| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Department of Physiology and 2 College of Medical Technology, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto 602 - 0841, Japan
Heat acclimatization
improves thermoregulatory responses to heat stress and decreases sweat
sodium concentration ([Na+]sweat). The
reduced [Na+]sweat results in a larger
increase in plasma osmolality (Posmol) at a given amount of
sweat output. The increase in Posmol inhibits thermoregulatory responses to increased body core temperature. Therefore, we hypothesized that the inhibitory effect of plasma hyperosmolality on the thermoregulatory responses to heat stress should
be attenuated with the reduction of
[Na+]sweat due to heat acclimatization.
Eleven subjects (9 male and 2 female) were passively heated by
immersing their lower legs into water at 42°C (room temperature
28°C and relative humidity 30%) for 50 min following isotonic or
hypertonic saline infusion. We determined the increase in the
esophageal temperature (Tes) required to elicit sweating
and cutaneous vasodilation (CVD) (
Tes thresholds for
sweating and CVD, respectively) in each condition and calculated the
elevation of the Tes thresholds per unit increase in
Posmol as the osmotic inhibition of sweating and CVD. The
osmotic shift in the Tes thresholds for both sweating
and CVD correlated linearly with [Na+]sweat
(r = 0.858 and r = 0.628, respectively). Thus subjects with a lower
[Na+]sweat showed a smaller osmotic elevation
of the Tes thresholds for sweating and CVD. These
results suggest the possibility that heat acclimatization attenuates
osmotic inhibition of thermoregulatory responses as well as reducing
[Na+]sweat.
osmoregulation; sweating; cutaneous vasodilation; plasma osmolality; vasopressin
This article has been cited by other articles:
|
|
 |
|
  M. J. Buono, K. D. Ball, and F. W. Kolkhorst Sodium ion concentration vs. sweat rate relationship in humans J Appl Physiol, September 1, 2007; 103(3): 990 - 994. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y.-I. Kamijo, T. Okumoto, Y. Takeno, K. Okazaki, M. Inaki, S. Masuki, and H. Nose Transient cutaneous vasodilatation and hypotension after drinking in dehydrated and exercising men J. Physiol., October 15, 2005; 568(2): 689 - 698. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Mitono, H. Endoh, K. Okazaki, T. Ichinose, S. Masuki, A. Takamata, and H. Nose Acute hypoosmolality attenuates the suppression of cutaneous vasodilation with increased exercise intensity J Appl Physiol, September 1, 2005; 99(3): 902 - 908. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Ito, T. Itoh, T. Hayano, K. Yamauchi, and A. Takamata Plasma hyperosmolality augments peripheral vascular response to baroreceptor unloading during heat stress Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2005; 289(2): R432 - R440. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Ichinose, K. Okazaki, S. Masuki, H. Mitono, M. Chen, H. Endoh, and H. Nose Ten-day endurance training attenuates the hyperosmotic suppression of cutaneous vasodilation during exercise but not sweating J Appl Physiol, July 1, 2005; 99(1): 237 - 243. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Michikami, A. Kamiya, Q. Fu, S. Iwase, T. Mano, and K. Sunagawa Attenuated thermoregulatory sweating and cutaneous vasodilation after 14-day bed rest in humans J Appl Physiol, January 1, 2004; 96(1): 107 - 114. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. F. DiBona Thermoregulation Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2003; 284(2): R277 - R279. [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
