during the sauna bath did not change in the studies conducted by Leppäluoto et al. (1986) and Kukkonen-Harjula et al. (1989). In turn, Kukkonen-Harjula and Kauppinen (1988) demonstrated sauna-induced changes in TES secretion. ...
... The above could indicate that intermittent exposure to hot and cold stress partially stabilizes blood COR levels and alleviates stress in men who are regular sauna users. In research dedicated to thermal stress, COR levels remained unchanged in the experiments performed by Latikainen et al. (1988) and Jokinen et al. (1991); they decreased by 10%-40% in the work of Leppäluoto et al. (1986) and Kukkonen-Harjula et al. (1989), and increased 1.5-to 3-fold in the highest number of published studies (Jezova et al., 1994;Kauppinen et al., 1989;Kukkonen-Harjula et al., 1989;Pilch et al., 2003Pilch et al., , 2007Pilch et al., , 2013Vescovi et al., 1997). In the current study, COR levels decreased during repeated hot and cold treatment, which contradicts the results reported by Kauppinen et al. (1989) who observed an increase in COR concentrations during combined sauna treatment, in particular with ice-water immersion. ...
... The cited authors did not observe significant changes in PRL levels during physical stress. In most studies investigating the effects of sauna on the hormonal system, PRL levels increased 2-to 10-fold (Jezova et al., 1994;Jokinen et al., 1991;Kukkonen-Harjula et al., 1989;Latikainen et al., 1988;Leppäluoto et al., 1986;Sirviö et al., 1987Vescovi et al., 1990, 1992. The influence of thermal stress on changes in DHEA-S concentrations has not been studied to date. ...
Article
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The aim of the study was to determine the effect of repeated hot thermal stress and cold water immersion on the endocrine system of young adult men with moderate and high levels of physical activity (PA). The research was conducted on 30 men aged 19–26 years (mean: 22.67 ± 2.02) who attended four sauna sessions of 12 min each (temperature: 90−91°C; relative humidity: 14–16 %). Each sauna session was followed by a 6-min cool-down break during which the participants were immersed in cold water (10−11°C) for 1 min. Testosterone (TES), cortisol (COR), dehydroepiandrosterone sulfate (DHEA-S), and prolactin (PRL) levels were measured before and after the sauna bath. The participants’ PA levels were evaluated using the International Physical Activity Questionnaire. Serum COR levels decreased significantly ( p < .001) from 13.61 to 9.67 µg/ml during 72 min of sauna treatment. No significant changes ( p >.05) were noted in the concentrations of the remaining hormones: TES increased from 4.04 to 4.24 ng/ml, DHEA-S decreased from 357.5 to 356.82 µg/ml, and PRL decreased from 14.50 to 13.71 ng/ml. After sauna, a greater decrease in COR concentrations was observed in males with higher baseline COR levels, whereas only a minor decrease was noted in participants with very low baseline COR values ( r =−0.673, p <.001). Repeated use of Finnish sauna induces a significant decrease in COR concentrations, but does not cause significant changes in TES, DHEA-S, or PRL levels. Testosterone concentrations were higher in men characterized by higher levels of PA, both before and after the sauna bath.
... Another hormone, whose secretion is increased by thermal stress, is growth hormone (hGH). Previous papers report a large increase of circulating hGH was observed after sauna exposure (13)(14)(15)(16). These studies, however primarily used men as subjects. ...
... A statistically significant increase of hGH was observed after the first and the last sauna session. Similar changes were observed and reported by others, however, a greater increase in hGH was reported by some investigators studying men, than was seen in the women of our present experiment (14)(15)(16)25,27). Several factors cause increased secretion of hGH in a hot environment, such as: stimulation of adrenenergic system, dehydration, and increased secretion of vasopressin (13,14,28). ...
... Similar changes were observed and reported by others, however, a greater increase in hGH was reported by some investigators studying men, than was seen in the women of our present experiment (14)(15)(16)25,27). Several factors cause increased secretion of hGH in a hot environment, such as: stimulation of adrenenergic system, dehydration, and increased secretion of vasopressin (13,14,28). Additionally, a correlation between the stimulation of hGH secretion and increase of the internal temperature was observed by Christensen et al. (29). ...
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Introduction: The physiological responses to single and repeated hyperthermia exposure in men are well described in the literature, but less information is available on the effects of repeated thermal exposure in women. Aim of the study: The purpose of this study was to investigate the influence of single and repeated sauna exposure on selected endocrine responses in women. Methods: Ten healthy, eumenhorreic, female volunteers (19-21 yr old) were exposed to sauna bath seven times every second day. In all women the experiment started in the early follicular phase. Results: Body mass decreased by 0.68 kg and by 0.67 kg after the first and the last sauna respectively. Rectal temperature increased by 1.1°C and 0.8°C after the first and the last heat exposure. Plasma volume decreased by 4.6% after the first sauna, and by 6.1% after the last one. Statistically significant decrease in plasma T 3 concentration was observed after the last sauna exposure, whereas more than a threefold increase in hGH was observed after the first and more than twofold increase was noted after the last sauna. There were significant increases in ACTH and cortisol after each sauna bath, however the rise in these hormones was less pronounced after the last sauna. Conclusion: Less pronounced changes in core temperature as well as in the level of stress hormones may be the evident of adaptation to the thermal stress in women similar to that seen in men.
... They reported in the experimental group of 10 subjects the decrease in dynamic leg press 1-repetition maximum (RM) performance but no change in dynamic bench press 1RM, whereas no decrease muscular power in vertical jump. Sauna bathing has been reported to elevate serum levels of GH to 2-to 5-fold right after the sauna bath (4,18,21,22,32). Acute effects of sauna bathing (80-100°C) on serum cortisol levels are somewhat contradictory. ...
... Various cortisol responses to sauna bathing may depend on the different durations and temperatures used in these studies, and the trend is that the higher sauna humidity and temperature will lead to higher elevations in cortisol immediately after the sauna bath or after the postsauna cooling period (18,27). Nevertheless, no changes in the serum testosterone concentration have been observed after sauna bathing (18,21). ...
... Therefore, all the subjects were analyzed as one group in the GH 22kD analysis. Serum GH 22kD elevated significantly after 3 exercise loadings in MID and in all loadings including the sauna bath alone in POST, which supports the previous findings so that both the exercise (10,35) and sauna bath (18,21,22,32) can stimulate the anterior pituitary gland to secrete the GH 22kD pulse. Possible long-term effects of frequent sauna bathing on body composition, GH 22kD basal levels, and acute GH 22kD responses after the sauna may be interesting aspects to study in the future. ...
Article
Rissanen, JA, Häkkinen, A, Laukkanen, J, Kraemer, WJ, and Häkkinen, K. Acute neuromuscular and hormonal responses to different exercise loadings followed by a sauna. J Strength Cond Res XX(X): 000-000, 2019-The purpose of this study was to investigate acute responses of endurance (E + SA), strength (S + SA), and combined endurance and strength exercise (C + SA) followed by a traditional sauna bath (70˚C70˚C, 18% relative humidity) on neuromuscular performance and serum hormone concentrations. Twenty-seven recreationally physically active men who were experienced with taking a sauna participated in the study. All the subjects performed a sauna bath only (SA) first as a control measurement followed by S + SA and E + SA (paired matched randomization) and C + SA. Subjects were measured PRE (before exercise), MID (immediately after exercise and before sauna), POST (after sauna), POST30min (30 minutes after sauna), and POST24h (24 hours after PRE). Maximal isometric leg press (ILPF max) and bench press (IBPF max) forces, maximal rate of force development (RFD) and countermovement vertical jump (CMVJ), serum testosterone (TES), cortisol (COR), and 22-kD growth hormone (GH 22kD) concentrations were measured. All exercise loadings followed by a sauna decreased ILPF max (29 to 215%) and RFD (220 to 226%) in POST. ILPF max , RFD, and CMVJ remained at significantly (p # 0.05) lowered levels after S + SA in POST24h. IBPF max decreased in POST in S + SA and C + SA and remained lowered in POST24h. SA decreased ILPF max and IBPF max in POST and POST30min and remained lowered in ILPF max (24.1%) at POST24h. GH 22kD , TES, and COR elevated significantly in all loadings measured in the afternoon in MID. SA only led to an elevation (15%) in TES in POST. The strength exercise followed by a sauna was the most fatiguing protocol for the neuromuscular performance. Traditional sauna bathing itself seems to be strenuous loading, and it may not be recommended 24 hours before the next training session. A sauna bath after the loadings did not further change the hormonal responses recorded after the exercise loadings.
... Heat acclimation (HA) is a method of increasing an athlete's efficiency for training and competition activity in hot [1][2][3][4] and thermoneutral conditions [2,[5][6][7][8]. Heat acclimation is the effect of systematic, artificial exposure of the body to frequent, continuous, or intermittent heat [9], which has an impact on physiological and hematological indices of individuals and can induce numerous physiological adjustments [1,10,11], including: a reduction in resting core body temperature [10,[12][13][14], resting heart rate [6,15], an increase in cutaneous heat loss, a greater sweat rate and skin blood flow, as well as lower core temperature thresholds for activating thermoeffectors [4,16]. Moreover, heat acclimation could improve heat tolerance, maximal oxygen uptake [5,[17][18][19][20][21][22][23], ergogenic potential for endurance performance [24], energy efficiency of muscle work as well as limit excess fluid loss from the body, feelings of discomfort, and a disturbed relationship between oxygen consumption and the heart rate [4]. 2 of 21 Expansion in blood and plasma volumes is a very early change, widely observed and prominent in the HA-phenotype, irrespective of the method employed to adapt to the heat [2,12,[25][26][27][28][29][30]. ...
... Passive and active heat stress strategies and their combination are used. The passive HA strategies include resting in a heat chamber [39,40], sauna [15,[41][42][43], or hot bath [44][45][46], all of which raise and maintain a moderately high core and skin temperature [32,36]. The protocols from the mentioned studies did not include exercise but made use of different heat stimuli temperatures, durations, and methods. ...
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The influence of a series of ten sauna baths (MPHA) on thermophysiological and selected hematological responses in 14 elite cross-country skiers to a submaximal endurance exercise test performed under thermoneutral environmental conditions was studied. Thermal and physiological variables were measured before and after the exercise test, whereas selected hematological indices were studied before, immediately after, and during recovery after a run, before (T1) and after sauna baths (T2). MPHA did not influence the baseline internal, body, and skin temperatures. There was a decrease in the resting heart rate (HR: p = 0.001) and physiological strain (PSI: p = 0.052) after MPHA and a significant effect of MPHA on systolic blood pressure (p = 0.03), hematological indices, and an exercise effect but no combined effect of treatments and exercise on the tested variables. A positive correlation was reported between PSI and total protein (%ΔTP) in T2 and a negative between plasma volume (%ΔPV) and mean red cellular volume (%ΔMCV) in T1 and T2 in response to exercise and a positive one during recovery. This may suggest that MPHA has a weak influence on body temperatures but causes a moderate decrease in PSI and modifications of plasma volume restoration in response to exercise under temperate conditions in elite athletes.
... For example, Jokinen et al. [10] reported increased blood cortisol concentration as a manifestation of both the emotional stress and physical discomfort caused by the sauna environment. Other authors detected reduction of the plasma cortisol exposure to sauna condition [12,18,19]. The increased plasma GH concentration is also thought to be a reflection of a non-specific response to thermal stress and the HR [bpm] rehydration no rehydration reaction of hypothalamus to heat. ...
... As reported by Saini et al. [25], the magnitude of the exercise-induced GH response and the elevation of Tre were reduced when the subjects were rehydrated before the exercise. Leppaluoto et al. [19] found that plasma concentrations of cortisol and testosterone were insignificantly increased after the 2-h stay in a sauna. In our study, the level of T was significantly elevated at the 60 th min of the bath without the supply of drinking water and when the subjects were rehydrated the effect was detectable already at the 30 th min. ...
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The experiments were carried out in eight young males of mean age 23.1±1.4 years, mean body height 1855.0 cm, mean body mass 86.25.92 kg, and mean ‡O 2 max 4.30.92 l O 2 ·min-1. The subjects took a Finnish sauna bath twice at a week interval; the temperature of the bath was 90 o C and the relative humidity 35%. The total time of the bathing was divided into four 15-min exposures separated by 2-to 3-min breaks. On one day of the experiment the subjects received no drinking water during the bath, and on another day they were supplied with 1 l of non-carbonated mineral water of 25 o C divided into five 200-ml portions. Body mass was measured before and after the bath. Heart rate (HR), temperatures of the tympanic membrane (Tty) and forehead (Th), and blood levels of growth hormone (GH), cortisol (C), and testosterone (T) were estimated prior to entering the sauna and during the breaks. From the concentrations of testosterone and cortisol the anabolic-catabolic index (T/C) was calculated. The bath with no rehydration led to the significant reduction of the body mass approx. by 1.430.44 kg, i.e., by 1.69% of the initial mass. The bathing accompanied by rehydration resulted in an insignificant decrease in the body mass. In every case, the bath without rehydration led to the significant elevation of HR (i.e., from approx. 78 to approx. 135 bpm), while the bath with the supply of water resulted in the significantly (P<0.05) less pronounced increase in HR, i.e., to approx. 113 bpm. Tty was significantly elevated by 1.8 o C and by 1.5 o C as a result of bathing without and with the rehydration, respectively. Mean values of Th were lower in the subjects supplied with drinking water during the bath. The exposure to exogenous heat led to the significant (P<0.05) increase in GH and T and to the significant reduction in C; the latter effect was more pronounced in the rehydrated subjects. The magnitude of hormonal responses was affected by the supply of drinking water: the " peak " of GH after the sauna decreased from 6.24.92 ng/ml in the non-rehydrated subjects to 4.94.53 ng/ml in the rehydrated ones; in contrast, the testosterone level rose from 3.91.05 ng/ml in the non-rehydrated subjects to 4.70.87 ng/ml in the rehydrated ones. Finally, the sauna exposure stimulated anabolic metabolism: the T/C value increased from the initial range of 3.1-4.3 to
... Sauna bathing does not influence fertility. In men, serum concentrations of testosterone and gonadotropins do not change even after repeated sauna use (82)(83)(84)(85). Prolactin concentration increases temporarily in both men and women during sauna bathing (82)(83)(84)(85)(86)(87). ...
... In men, serum concentrations of testosterone and gonadotropins do not change even after repeated sauna use (82)(83)(84)(85). Prolactin concentration increases temporarily in both men and women during sauna bathing (82)(83)(84)(85)(86)(87). A few studies have reported decreased sperm count or decreased sperm movement after sauna bathing (88 -90). ...
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Although sauna bathing causes various acute, transient cardiovascular and hormonal changes, it is well tolerated by most healthy adults and children. Sauna bathing does not influence fertility and is safe during the uncomplicated pregnancies of healthy women. Some studies have suggested that long-term sauna bathing may help lower blood pressure in patients with hypertension and improve the left ventricular ejection fraction in patients with chronic congestive heart failure, but additional data are needed to confirm these findings. The transient improvements in pulmonary function that occur in the sauna may provide some relief to patients with asthma and chronic bronchitis. Sauna bathing may also alleviate pain and improve joint mobility in patients with rheumatic disease. Although sauna bathing does not cause drying of the skin-and may even benefit patients with psoriasis-sweating may increase itching in patients with atopic dermatitis. Contraindications to sauna bathing include unstable angina pectoris, recent myocardial infarction, and severe aortic stenosis. Sauna bathing is safe, however, for most people with coronary heart disease with stable angina pectoris or old myocardial infarction. Very few acute myocardial infarctions and sudden deaths occur in saunas, but alcohol consumption during sauna bathing increases the risk of hypotension, arrhythmia, and sudden death, and should be avoided.
... In consequence, skin temperature ranges from 40 • C during the heating phase to 33 • C during the cooling phase after immersion in cold water [19]. Other researchers found that rectal temperature increased by 1.78 • C and tympanal temperature increased by 1.33 • C in men after 30 min of sauna bathing [20]. In a study by Pilch et al. [18], a 30-min session in a dry sauna raised rectal temperature from 37.1 to 38.4 • C and tympanal temperature from 36.8 to 39.3 • C (duration of sauna: 30-40 min, temperature: 80 • C, relative humidity: 2-5%). ...
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The aim of this study was to determine the effects of thermal stress (TS) on changes in blood biochemical parameters and fluid electrolyte levels in young adult men with moderate and high levels of physical activity. Thirty men (22.67 ± 2.02 years) were exposed to four 12-min sauna sessions (temperature: 90–91 °C; relative humidity: 14–16%) with four 6-min cool-down breaks. The evaluated variables were anthropometric, physiological, and hematological characteristics. The mean values of HRavg (102.5 bpm) were within the easy effort range, whereas HRpeak (143.3 bpm) values were within the very difficult effort range. A significant increase was noted in pO2 (p < 0.001), total cholesterol (p < 0.008), HDL (p < 0.006) and LDL cholesterol (p < 0.007). Significant decreases were observed in the SBP (by 9.7 mmHg), DBP (by 6.9 mmHg) (p < 0.001), pH (p < 0.001), aHCO3- (p < 0.005), sHCO3- (p < 0.003), BE (ecf) (p < 0.022), BE (B), ctCO2 (for both p < 0.005), glucose (p < 0.001), and LA (p < 0.036). High 72-min TS did not induce significant changes in the physiological parameters of young and physically active men who regularly use the sauna, excluding significant loss of body mass. We can assume that relatively long sauna sessions do not disturb homeostasis and are safe for the health of properly prepared males.
... Female swimmers and cyclists appear to have less amenorrhea than endurance athletes (Sanborn, Albrecht, and Wagner, 1987). Amenorrhea is not specific to physical exercise, as moving to a new school in another country or repeated intensive heat exposures can also be causes, especially in young women (Leppäluoto, Huttunen, and Hirvonen, 1986). Physical exercise amenorrhea is treated with estrogen, which additionally protects from osteoporosis and stress fractures. ...
Chapter
Research on international labor migration in professional sports (e.g., Magee & Sugden, 2002) suggests that the experiences of athletes in foreign cultures are often diverse and entail numerous pressures. In order to examine such experiences in greater depth, existential phenomenological interviews (Thomas & Pollio, 2002) were conducted with ten current and former professional basketball players, ages 24 to 55, from the US. Thematic analysis of the interview transcripts produced eight major themes that clearly characterized participants' experiences: Learning the Local Mentality, Experiencing Isolation, Connecting with Others, Exploring the Physical Environment, Dealing with the Business, Adjusting to Team Resources, Managing Team Dynamics, and Playing the Game. Taken together, the results suggest that while playing overseas required participants to manage a variety of cultural and sport-related stressors, it also afforded them opportunities for personal and professional development.
... Recently, thermal therapy has been used for a number of conditions such as inflammatory bowel diseases, chronic heart failure, chronic pain, depressive state and chronic obstructive pulmonary disease [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13]. It can be classified into two types: one type involves heating the whole body or a large part of it in a sauna or warm bath. ...
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In traditional Chinese medicine, moxibustion is a local thermal therapy that is used for several conditions. Quantifying the effects of moxibustion therapy has been difficult because the treatment temperature depends on the physician's experience, and the temperature distribution in the target area is not uniform. This prospective observational study aims to quantify the effect of local thermal stimulation to the abdomen. We developed a heat transfer control device (HTCD) for local thermal stimulation. Twenty-four healthy subjects were enrolled and they underwent abdominal thermal stimulation to the para-umbilical region with the device for 20 min. Blood flow volume in the superior mesenteric artery (SMA) and brachial artery (BA), the heart rate and the blood pressure were measured at rest, 15 min after starting thermal stimulation and 10, 20, 30 and 40 min after completing thermal stimulation. Blood flow parameters were measured by high-resolution ultrasound. In the SMA, blood flow volume was significantly increased during thermal stimulation (P < .01), as well as at 10 min (P < .01) and 20 min (P < .05) after stimulation. In the BA, blood flow volume decreased at 40 min after stimulation (P < .01). In conclusion we could quantify the effect of local thermal stimulation with an HTCD and high-resolution ultrasound. Thermal stimulation of the para-umbilical region increased blood flow in the SMA 20 min after stimulation in healthy subjects.
... [7,20] Moreover, hyperthermia stimulates secretion of growth hormone and prolactin. [6,21,22] The effects of external heating on plasma levels of other hormones, e.g. cortisol, are more varied and are likely to be related to the somewhat different study design and circadian changes in plasma levels of these hormones. ...
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Acute heat loading is encountered in several everyday situations, during physical exercise or work in a hot climate are just 2 examples. Special forms of heat exposure include different types of steam baths and saunas. External heating induces changes in haemodynamics, body fluid volume and blood flow distribution, which in turn may affect the pharmacokinetics of a drug and the therapeutic response. Documentation of the effects of heat exposure on the pharmacokinetics of drugs in humans is very limited, but based on the documentation some general conclusions can be drawn. The effects of external heating on absorption and elimination of those orally administered drugs which have been studied (e.g. midazolam, ephedrine, propranolol and tetracycline), have been minor. Systemic absorption of transdermally and subcutaneously administered drugs [insulin, nitroglycerin (glyceryl trinitrate) and nicotine] is in most cases enhanced by external heating, leading to higher plasma drug concentrations. In general, pharmacokinetic interactions between heat exposure and drug therapy are rare and limited to special situations, in which local blood flow (for example, over the skin) is enhanced many-fold because of hyperthermia. When pharmacodynamics are concerned, in most cases the probability of interactions is low, but in the treatment of malignant tumours hyperthermia may potentiate cytotoxic effects of drugs without enhancement of myelosuppressive effects.
... Female swimmers and cyclists appear to have less amenorrhea than endurance athletes (Sanborn, Albrecht, and Wagner, 1987). Amenorrhea is not specific to physical exercise, as moving to a new school in another country or repeated intensive heat exposures can also be causes, especially in young women (Leppäluoto, Huttunen, and Hirvonen, 1986). Physical exercise amenorrhea is treated with estrogen, which additionally protects from osteoporosis and stress fractures. ...
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In this paper, the authors discuss the symptoms of overtraining and burnout— two syndromes in which the etiology, after the decades of research, is still poorly understood. Overtraining is caused by an imbalance between exercise and rest, and often triggered by increased neuromuscular loading. There are no reliable diagnostic tests for overtraining. The neurological mechanisms underpinning burnout are similarly not known; however, it is generally accepted that the main cause is mental overloading. Both conditions are stress-related developmental processes suggesting malfunction of adrenal cortex and hypothalamus, mainly the pituitary. The two syndromes are also related to a variety of individual, environmental, and organizational factors. Based on the first author’s extensive practical experience of working with overtrained athletes and individuals with occupational burnout, the authors draw on both literatures to offer invaluable insights into a medical assessment and treatment of athletes suffering from overtraining. Keywords: overtraining, burnout, POMS, sports medicine INTRODUCTION Overtraining is defined as an imbalance between exercise and rest, occurring when athletes are subjected to an intensive training load without adequate rest and recovery. In addition to the physical effects, the overtraining syndrome manifests in simultaneous negative changes in the athlete’s psychosocial environment. According to Budgett (1998), the overtraining syndrome is “a condition of fatigue and underperformance, often associated with frequent infections and depression which occurs following hard training and competition” (p.  Corresponding author: Harri Selänne, LIKES Research Center, Viitaniementie 15 a, Jyväskylä, 40720 Finland, Email: harri.selanne@likes.fi No part of this digital document may be reproduced, stored in a retrieval system or transmitted commercially in any form or by any means. The publisher has taken reasonable care in the preparation of this digital document, but makes no expressed or implied warranty of any kind and assumes no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of information contained herein. This digital document is sold with the clear understanding that the publisher is not engaged in rendering legal, medical or any other professional services.
... Lack of significant differences in basal values of the temperatures between follicular and luteal phase in this experiment can be explained by the likelihood of temporary disturbances in the menstrual cycle in the women studied (delayed ovulation or an anovulatory cycle) induced by repeated heat stress. Leppäluoto et al. [36] observed 2 to 5-weeks delay in menstruation in five of seven women who repeated sauna sessions for seven days. Ovulation disturbances in women who were exposed to heat stress in sauna might result from hyperprolactinaemia, which was observed in the experiment carried out by Pilch et al. [37] also reported by other authors [38]. ...
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Objective: To determine changes in lipid metabolism in young females during single and repeated bath sessions in Finnish sauna. Methods: Nine healthy non-smoking females (20-22 years) were exposed to seven 30-minute sauna baths every two days, in the morning, in temperature 91°C and humidity 15,6%. The first session was scheduled for follicular phase of the menstrual cycle, whereas the last bath occurred during luteal phase. In blood samples collected before the 1 st and the last sauna bath and immediately afterwards haematocrit (Hct), haemoglobin (Hb) and free fatty acids (FFA), triacylglycerols (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) were analyzed. The rectal and tympanic temperatures were taken by means of Ellab electrothermometer. Results: Rectal temperature was lower in the last sauna bath than in the first one, which consequently leads to body acclimation. Losses of plasma were greater during the seventh bath than during the first one. Increase in FFA concentration can be observed after a single and repeated sauna session, which may confirms the intensified lipolysis caused by elevated secretion of hormones that activate lipolytic enzymes. Conclusions: Reduction in TC and LDL-C concentrations was observed in women after 2 weeks of repeated sauna sessions. These changes can be a good prognosis in prevention of ischaemic heart disease.
... Female swimmers and cyclists appear to have less amenorrhea than endurance athletes (Sanborn, Albrecht, and Wagner, 1987). Amenorrhea is not specific to physical exercise, as moving to a new school in another country or repeated intensive heat exposures can also be causes, especially in young women (Leppäluoto, Huttunen, and Hirvonen, 1986). Physical exercise amenorrhea is treated with estrogen, which additionally protects from osteoporosis and stress fractures. ...
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In this paper, the authors discuss the symptoms of overtraining and burnout— two syndromes in which the etiology, after the decades of research, is still poorly understood. Overtraining is caused by an imbalance between exercise and rest, and often triggered by increased neuromuscular loading. There are no reliable diagnostic tests for overtraining. The neurological mechanisms underpinning burnout are similarly not known; however, it is generally accepted that the main cause is mental overloading. Both conditions are stress-related developmental processes suggesting malfunction of adrenal cortex and hypothalamus, mainly the pituitary. The two syndromes are also related to a variety of individual, environmental, and organizational factors. Based on the first author's extensive practical experience of working with overtrained athletes and individuals with occupational burnout, the authors draw on both literatures to offer invaluable insights into a medical assessment and treatment of athletes suffering from overtraining.
... The underlying mechanism through which sauna acts on AN may be suggested by previous research and observations. In healthy people, sauna research has documented the physiological effects on the hypothalamic–pituitary–adrenal axis and the sympathetic–adrenomedullary system (De Meirleir, Arentz, Hollmann, & Vanhaelst, 1985; Kauppinen, 1997; Laatikainen, Salminen, Kohvakka, & Pettersson, 1988; Lammintausta, Syvälahti, & Pekkarinen, 1976; Landsberg, Saville, & Young, 1984; Leppaäluoto et al., 1986; Vescosi et al., 1992; Vescosi and Coiro, 1993; Ježová, Juránková, Mosnárová, Kriska, & Skultétyová, 1996; Ježová, Vetnansky´,Vetnansky´, & Vigas, 1994). Additionally, changes in hormone secretion levels produced by sauna are similar to those produced by exercise, but without the associated energy cost of exercise (Fraioli et al., 1980; Grossman et al., 1984; Howlett, 1987; Kosunen & Pakarinen, 1976; Kukkonen-Harjula & Kauppinen, 1986; Vescosi et al., 1990). ...
Article
The paper addresses the absence of reports about the sauna use among the weight loss strategies of patients with anorexia nervosa (AN). Because AN entails a relentless pursuit of thinness, it might be expected that these patients would frequently resort to saunas. The paper sustains that the absence of reports should not be taken to mean that sauna use is irrelevant to AN. Support for this possibility is founded in the apparent progress shown by AN patients whose treatment consisted of different strategies of heat supply, which included a protocol of sauna sessions. First recommended by W. Gull, heat-treatment may be relevant to hyperactivity, a significant clinical characteristic in AN. This treatment was developed as an extrapolation from animal research model, where a simple manipulation of ambient temperature (AT) was found to impede and reverse excessive running in food-restricted rats. Sauna use may have been unreported either because it impedes the development of the syndrome, or its benefits have been attributed to conventional treatments. The elucidation of sauna experience among AN patients may have potential implications for the role of heat in the treatment of AN.
... [17] Koska et al [18] found that head-out water immersion at 38 to 39°C for 25 minutes resulted in a 13-fold increase in GH and a nearly 50% increase in PRL levels. Leppaluoto et al [19] found that a 2-hour dry sauna at 80°C for 7 days caused moderate decreases in serum COR and plasma ACTH levels in healthy males. In that study, there was a 16-fold increase in GH and up to a 2.3-fold increase in PRL, whereas the GH levels decreased after the 3rd day. ...
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To investigate the effects of physical agents on the levels of stress hormones in patients with osteoarthritis (OA). Transcutaneous electrical nerve stimulation, hot packs, and therapeutic ultrasound were applied to the lumbar region and knees of patients with OA. Blood samples were taken for the measurement of the serum levels of glucose, insulin (INS), growth hormone (GH), prolactin (PRL), cortisol (COR), and plasma adrenocorticotropic hormone (ACTH) immediately before and after the 1st session, to investigate the acute effects of those physical agents on the endocrine system. The hormone levels were also measured every 5 sessions in a total of 10 sessions. The treatment response was also evaluated by using the visual analogue scale (VAS), Roland Morris Disability Questionnaire (RMDQ), and Western Ontario and McMaster Universities Arthritis Index (WOMAC) throughout the therapy period. After the 1st session, there was a decrease in INS levels and a mild decrease in PRL levels (P = 0.001 and P < 0.05, respectively). Throughout the 10-session therapy period, the INS levels increased, whereas the ACTH and COR levels decreased (P < 0.05 for all). The VAS-spine, RMDQ, VAS-knee, and WOMAC scores decreased (P = 0.001 for VAS-spine and P < 0.001 for all others). A positive correlation was detected between the changes in serum COR and WOMAC-pain score (P < 0.05). Although the combination therapy caused changes in INS level accompanied with steady glucose levels, the application of physical agents did not adversely affect the hormone levels. The decrease in ACTH and COR levels may be attributed to the analgesic effect of agents and may be an indicator of patient comfort through a central action.
... However, its influence on PRL across different species is still controversial. Some studies have reported heat stress increased serum/plasma PRL concentration in human (40,41) and ruminants (42,43). Other studies have shown that heat stress did not affect PRL concentration in pigs (44,45). ...
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MicroRNAs (MiRNAs) play critical roles in the regulation of pituitary function. MiR-130a-3p has previously been found to be down-regulated in prolactinoma, but its roles in prolactin (PRL) regulation and the underlying mechanisms are still unclear. Heat stress has been shown to induce alteration of endocrine hormones and miRNAs expressions. However, there is limited information regarding the emerging roles of miRNAs in heat stress response. In this study, we transfected miR-130a-3p mimic into the pituitary adenoma cells (GH3 cells) to investigate the function of miR-130a-3p in regulating PRL. Our results showed that miR-130a-3p overexpression significantly decreased the PRL expression at both mRNA and protein levels. Subsequently, estrogen receptor α (ERα) was identified as a direct target of miR-130a-3p by bioinformatics prediction, luciferase reporter assay and western blotting assay. Furthermore, the inhibition of ERα caused by estrogen receptor antagonist significantly reduced the PRL expression. Overexpression of ERα rescued the suppressed expression of PRL caused by miR-130a-3p mimic. Besides, we also studied the effect of heat stress on PRL and miRNAs expressions. Interestingly, we found that heat stress reduced PRL and ERα expressions while it increased miR-130a-3p expression both in vitro and in vivo. Taken together, our results indicate that miR-130a-3p represses ERα by targeting its 3'UTR leading to a decrease in PRL expression, and miR-130a-3p is correlative with heat stress-induced PRL reduction, which provides a novel mechanism that miRNAs are involved in PRL regulation.
... External heat loading has previously been shown to be a potent prolactinotrophic stimulus (Mills & Robertshaw, 1981;Christensen et al. 1985;Leppaluoto et al. 1986;Brisson et al. 1991); however, there have also been reports of heat exposure having no effect on plasma prolactin Brandenberger et al. 1979). An explanation for this might be the differing degrees to which core temperature had risen from baseline, and Brisson et al. (1991) argued that a certain body temperature threshold must be reached for heat loads to induce significant changes in blood prolactin. ...
Article
The purpose of the present study was twofold: first, to determine the extent to which elevated skin temperature is responsible for the hormonal and perceptual responses to passive heating; and second, to determine to what extent face-cooling can override the effects of raised skin temperature. Sixteen recreationally active, non-heat-acclimated volunteers (12 male, 4 female; age, 29 +/- 9 years, [mean +/- S.D.]) underwent a passive heat exposure for 60 min in a sauna maintained at 58 degrees C (13% relative humidity), conditions under which sweating effectively maintains core temperature. Subjects were allocated to one of two experimental groups which were matched for sex, age, body mass index, body surface area and sweating response; one group received face cooling (FC) every 5 min, whilst the other control group (CON) received none. Mean skin temperatures were elevated by approximately 4 degrees C for the 60 min duration (CON, 36.5 +/- 0.1 degrees C; FC, 35.7 +/- 0.1 degrees C; P < 0.05) but core temperature rose by only approximately 0.25 degrees C with no difference between groups. Circulating prolactin remained stable and showed no increase for the FC group, whereas concentrations increased by 102 +/- 34% (P < 0.05) for the CON group. No differences were observed between groups for heart rate, but the sensation of heat was less (P < 0.05) with FC. We suggest that a significant component of the prolactin response to moderate passive heating is mediated by facial skin temperature, and selective cooling of the face is associated with improved perception of thermal comfort. These results indicate that the temperature of only a small part of the total skin area (approximately 10%) has a disproportionately large effect on the hormonal and perceptual responses to heat stress.
... [10] There is considerable evidence to suggest that sauna bathing can induce profound physiological effects. [4,[11][12][13][14][15][16][17] Intense short-term heat exposure elevates skin temperature and core body temperature and activates thermoregulatory pathways via the hypothalamus [18] and CNS (central nervous system) leading to activation of the autonomic nervous system. The activation of the sympathetic nervous system, hypothalamus-pituitary-adrenal hormonal axis and the renin-angiotensin-aldosterone system leads to well-documented cardiovascular effects with increased heart rate, skin blood flow, cardiac output and sweating. ...
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Abstract Introduction Sauna bathing has a long tradition in many cultures. Many health benefits are claimed by individuals and facilities promoting sauna bathing, however the medical evidence to support these claims is not well established. This paper aims to systematically review recent research on the effects of repeated dry sauna interventions on human health. Methods A systematic search was made of medical databases for studies reporting on the health effects of regular dry sauna bathing on humans from 2000 onwards. Risk of bias was assessed according to the Cochrane Collaboration guidelines. Results Forty clinical studies involving a total of 3855 participants met the inclusion criteria. Only 13 studies were randomized controlled trials and most studies were small (n<40) and investigated a wide variety of healthy and diseased populations although more than half of the studies involved populations with elevated cardiovascular risk. Reported outcome measures were heterogeneous with most studies reporting beneficial health effects. Only one small study (n=10) reported an adverse health outcome of disrupted male spermatogenesis, with all effects being reversed within 6 months of ceasing sauna activity. Conclusions Regular dry sauna bathing has potential health benefits and may be particularly beneficial for people with cardiovascular-related conditions. Regular sauna bathing is associated with psychological, physiological, and metabolic effects fitting a hormetic stress model similar to exercise that may be contributing to its clinical benefits. Although dry sauna bathing appears to be well tolerated in clinical settings, more data of higher quality is needed on the frequency and extent of adverse side effects. Further study is also needed to determine the optimal frequency and duration of distinct types of sauna bathing for targeted health effects and the specific clinical populations who are most likely to benefit.
... [58] Minerals and trace elements are excreted in sweat, [40] so for example sufferers of Wilson's disease would benefit from excretion of copper. [59] Neuroendocrine activity (release of hormones ACTH and prolactin) and women's heart rate are significantly higher than in men, [60] growth hormone increases for both sexes, [61] there is an increase in plasma catecholamine and glucagon levels as well as significant sodium depletion, [45,62] and in a study on men only, blood concentrations of beta-endorphin immunoreactivity and testosterone were also increased. [41] Sauna bathing has many mental benefits as well. ...
... There was a 31% decrease in insulin levels and a notable reduction in blood glucose levels, suggest- ing resensitization to insulin. 5 Nowadays, because of speedily changing lifestyles, lack of exercise, sedentary life systems, and stress, early onset of diabetes is common, with overweight and obesity. ...
... It is known that agents or illnesses (e.g., Cushings syndrome) that increase the release of cortisol, induce or exacerbate psychotic symptoms [23]. Indeed, several studies have shown that sauna bathing induces hormonal changes which include lowering levels of cortisol by as much as 10-40% [25,26]. ...
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Objective: Sauna bathing has been suggested to promote mental well-being and relaxation, but the evidence is uncertain with respect to mental disorders. We aimed to assess the association of frequency of sauna bathing with risk of psychosis in the Kuopio Ischemic Heart Disease prospective population-based study. Subjects and methods: Baseline sauna bathing habits were assessed in 2,138 men aged 42 - 61 years who had no history of psychotic disorders. Participants were classified into three groups based on the frequency of sauna bathing (once, 2 - 3 and 4 - 7 times per week). Results: During a median follow-up of 24.9 years, 203 psychotic disorders were recorded. A total of 537, 1,417, and 184 participants reported having a sauna bath once a week, 2 - 3 times, and 4 - 7 times per week, respectively. In Cox regression analysis adjusted for age, compared to men who had one sauna session per week, the hazard ratio (95% confidence intervals) of psychosis for 4 - 7 sauna sessions per week was 0.23 (0.09 - 0.58). In a multivariable model adjusted for several risk factors and other potential confounders, the corresponding hazard ratio was 0.21 (0.08 - 0.52). The association was similar after further adjustment for total energy intake, socioeconomic status, physical activity, and C-reactive protein 0.22 (0.09 - 0.54) and was unchanged on additional adjustment for duration of a sauna session and temperature of the sauna bath 0.23 (0.09 - 0.57). Conclusion: Our study suggests a strong inverse and independent association between frequent sauna bathing and the future risk of psychotic disorders in a general male population.
... Swimming as a leisure activity was correlated with fewer injuries, although it is unclear which factors contributed to this reduction. Regular sauna was also significantly correlated with a lower rate of injury, thereby confirming the regenerative effect on the musculoskeletal system by the supposed mechanisms of increased skin-and muscle-blood flow, faster degradation of products of metabolism and muscle as well as up-and downregulation of a multitude of genes specific to muscle hypertrophy and atrophy (Hannuksela & Ellahham, 2001;Leppäluoto et al., 1986;McGorm, Roberts, Coombes, & Peake, 2018). ...
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The aim of this study was the analysis of incidence and type of injury in German elite powerlifters. A total of n = 57 competitive athletes of the German powerlifting federation completed a retrospective survey regarding acute and overuse injuries. With 224 total injuries, a mean incidence of 1.51 per 1.000 h or 0.49 per year was calculated. Most injuries affected the lower back (20.5%), elbow (11.2%), pelvic region (10.3) and the shoulder (9.8%). Regarding the type of injury acute inflammation (25.9%), muscle strains/sprains (20.5%) and skin lesions (13%) dominated. The mean incidence significantly declined with increasing age and training experience of the athlete. Athletes using a bench press shirt and various regenerative methods like sauna or swimming also showed decreased injury rates. There was no significant correlation between body weight, height or gender and injury incidence. Compared to other sports, the incidence of injuries and overuse syndromes is still low in powerlifting. Nonetheless, appropriate strategies in training, equipment, prevention and regeneration should be employed to protect the athlete from injury.
... No differences in relevant reproductive hormone levels occurred after sauna exposure (FSH, LH, testosterone, estradiol, inhibin B, sex hormone-binding globulin), which seems to be the finding in several sauna studies [2,3]. ...
Article
Sauna bath brings about numerous acute changes in hormone levels, partly akin to other stressful situations, partly specific for sauna. Norepinephrine increases in those accustomed to sauna bath. Sweating increases the production of antidiuretic hormone, and the renin–angiotensin system becomes activated. Of the anterior pituitary hormones, growth hormone (GH) and prolactin (PRL) secretion is increased. Also β-endorphin has been frequently reported to increase, whereas the responses of antidiuretic hormone and cortisol are variable, probably depending on the type of sauna exposure. Sperm production decreases in particular in sauna-naïve men, but reduced fertility has not been associated with regular sauna habits. Minor sex differences exist, the hormonal responses being somewhat greater in women. Sauna-naïve women may experience mild disturbances in menstrual cycle, but no effects on fertility have been reported. The hormone responses are short-lived, normalizing soon after sauna exposure during the recovery. Adaptation to regular sauna use plays an important role in the responses, which attenuate upon frequent exposure.
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.
Article
Ten healthy male volunteers were exposed to the dry heat of a Finnish sauna (+80 degrees C) for 1 h twice a day for a period of 7 days. After each exposure rectal temperature rose by 0.8-1.1 degrees C and body weight dropped by 0.7-0.9 kg. The systolic blood pressure recorded 3-5 min after the sauna did not change during the experiments but the diastolic blood pressure decreased by 7-37 mmHg (P less than 0.05). The pulse rate rose from 75-80 to 106-116 beats min-1 (P less than 0.05) after the sauna. The increased responses of pulse and temperature adapted to heat exposures so that they were significantly lower after the 3rd day (rectal temperature) or after 6th day (pulse). Metabolic rate increased by 25-33% (P less than 0.01) after the first day. Serum total proteins, Hb and Htc were significantly increased on the 1st and 3rd days but not later, although the dehydration in response to sauna was unchanged as judged from the weight losses. Serum K, Na and Fe were significantly decreased on the 3rd and 7th day indicating that special attention should be given to the electrolyte balance in long-lasting intense heat exposure. No ECG changes were found in recordings taken on the 7th day.
Article
Neuroendocrine response was investigated during and after a single 20 min bath in sauna (80 degrees C) in a group of 8 healthy men and 8 healthy women. In an additional group of 8 young men, the dynamics of plasma ACTH and cortisol levels were studied during a 30 min sauna exposure (90 degrees C). This dynamic study showed a biphasic response of plasma cortisol which decreased during the initial phase of sauna bath (15 min) and increased thereafter, reaching its maximum 15 min after the end of bathing. Maximal increase in plasma ACTH levels occurred 15 min earlier. In the first sauna exposed group the increase in body temperature was the same (about 2 degrees C) in both sexes. Nevertheless, the elevation in plasma ACTH concentration was significantly more pronounced in women than in men. In the plasma collected at the end of sauna bath inside the sauna room, a significant rise in both adrenaline and noradrenaline levels was found. Though the catecholamine responses were similar in both groups, the increase in heart rate during sauna bath was significantly higher in women. Sauna-induced prolactin release was also more pronounced in women compared with men. Thus hyperthermia induced by sauna exposure resulted in a more pronounced neuroendocrine activation in women compared with men. Moreover, it is evident that repeated blood sampling is necessary to reveal the sauna-induced activation of some hormonal systems.
Article
To study the role of physical fitness and hyperthermia in inducing growth hormone (GH) and prolactin (PRL) responses to exercise in physically fit and in non-trained healthy subjects. Ten wrestlers preparing for international competition (mean age 19), and nine untrained healthy males (mean age 21), volunteered in the study. They were exposed twice to the exercise consisting of 27 min swimming, freestyle, in water of 29 or 36 degrees C, with last 3 min increased to maximal effort. Measurement of blood pressure, heart rate, sublingual temperature and sampling of blood was performed before exercise, immediately after and after a 30-min period of rest. Body temperature, heart rate, systolic blood pressure and plasma growth hormone (GH) were significantly elevated in both groups after swimming in water of either temperature (P < 0.01). The difference between GH responses to swimming in water of 29 degrees C vs 36 degrees C was significant only in non-trained subjects and was associated with the changes of body temperature. A rise in PRL concentration was found only in exercise in warmer water (P < 0.01). There were no statistical differences between athletes and controls in any response to swimming in water of the same temperature. The augmented release of GH and PRL was the result of direct stimulation by increased body temperature.
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This review focuses on the response of "stress" hormones to heat, exercise (single or repeated bouts), and combinations of these stimuli, with particular reference to their impact upon immune function. Very hot conditions induce a typical stress response, with secretion of catecholamines and cortisol. The catecholamines induce a demargination of leukocytes, and cortisol subsequently causes cells to migrate to lymphoid tissue. Sustained exercise, even in a thermally comfortable environment, induces a larger hormonal response than moderate thermal stress. With moderate exercise, increases in leukocyte numbers are related mainly to plasma norepinephrine concentrations, but with more intense exercise epinephrine concentrations assume a major importance. As exercise continues, plasma cortisol levels also rise, inducing an influx of neutrophils from bone marrow and an efflux of other leukocyte subsets. A combination of exercise and heat stress augments both hormonal and leukocyte responses. But these changes seem to be reversed if temperatures are clamped by exercising in cold water. If a second bout of exercise is performed with an inter-test interval of 30-45 min, neither hormone concentrations nor immune responses show any great cumulative effect under temperate conditions. However, in a hot environment the second exercise bout induces a larger and more persistent neutrophilia. Training influences these various responses mainly by decreasing the stress imposed when exercising at a given absolute work-rate.
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The release of brain-gut peptides during sauna bathing was studied in seven women. All women underwent a 20 min sauna bath. Their sublingual temperature rose from 36.9 +/- 0.1 degrees C to 38.6 +/- 0.2 degrees C (mean +/- SEM). A significant increase in circulating plasma vasoactive intestinal polypeptide (VIP) was observed during heat exposure, whereas plasma pancreatic polypeptide (PP), motilin and blood glucose rose and stayed significantly elevated first during the ensuing 60 min (P less than 0.05 in all cases). A similar increase in plasma insulin failed to reach statistical significance, whereas the plasma levels of somatostatin and cholecystokinin (CCK) remained unchanged. It is suggested that the plasma VIP levels are related to compensatory mechanisms during heat exposure with vasodilatation and heat loss.
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Exercise intensity powerfully influences testosterone, cortisol, and testosterone : cortisol ratio (T:C) responses to endurance exercise. Hydration state may also modulate these hormones, and therefore may alter the anabolic/catabolic balance in response to endurance exercise and training. This study examined the effect of running intensity on testosterone, cortisol, and T : C when exercise was initiated in a hypohydrated state. Nine male collegiate runners (age = 20 +/- 0 y, height = 178 +/- 2 cm, mass = 67.0 +/- 1.8 kg, body fat % = 9.8 +/- 0.7 %, V.O2max = 65.7 +/- 1.1 ml.kg (-1).min (-1)) completed four 10-min treadmill runs differing in pre-exercise hydration status (euhydrated, or hypohydrated by 5 % of body mass) and exercise intensity (70 % or 85 % V.O2max). Body mass, urine osmolality, and urine-specific gravity documented fluid balance; blood samples drawn pre-, immediately post-, and 20 min post-exercise were analyzed for testosterone, cortisol, and T : C. Except for heart rate measured during the 70 % V.O2max trials, heart rate, V.O2, and plasma lactate were similar between euhydrated and hypohydrated conditions for a given intensity, suggesting hypohydration did not measurably increase the physiological stress of the exercise bouts. Furthermore, hydration state had no measurable effect on testosterone concentrations before, during, or after exercise at either intensity. Regardless of exercise intensity, cortisol concentrations were greater during hypohydration than euhydration pre-exercise and 20 min post-exercise. Additionally, T : C was significantly lower 20 min post-exercise at 70 % V.O2max when subjects were initially hypohydrated (T : C = 0.055) versus euhydrated (T : C = 0.072). These findings suggest that depending on exercise intensity, T : C may be altered by hydration state, therefore influencing the balance between anabolism and catabolism in response to running exercise performed at typical training intensities.
Concentrations of immunoreactive beta-endorphin (ir beta-E), corticotropin, cortisol, prolactin and catecholamines in plasma were followed in 11 healthy women during and after exposure to intense heat in a Finnish sauna bath, and compared to those in a similar control situation without exposure to heat. Heat stress significantly increased prolactin and norepinephrine secretion; the percentage increases from the initial plasma concentrations varied from 113 to 1280% (mean 510%) and from 18 to 150% (mean 86%), respectively. The response of the plasma levels of epinephrine, ir beta-E, corticotropin and cortisol to heat exposure was variable. Compared to the control situation, no statistically significant effect of heat exposure on the plasma levels of these hormones was found.
Eight healthy young men were studied during three periods of heat exposure in a Finnish sauna bath: at 80 degrees C dry bulb (80 D) and 100 degrees C dry bulb (100 D) temperatures until subjective discomfort, and in 80 degrees C dry heat, becoming humid (80 DH) until subjective exhaustion. Oral temperature increased 1.1 degrees C at 80 D, 1.9 degrees C at 100 D and 3.2 degrees C at 80 DH. Heart rate increased about 60% at 80 D, 90% at 100 D and 130% at 80 DH. Plasma noradrenaline increased about 100% at 80 D, 160% at 100 D and 310% at 80 DH. Adrenaline did not change. Plasma prolactin increased 2-fold at 80 D, 7-fold at 100 D and 10-fold at 80 DH. Blood concentrations of the beta-endorphin immunoreactivity at 100 D, adrenocorticotropic hormone (ACTH) at 100 D and 80 DH, growth hormone at 100 D and testosterone at 80 DH also increased, but cortisol at 80 D and 100 D decreased. The plasma prostaglandin E2 and serum thromboxane B2 levels did not change. Patterns related to heat exposure were observed for heart rate, plasma noradrenaline, ACTH and prolactin in the three study periods.
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Exercise-induced increases in blood somatotropin (hGH) have always been considered in terms of quantity of the circulating molecules. Knowing that the hypophysis can release several GH species, we investigated the differential release in blood of total hGH (hGHT) and the main hGH variant (hGH20K) molecules in six trained male swimmers exposed to three different conditions known to favor GH release in blood: 45 min--70% maximum oxygen uptake (VO2max) bicycling and swimming, and 20 min of sauna bathing. Based on the binding specificity of hGH antibodies, hGH20K was isolated then assayed using the Nichols immunoradiometric assay system. All three experimental conditions produced significant (P less than 0.001) elevations in blood hGHT and hGH20K. In all three cases, mean blood hGH20K contribution to blood hGHT was relatively constant (11.9, SE 0.7%). Rises in rectal temperature were not statistically related to the changes in blood hGHT. This demonstration of a relatively constant elevation in hGH20K during bicycling, swimming, and sauna bathing can hardly explain the large differences in blood hGHT responses reported in literature under similar conditions.
Article
Hormonal response to Finnish sauna bath was investigated in 20 prepubertal children (age 5-10 years). Blood leukocyte count, plasma potassium, serum aldosterone, growth hormone and prolactin concentrations increased; plasma volume, plasma sodium, catecholamines, serum antidiuretic hormone, atrial natriuretic peptide (ANP), cortisol, and thyrotropin concentrations remained unchanged during sauna bath. One hour after sauna, serum thyrotropin, atrial natriuretic peptide and blood glucose concentrations decreased, whereas the rest of the hormones remained unchanged. Our results implicate that maintenance of homeothermia resulted in moderate hormonal changes in children during Finnish sauna bath which indicate similar adequate hormonal thermoregulatory adjustment as previously documented in adults.
Article
The thermal responses of serum prolactin, cortisol and plasma arginine vasopressin were studied on pregnant and non-pregnant women. Group I consisted of 15 healthy non-pregnant women, group II of 23 women 13-14 weeks pregnant and group III of 23 women 36-37 weeks pregnant. Blood samples were taken before the stress (21-23 degrees C), at the end of a 20 min stay in a heat chamber (70 degrees C, 15% relative humidity) and 20 min and 45 min after the stress (21-23 degrees C). The rectal temperature increased 0.3-0.4 degrees C. Serum concentration of prolactin increased from the pre-stress level by 82% in group I (NS), by 25% in group II (P less than 0.05) by the end of the stress but declined steadily in group III by 12% till the end of the recovery period (P less than 0.001). The cortisol concentration increased only in group II during the recovery period (54-72%, P less than 0.05). In this group the subjects who felt discomfort after the stress had higher cortisol levels already before the stress. Arginine vasopressin levels increased significantly only in group I by 17% (P less than 0.05) and there were no differences in the proportional changes between the groups. The response of prolactin to thermal stress seems to be abolished at late pregnancy while the responses of cortisol and arginine vasopressin are not influenced by pregnancy.
Article
In order to establish possible different reactions between normal subjects and cocaine addicts to short term exposure to heat, thermal, cardiovascular and pituitary hormonal responses to hyperthermia in sauna were measured in 8 male cocaine addicts (studied after 14 days of abstinence) and in 8 age and weight matched normal men. Subjects sat for 30 min in a sauna room, where the temperature was 90 C and the relative humidity 10%. Physiological and hormonal parameters were measured just before and after sauna and after 30 min of rest at normal (21 C) room temperature. Significant and comparable increments in systolic and diastolic blood pressure, pulse rate and sublingual temperature were observed in the two groups at the end of sauna. All these parameters decreased to normal values after 30 min of rest at normal room temperature. Before sauna, ACTH, cortisol and beta-endorphin levels were similar in the two groups, whereas plasma prolactin concentrations were significantly higher in cocaine addicts. All examined hormones rose significantly in the normal controls at the end of sauna. All hormones, except cortisol, returned to the basal levels after 30 min at normal room temperature. In contrast, no significant hormonal responses to hyperthermia were observed at any time point in cocaine addicts. These data do not provide evidence of alterations in the cardiovascular and thermal adaptive responses to hyperthermia in cocaine abusers. On the other hand, the results show an impairment of the ACTH/cortisol, beta-endorphin and prolactin responses to hyperthermia in cocaine addicts.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
In the present study we have examined the response of ACTH, beta-EP, PRL, GH and LH to heat and cold exposure (90° and 4°C, respectively) in eight young healthy subjects. Sauna-induced hyperthermia resulted in an increase of plasma ACTH, beta-EP, PRL and GH, but the exposure to cold did not stimulate the secretion of these hormones. This study indicates that hyperthermia represents a form of stress which can trigger a well-defined neuroendocrine response, whereas cold exposure, at least under these experimental conditions, is unable to elicit significant hormonal changes.
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Sauna use, sometimes referred to as “sauna bathing,” is characterized by short-term passive exposure to high temperatures, typically ranging from 45 °C to 100 °C (113 °F to 212 °F), depending on modality. This exposure elicits mild hyperthermia, inducing a thermoregulatory response involving neuroendocrine, cardiovascular, and cytoprotective mechanisms that work in a synergistic fashion in an attempt to maintain homeostasis. Repeated sauna use acclimates the body to heat and optimizes the body's response to future exposures, likely due to the biological phenomenon known as hormesis. In recent decades, sauna bathing has emerged as a probable means to extend healthspan, based on compelling data from observational, interventional, and mechanistic studies. Of particular interest are the findings from large, prospective, population-based cohort studies of health outcomes among sauna users that identified strong dose-dependent links between sauna use and reduced morbidity and mortality. This review presents an overview of sauna practices; elucidates the body's physiological response to heat stress and the molecular mechanisms that drive the response; enumerates the myriad health benefits associated with sauna use; and describes sauna use concerns.
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The aim of this study was to evaluate the release of PRL to sauna-induced hyperthermia in 10 chronically alcohol-addicted male subjects after a few weeks of abstinence. In contrast with normal men the alcoholic men showed higher basal levels of PRL and the exposure to hyperthermic stress did not stimulate in PRL secretion. These results indicate that chronic alcohol abuse is associated with functional pituitary alterations similar to other states of addiction.
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The aim of the present study was to compare basic physiological, biochemical, and hormonal reactions in women who prior to the study had never had a sauna and who were subjected to a single or multiple (i.e., applied repeatedly over two weeks) thermal stress in a Finnish sauna and to evaluate these reactions in relation to the duration of the stress. Twenty healthy women tested in the present investigation were divided into two groups, each group having a sauna every two days for two weeks (i.e., seven exposures in total). The subjects from the first group bathed continuously for 30 min, while those from the second group bathed for 45 min with a five-min cooling break in the middle of the bath. The temperature and relative humidity in the sauna equalled to 80°C and 5-27%, respectively. All the physiological and biochemical tests were performed on the first and 14th days of the experiment both before and after the thermal exposure. The results indicate that the exposures to thermal stress led to reduction in the body mass which was more pronounced in group 2 (p<0.005) and to elevation of the tympanal temperature (Tty) which, in both groups, was smaller after the last visit to the sauna. The first bath in the sauna stimulated the heart rate (HR) to a similar extent in both groups of the subjects but after the last bath HR was significantly lower in group 2 (p<0.005). Enhanced secretion of the stress hormones (i.e., human growth hormone [hGH], corticotropin [ACTH] and cortisol) after the last bath in the sauna was less pronounced in group 2, whereas in group 1 the rates of elevation of hGH and ACTH were higher after the last than after the first visit to the sauna. In turn, stimulation of the production of hGH following the first sauna was significantly more pronounced (p<0.005) in group 2 than in group 1. Similar statistical difference was noted between the two groups with respect to changes in the concentration of TSH. Overall, the obtained results indicate that the 30-min continuous sauna bath is a greater stress for the organism than the 45-min bath with a 5-min break for cooling. The smaller elevations in the body temperature, HR, and serum levels of hGH, ACTH, and cortisol detected after the last sauna bath in women from group 2 suggest that in these subjects adaptive changes to thermal stress were more favourable than in those from group 1.
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Reflecting the present-day increasing significance of complementary medical treatments, phytobalneotherapy with Graminis flos (hay bath), is being used ever more frequently in the areas of prevention, clinical treatment and rehabilitation, and may be regarded as a current form of treatment. Experimental and clinical studies investigating the effects of the hay bath are, however, few and far between. In a prospective cross-over study we randomized zwolf illness-free ("healthy") test subjects to two groups, each receiving one hour of treatment in either a traditional hay bath or a "hot bath" (hyperthermia), The two groups were then investigated for differences in cardiovascular parameters (blood pressure, heart rate and sublingual temperature), subjective well-being, quality of sleep, and tolerability. Twelve male test subjects having an average age of 25.2 (+/- 3.3) years were included in the study. There were no significant differences between the two groups in terms of demographic data. Nor did the objective or subjective parameters reveal any significant differences between the groups. Side effects were documented for the hay bath group. When using the hay bath, potential side effects must be taken into account. In view of the increasing use of Graminis flos in phytobalneotherapy, investigations involving large groups of patients with defined illnesses are needed in order definitively to establish the effectiveness and risks of the hay bath.
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Integrated neural and endocrine functionsNeurotransmitter roles in temperature regulation: animal researchHuman heat balance: production versus lossPassive, intense heat exposure in humansExercise-heat stress in humansFuture researchReferences
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The contribution of growth hormone (GH), released during acute and repeated stressful situations, to the development of stress-related disorders is often neglected. We have hypothesized that the modulation of the GH response to sequential stress exposure in humans depends mainly on the nature of the stressor. To test this hypothesis, we compared GH responses to different stressful situations, namely aerobic exercise, hypoglycemia and hyperthermia, which were applied in two sequential sessions separated by 80-150 min. In addition, administration of the dopaminergic drug apomorphine was used as a pharmacological stimulus. GH responses to submaximal exercise (bicycle ergometer, increasing work loads of 1.5, 2.0 and 2.5 W/kg, total duration 20 min) and hyperthermia in a sauna (80 degrees C, 30 min) were prevented when preceded by the same stress stimulus. Hypoglycemia induced by insulin (0.1 IU/kg intravenously) resulted in a significant GH response also during the second of the two consecutive insulin tests, though the response was reduced. Administration of apomorphine (0.75 mg subcutaneously) or insulin prevented the increase in GH release in response to a sequential bolus of apomorphine, while hypoglycemia induced a significant elevation in GH levels even if applied after a previous treatment with apomorphine. In conclusion, the feedback inhibition of the GH response to a sequential stress stimulus depends on the stimulus used. Unlike in the case of exercise and hyperthermia, mechanisms involved in the stress response to hypoglycemia appear to overcome the usual feedback mechanisms and to re-induce the GH response when applied after another stimulus.
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The advent of the tranquilizers has reawakened interest in the role of the hypothalamus and diencephalic centers in behavior,1 which the evidence adduced by clinicians and neurophysiologists over many years had linked with affective disturbances. However, more than a decade ago Alpers2 reiterated Bard's conclusion3 that the expression rather than the cause of rage in animals was dependent upon diencephalic mechanisms. Nevertheless, Hoskins, in pointing to the many disturbances of homeostasis found in schizophrenia, repeated Ranson's belief that the solution to this disease might be found in the hypothalamus.4 In recent years Funkenstein and his co-workers5 reported that a prolonged hypotensive response to methacholine was linked with good outcome following electroconvulsive therapy. Gellhorn interpreted such vascular responses as indicative of the degree of central sympathetic excitability and suggested that methacholine might prove to be a sensitive indicator of such central, and especially hypothalamic, responsivity.6 Although
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Plasma renin activity (PRA), angiotensin II, and aldosterone levels, arterial blood pressure, and heart rate of six male students were investigated during and after heat stress in a sauna bath. Increased PRA, angiotensin II, and aldosterone levels were found both during and after sauna. The greatest mean increases in PRA (94.9 +/- 10.4% SE, P less than 0.005) and angiotensin II (196 +/- 54.7% SE, P less than 0.02) were observed at the end of the heat stress (at 20 min), and that in plasma aldosterone (505 +/- 209% SE, P less than 0.02) 30 min after the sauna. The heart rate roughly doubled during the heat stress and there was a transient increase followed by a decrease in systolic blood pressure and a decrease in diastolic blood pressure. This study demonstrates that intense heat stress can cause remarkable changes in the three main components of the renin-angiotensin-aldosterone system.
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Plasma renin activity (PRA), renin concentration (PRC), angiotensin II and urinary aldosterone of four male athletes were investigated before and after a running exercise of 3 X 300 m. After the exercise, there were marked increases in all these parameters. The maximal increases (of the means and the ranges), found in the samples taken 30 min after the exercise, were: 108% (27-230%, P less than 0.05) in PRA, 490% (240-800%, P less than 0.01) in PRC, 830% (400-1,970%, P less than 0.025) in plasma angiotensin II and 1,600% (160-3,920%, P less than 0.02) in plasma aldosterone. The increase in the urinary excretion of aldosterone was 120% (42-180%, P less than 0.025). This study demonstrates that intense physical exercise may cause marked changes in all the three main components of the renin-angiotensin-aldosterone system. The significance of these changes for the physiological function of the human organism in physical stress needs further investigation.
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Ten healthy male volunteers were exposed to the dry heat of a Finnish sauna (+80 degrees C) for 1 h twice a day for a period of 7 days. After each exposure rectal temperature rose by 0.8-1.1 degrees C and body weight dropped by 0.7-0.9 kg. The systolic blood pressure recorded 3-5 min after the sauna did not change during the experiments but the diastolic blood pressure decreased by 7-37 mmHg (P less than 0.05). The pulse rate rose from 75-80 to 106-116 beats min-1 (P less than 0.05) after the sauna. The increased responses of pulse and temperature adapted to heat exposures so that they were significantly lower after the 3rd day (rectal temperature) or after 6th day (pulse). Metabolic rate increased by 25-33% (P less than 0.01) after the first day. Serum total proteins, Hb and Htc were significantly increased on the 1st and 3rd days but not later, although the dehydration in response to sauna was unchanged as judged from the weight losses. Serum K, Na and Fe were significantly decreased on the 3rd and 7th day indicating that special attention should be given to the electrolyte balance in long-lasting intense heat exposure. No ECG changes were found in recordings taken on the 7th day.
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To study the effect of changing serum osmolality on serum prolactin concentration 11 volunteers were given oral and intravenous hypotonic and hypertonic fluids. Mean serum prolactin fell to 10.5 percent of baseline after oral water loading and to 15 percent of baseline after intravenous hypotonic saline infusion. Conversely, mean prolactin rose to 417 percent of baseline after intravenous hypertonic saline administration. The correlation coefficient of simultaneously determined serum prolactin and osmolality was highly significant (P .001). Isoosmolar changes in extracellular fluid volume did not consistently affect the concentration of prolactin in the serum. Thus, prolactin may be involved in the physiologic regulation of osmolar balance and the kidney may be an important farget organ for prolaction.
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Laisi, U., S. Leisti, J. Leppäluoto, J. Lumio, J. Partanenand P. Virkkunen. Growth hormone and Cortisol secretion in man. Acta physiol. scand. 1973. 89. 192–197.In 4 healthy resting males blood was collected through indwelled catheters at 1–3 min intervals and EEG recorded in a sound-shielded anechoic environment for 30 min (expt. 1). The iminunorcactive plasma growth hormone was at high concentration (10–33 ng/ml) and was secreted in 3 significant bursts in one subject, but was low (0–4 ng/ml) in 3 other subjects. The plasma Cortisol, measured by a fluorometric method, was at low and constant level (mean ±S.D. = 8.9±1.5 μg/100 ml). The EEG vigilance fluctuated between wakefulness and real sleep. The plasma growth hormone concentration tended to be high at wakeful stages and low at sleep stages. There was no correlation between vigilance and plasma Cortisol level. In the middle of the following experiment (expt. 2) a painful faradic current was applied to the forearm for 10 s and blood was collected as in expt. 1. The plasma Cortisol level before the painful stimulus was significantly increased (12.3±4.6 /yg/100 nil) and did not change after the stimulus, in spite of the clear increase of vigilance. The high prc-stimulus level of plasma Cortisol is evidently due to anticipatory mechanisms. We conclude that growth hormone is secreted in bursts which may last as short as 5 min and that the increase of vigilance could trigger the secretion of growth hormone but not that of Cortisol.
Strong heat exposure and adenohypophyseal hormone secretion in man Some cardiovas-cular and metabolic effects of repeated sauna bathing
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LEPPALUOTO, J., RANTA, T., LAN, U., PARTANEN, J., VIRKKUNEN, P. & LYBECK, H. 1975. Strong heat exposure and adenohypophyseal hormone secretion in man. Horm Met Res 7, 4 3 ~ 4 0. LEPPALUOTO, J., TUOMINEN, M., VMNANEN, A., KARPAKKA, J. & VUORI, J. 1986. Some cardiovas-cular and metabolic effects of repeated sauna bathing. Acta Physiol Scand 128, 77-81.
Effect of Finnish bath (sauna) on the urinary excretion of noradrenaline, and adrenaline and 3-methoxy-qhydroxymandelic acid Biogenic monamines and cold exposure tolerance in guinea-pigs. Acta Universit-atis Ouluensis. Series A Scientiae rerum naturalium
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HUIKKO, M., JOUPPILA, P. & KXRKI, N. 1976. Effect of Finnish bath (sauna) on the urinary excretion of noradrenaline, and adrenaline and 3-methoxy-qhydroxymandelic acid. Acta Physiol Scand 68, HUTTUNEN, P. 1979. Biogenic monamines and cold exposure tolerance in guinea-pigs. Acta Universit-atis Ouluensis. Series A Scientiae rerum naturalium. Biochemica no. 24. KOSUNEN, K. J., PAKARINEN, A. J., KUOPPASALMI, K. & ADLERCREUTZ, H. 1976. Plasma renin activity, angiotensin 11, and aldosterone during intense heat stress. 3 Appl Physiol41, 26-29.
Biogenic monamines and cold exposure tolerance in guinea-pigs. Acta Universit-atis Ouluensis. Series A Scientiae rerum naturalium.
  • Huttunen
Plasma renin activity, angiotensin II, and aldosterone during intense heat stress.
  • Kosunen