Effect of voluntary dehydration on thermoregulatory responses to heat in men and women

Grucza, Ryszard; Lecroart, Jean Louis; Carette, G; Hauser, Jean Jacques; Houdas, Y

doi:10.1007/bf00690899

Cited by 10 publications

(5 citation statements)

References 21 publications

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“…Based on the literature, some authors suggest that the sweating rate is higher in male compared to female athletes [55,56]. Nevertheless, others proposed that women take more time than men to begin sweating [57]. With this in mind, the influence of hydration status on physiological stress induced by exercise is an important issue to be investigated in future projects.…”

Section: Discussionmentioning

confidence: 99%

Sex Differences in Physiological Stress Induced by a Long-Lasting Adventure Race: A Prospective Observational Analytical Study

Silva

Vilaça

Guerra

et al. 2019

Sportverletz Sportschaden

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Background In order to provide additional information on the behaviour of biochemical parameters related to stress responses to a specific long-term competition, we aimed to compare the stressful effects of a long-lasting competition on physiological variables in men and women. Methods This is a prospective observational analytical study. Twenty-five professional athletes, 15 men and 10 women, travelled 460 km for 4 days in an international edition of the Ecomotion/Pro AR World. Results After the competition, we detected an increase in α-amylase and cortisol levels and a decrease in salivary immunoglobulin A (lgA) levels. The relative percentage changes in α-amylase, IgA and cortisol levels were significantly higher in women than in men, whereas women had lower relative percentage changes in glucose and lactate levels compared with men. There was a decrease in lymphocyte, eosinophil and monocyte counts, with relative percentage decreases in lymphocytes and monocytes being significantly higher in female athletes than in males. There were increases in the serum activities of total creatine kinase (CK), the creatine kinase myocardial isoform (CKMB), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) at the end of the test, with significantly higher elevations of total CK, CKMB and LDH in men and ALT in women. Conclusion Long-lasting competition induced stress, muscle damage, anaemia and changes in the immune system. Women had more intense responses of cortisol and leukocytes.

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Section: Discussionmentioning

confidence: 99%

Sex Differences in Physiological Stress Induced by a Long-Lasting Adventure Race: A Prospective Observational Analytical Study

Silva

Vilaça

Guerra

et al. 2019

Sportverletz Sportschaden

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“…There are also some differences in thermoregulatory mechanisms in men and women, e.g. different dynamics of sweating depending on the phase of the menstrual cycle, which may be responsible for smaller body loss during body heating in women than in men [ 6 , 24 , 25 ]. The average losses of body mass for men were 0.72 kg in the dry sauna and 0.36 in the wet sauna.…”

Section: Discussionmentioning

confidence: 99%

“…High humidity of the skin slows down the speed of excretion and evaporation of sweat. In the wet sauna there is high moistness of the skin as well as droplet loss of sweat, which does not lower the temperature of the organism [ 6 , 7 ]. When the exposure to heat is extended even the most efficient mechanisms cannot stop the accumulation of heat in the organism.…”

Section: Discussionmentioning

confidence: 99%

Comparison of Physiological Reactions and Physiological Strain in Healthy Men Under Heat Stress in Dry and Steam Heat Saunas

Pilch¹,

Szyguła²,

Pałka³

et al. 2014

Biol Sport

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The aim of the paper was to follow up major physiological reactions, provoked by heat stress during dry and wet sauna baths. A physical strain index and subjective estimation of heat comfort of subjects who had not taken sauna baths before was also evaluated. Ten healthy males aged 25-28 underwent a dry sauna bath and then after a one-month break they underwent a steam sauna bath. Each time, they entered the sauna chamber 3 times for 15 minutes with five-minute breaks. During breaks they cooled their bodies with a cold shower and then rested in a sitting position. Before and after the baths, body mass and blood pressure were measured. Rectal temperature and heart rate were monitored during the baths. The physiological strain index (PSI) and cumulative heat strain index (CHSI) were calculated. Subjects assessed heat comfort by Bedford's scale. Greater body mass losses were observed after the dry sauna bath compared to the wet sauna (-0.72 vs. -0.36 kg respectively). However, larger increases in rectal temperature and heart rate were observed during the wet sauna bath (38.8% and 21.2% respectively). Both types of sauna baths caused elevation of systolic blood pressure, but changes were greater after the dry one. Diastolic pressure was reduced similarly. Subjective feelings of heat comfort as well as PSI (4.83 ± 0.29 vs. 5.7 ± 0.28) and CHSI (76.3 ± 18.4 vs. 144.6 ± 21.7) were greater during the wet sauna bath. It can be concluded that due to high humidity and reduction of thermoregulation mechanisms, the wet sauna is more stressful for the organism than the dry sauna, where the temperature is higher with low humidity. Both observed indexes (PSI and CHSI) could be appropriate for objective assessment of heat strain during passive heating of the organism.

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“…Similar to the effect of hypovolemia, dehydration also attenuates the sweating response (Ekblom et al 1970;Candas et al 1986;Grucza et al 1987). It is the increased plasma osmolality, associated with dehydration, that is sensed by hypothalamic osmosensitive neurons (Silva and Boulant 1984), that in turn modulate the thermoregulatory responses (Baker and Doris 1982 a, b).…”

Section: Introductionmentioning

confidence: 95%

Human thermoregulatory function during exercise and immersion after 35 days of horizontal bed-rest and recovery

et al. 2005

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The present study evaluated the effect of 35 days of experimental horizontal bed-rest on exercise and immersion thermoregulatory function. Fifteen healthy male volunteers were assigned to either a Control (n = 5) or Bed-rest (n = 10) group. Thermoregulatory function was evaluated during a 30-min bout of submaximal exercise on a cycle ergometer, followed immediately by a 100-min immersion in 28 degrees C water. For the Bed-rest group, exercise and immersion thermoregulatory responses observed post-bed-rest were compared with those after a 5 week supervised active recovery period. In both trials, the absolute work load during the exercise portion of the test was identical. During the exercise and immersion, we recorded skin temperature, rectal temperature, the difference in temperature between the forearm and third digit of the right hand (DeltaT(forearm-fingertip))--an index of skin blood flow, sweating rate from the forehead, oxygen uptake and heart rate at minute intervals. Subjects provided ratings of temperature perception and thermal comfort at 5-min intervals. Exercise thermoregulatory responses after bed-rest and recovery were similar. Subjective ratings of temperature perception and thermal comfort during immersion indicated that subjects perceived similar combinations of Tsk and Tre to be warmer and thermally less uncomfortable after bed-rest. The average (SD) exercise-induced increase in Tre relative to resting values was not significantly different between the Post-bed-rest (0.4 (0.2) degrees C) and Recovery (0.5 (0.2) degrees C) trials. During the post-exercise immersion, the decrease in Tre, relative to resting values, was significantly (P < 0.05) greater in the Post-bed-rest trial (0.9 (0.5) degrees C) than after recovery (0.4 (0.3) degrees C). DeltaT(forearm-fingertip) was 5.2 (0.9) degrees C and 5.8 (1.0) degrees C at the end of the post-bed-rest and recovery immersions, respectively. The gain of the shivering response (increase in VO(2) relative to the decrease in Tre; VO(2)/Tre) was 1.19 l min(-1) degrees C(-1) in the Recovery trial, and was significantly attenuated to 0.51 l min(-1) degrees C(-1) in the Post-bed-rest trial. The greater cooling rate observed in the post-bed-rest trial is attributed to the greater heat loss and reduced heat production. The former is the result of attenuated cold-induced vasoconstriction and enhanced sweating rate, and the latter a result of a lower shivering VO(2) response.

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Effect of voluntary dehydration on thermoregulatory responses to heat in men and women

Cited by 10 publications

References 21 publications

Sex Differences in Physiological Stress Induced by a Long-Lasting Adventure Race: A Prospective Observational Analytical Study

Sex Differences in Physiological Stress Induced by a Long-Lasting Adventure Race: A Prospective Observational Analytical Study

Comparison of Physiological Reactions and Physiological Strain in Healthy Men Under Heat Stress in Dry and Steam Heat Saunas

Human thermoregulatory function during exercise and immersion after 35 days of horizontal bed-rest and recovery

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