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Ten-day endurance training attenuates the hyperosmotic suppression of cutaneous vasodilation during exercise but not sweating.
J Appl Physiol (1985). 2005 Jul; 99(1):237-43.JA

Abstract

It is well known that hyperosmolality suppresses thermoregulatory responses and that plasma osmolality (P(osmol)) increases with exercise intensity. We examined whether the decreased esophageal temperature thresholds for cutaneous vasodilation (TH(FVC)) and sweating (TH(SR)) after 10-day endurance training (ET) are caused by either attenuated increase in P(osmol) at a given exercise intensity or blunted sensitivity of hyperosmotic suppression. Nine young male volunteers exercised on a cycle ergometer at 60% peak oxygen consumption rate (V(O2 peak)) for 1 h/day for 10 days at 30 degrees C. Before and after ET, thermoregulatory responses were measured during 20-min exercise at pretraining 70% V(O2 peak) in the same environment as during ET under isoosmotic or hyperosmotic conditions. Hyperosmolality by approximately 10 mosmol/kgH2O was attained by acute hypertonic saline infusion. After ET, V(O2 peak) and blood volume (BV) both increased by approximately 4% (P < 0.05), followed by a decrease in TH(FVC) (P < 0.05) but not by that in TH(SR). Although there was no significant decrease in P(osmol) at the thresholds after ET, the sensitivity of increase in TH(FVC) at a given increase in P(osmol) [deltaTH(FVC)/deltaP(osmol), degrees C x (mosmol/kgH2O)(-1)], determined by hypertonic infusion, was reduced to 0.021 +/- 0.005 from 0.039 +/- 0.004 before ET (P < 0.05). The individual reductions in deltaTH(FVC)/deltaP(osmol) after ET were highly correlated with their increases in BV around TH(FVC) (r = -0.89, P < 0.005). In contrast, there was no alteration in the sensitivity of the hyperosmotic suppression of sweating after ET. Thus the downward shift of TH(FVC) after ET was partially explained by the blunted sensitivity to hyperosmolality, which occurred in proportion to the increase in BV.

Authors+Show Affiliations

Dept. of Sports Medical Sciences, Shinshu Univ. Graduate School of Medicine, Matsumoto, Japan.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

15761088

Citation

Ichinose, Takashi, et al. "Ten-day Endurance Training Attenuates the Hyperosmotic Suppression of Cutaneous Vasodilation During Exercise but Not Sweating." Journal of Applied Physiology (Bethesda, Md. : 1985), vol. 99, no. 1, 2005, pp. 237-43.
Ichinose T, Okazaki K, Masuki S, et al. Ten-day endurance training attenuates the hyperosmotic suppression of cutaneous vasodilation during exercise but not sweating. J Appl Physiol. 2005;99(1):237-43.
Ichinose, T., Okazaki, K., Masuki, S., Mitono, H., Chen, M., Endoh, H., & Nose, H. (2005). Ten-day endurance training attenuates the hyperosmotic suppression of cutaneous vasodilation during exercise but not sweating. Journal of Applied Physiology (Bethesda, Md. : 1985), 99(1), 237-43.
Ichinose T, et al. Ten-day Endurance Training Attenuates the Hyperosmotic Suppression of Cutaneous Vasodilation During Exercise but Not Sweating. J Appl Physiol. 2005;99(1):237-43. PubMed PMID: 15761088.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Ten-day endurance training attenuates the hyperosmotic suppression of cutaneous vasodilation during exercise but not sweating. AU - Ichinose,Takashi, AU - Okazaki,Kazunobu, AU - Masuki,Shizue, AU - Mitono,Hiroyuki, AU - Chen,Mian, AU - Endoh,Hiroshi, AU - Nose,Hiroshi, Y1 - 2005/03/10/ PY - 2005/3/12/pubmed PY - 2005/9/20/medline PY - 2005/3/12/entrez SP - 237 EP - 43 JF - Journal of applied physiology (Bethesda, Md. : 1985) JO - J. Appl. Physiol. VL - 99 IS - 1 N2 - It is well known that hyperosmolality suppresses thermoregulatory responses and that plasma osmolality (P(osmol)) increases with exercise intensity. We examined whether the decreased esophageal temperature thresholds for cutaneous vasodilation (TH(FVC)) and sweating (TH(SR)) after 10-day endurance training (ET) are caused by either attenuated increase in P(osmol) at a given exercise intensity or blunted sensitivity of hyperosmotic suppression. Nine young male volunteers exercised on a cycle ergometer at 60% peak oxygen consumption rate (V(O2 peak)) for 1 h/day for 10 days at 30 degrees C. Before and after ET, thermoregulatory responses were measured during 20-min exercise at pretraining 70% V(O2 peak) in the same environment as during ET under isoosmotic or hyperosmotic conditions. Hyperosmolality by approximately 10 mosmol/kgH2O was attained by acute hypertonic saline infusion. After ET, V(O2 peak) and blood volume (BV) both increased by approximately 4% (P < 0.05), followed by a decrease in TH(FVC) (P < 0.05) but not by that in TH(SR). Although there was no significant decrease in P(osmol) at the thresholds after ET, the sensitivity of increase in TH(FVC) at a given increase in P(osmol) [deltaTH(FVC)/deltaP(osmol), degrees C x (mosmol/kgH2O)(-1)], determined by hypertonic infusion, was reduced to 0.021 +/- 0.005 from 0.039 +/- 0.004 before ET (P < 0.05). The individual reductions in deltaTH(FVC)/deltaP(osmol) after ET were highly correlated with their increases in BV around TH(FVC) (r = -0.89, P < 0.005). In contrast, there was no alteration in the sensitivity of the hyperosmotic suppression of sweating after ET. Thus the downward shift of TH(FVC) after ET was partially explained by the blunted sensitivity to hyperosmolality, which occurred in proportion to the increase in BV. SN - 8750-7587 UR - https://www.unboundmedicine.com/medline/citation/15761088/Ten_day_endurance_training_attenuates_the_hyperosmotic_suppression_of_cutaneous_vasodilation_during_exercise_but_not_sweating_ L2 - http://www.physiology.org/doi/full/10.1152/japplphysiol.00813.2004?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -