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Mild hypohydration induced by exercise in the heat attenuates autonomic thermoregulatory responses to the heat, but not thermal pleasantness in humans.
Physiol Behav. 2010 Jun 16; 100(4):340-5.PB

Abstract

Hypohydration caused by exercise in the heat attenuates autonomic thermoregulation such as sweating and skin blood flow in humans. In contrast, it remains unknown if behavioral thermoregulation is modulated during hypohydration. We assume that thermal unpleasantness could drive the behavioral response, and would also be modulated during hypohydration. Nine healthy young men participated in the present study. Body and skin temperatures were monitored. Ratings of thermal sensation and pleasantness were conducted. After approximately 45 min rest at 27 degrees C, they performed 50-min cycling exercise, which was at the level of 40% of heart rate range at 35 degrees C (hypohydration trial) or at the level of 10% of heart rate range at 23 degrees C (control trial), respectively. Subjects returned to the rest at 27 degrees C, and the ambient temperature was then changed from 22 to 38 degrees C. Body weight decreased by 0.9+/-0.1% immediately after exercise in the hypohydration trial and 0.3+/-0.1% in the control trial. In the cold, no significant difference in thermal sensation or pleasantness was observed between trials. There was no significant difference in thermal pleasantness between trials in the heat, although thermal sensation in the heat (32.5-36 degrees C) was significantly lower in the hypohydration trial than in the control trial. In addition, laser Doppler flow of the skin and sweat rate were attenuated in the heat in the hypohydration trial. These results may indicate that mild hypohydration after exercise in the heat has no influence on behavioral responses to the heat.

Authors+Show Affiliations

Laboratory of Integrative Physiology, Health and Welfare, Faculty of Human Sciences, Waseda University, Tokorozawa, Saitama, Japan.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

20298707

Citation

Tokizawa, Ken, et al. "Mild Hypohydration Induced By Exercise in the Heat Attenuates Autonomic Thermoregulatory Responses to the Heat, but Not Thermal Pleasantness in Humans." Physiology & Behavior, vol. 100, no. 4, 2010, pp. 340-5.
Tokizawa K, Yasuhara S, Nakamura M, et al. Mild hypohydration induced by exercise in the heat attenuates autonomic thermoregulatory responses to the heat, but not thermal pleasantness in humans. Physiol Behav. 2010;100(4):340-5.
Tokizawa, K., Yasuhara, S., Nakamura, M., Uchida, Y., Crawshaw, L. I., & Nagashima, K. (2010). Mild hypohydration induced by exercise in the heat attenuates autonomic thermoregulatory responses to the heat, but not thermal pleasantness in humans. Physiology & Behavior, 100(4), 340-5. https://doi.org/10.1016/j.physbeh.2010.03.008
Tokizawa K, et al. Mild Hypohydration Induced By Exercise in the Heat Attenuates Autonomic Thermoregulatory Responses to the Heat, but Not Thermal Pleasantness in Humans. Physiol Behav. 2010 Jun 16;100(4):340-5. PubMed PMID: 20298707.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Mild hypohydration induced by exercise in the heat attenuates autonomic thermoregulatory responses to the heat, but not thermal pleasantness in humans. AU - Tokizawa,Ken, AU - Yasuhara,Saki, AU - Nakamura,Mayumi, AU - Uchida,Yuki, AU - Crawshaw,Larry I, AU - Nagashima,Kei, Y1 - 2010/03/15/ PY - 2009/09/14/received PY - 2010/03/08/revised PY - 2010/03/09/accepted PY - 2010/3/20/entrez PY - 2010/3/20/pubmed PY - 2010/9/24/medline SP - 340 EP - 5 JF - Physiology & behavior JO - Physiol Behav VL - 100 IS - 4 N2 - Hypohydration caused by exercise in the heat attenuates autonomic thermoregulation such as sweating and skin blood flow in humans. In contrast, it remains unknown if behavioral thermoregulation is modulated during hypohydration. We assume that thermal unpleasantness could drive the behavioral response, and would also be modulated during hypohydration. Nine healthy young men participated in the present study. Body and skin temperatures were monitored. Ratings of thermal sensation and pleasantness were conducted. After approximately 45 min rest at 27 degrees C, they performed 50-min cycling exercise, which was at the level of 40% of heart rate range at 35 degrees C (hypohydration trial) or at the level of 10% of heart rate range at 23 degrees C (control trial), respectively. Subjects returned to the rest at 27 degrees C, and the ambient temperature was then changed from 22 to 38 degrees C. Body weight decreased by 0.9+/-0.1% immediately after exercise in the hypohydration trial and 0.3+/-0.1% in the control trial. In the cold, no significant difference in thermal sensation or pleasantness was observed between trials. There was no significant difference in thermal pleasantness between trials in the heat, although thermal sensation in the heat (32.5-36 degrees C) was significantly lower in the hypohydration trial than in the control trial. In addition, laser Doppler flow of the skin and sweat rate were attenuated in the heat in the hypohydration trial. These results may indicate that mild hypohydration after exercise in the heat has no influence on behavioral responses to the heat. SN - 1873-507X UR - https://www.unboundmedicine.com/medline/citation/20298707/Mild_hypohydration_induced_by_exercise_in_the_heat_attenuates_autonomic_thermoregulatory_responses_to_the_heat_but_not_thermal_pleasantness_in_humans_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0031-9384(10)00114-9 DB - PRIME DP - Unbound Medicine ER -