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The effect of voluntary hypocapnic hyperventilation on thermoregulatory responses in exercising humans
Author(s) -
Fujii Naoto,
Honda Yasushi,
Komura Ken,
Tsuji Bun,
Sugihara Akira,
Watanabe Kazuhito,
Kondo Narihiko,
Nishiyasu Takeshi
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1079.14
Subject(s) - forearm , forehead , hyperventilation , medicine , sweat , frontalis muscle , anesthesia , heart rate , breathing , blood pressure , surgery
We tested the hypothesis that voluntary hypocapnic hyperventilation (VHH) attenuates thermoregulatory responses in exercising humans. 10 healthy active males performed cycling exercise at 120W (30°C, 50%RH) during 1) spontaneous breathing, 2) eucapnic voluntary hyperventilation, and 3) VHH. Cutaneous vascular conductance was evaluated as cutaneous red blood cell flux measured by laser‐Doppler flowmeter/mean arterial blood pressure at forearm (CVC forearm ) and forehead (CVC forehead ). Forearm sweat rate was measured by ventilated capsule method. Our results indicated that esophageal temperature (Tes) threshold for increases in CVC forearm and CVC forehead was significantly or tended to be higher, while slope relating Tes with CVC forearm was significantly or tended to be lower in VHH than in the other two conditions. Neither Tes threshold nor slope for sweat rate was different among conditions. These results suggest that in exercising humans, although VHH does not affect sweat response, it attenuates cutaneous vasodilation response, and this attenuation is greater for forearm than forehead skin. This study was supported by grants from the Ministry of Education, Science, and Culture of Japan. N. Fujii is the recipient of a research fellowship for young scientists from Japan Society of the Promotion of Science.