Heat Acclimation Improves Cutaneous Vascular Function and Sweating in Trained Cyclists.
Summary of "Heat Acclimation Improves Cutaneous Vascular Function and Sweating in Trained Cyclists."
The aim of this study was to explore heat acclimation effects on cutaneous vascular responses and sweating to local acetylcholine (Ach) infusions and local heating. We also examined if heat acclimation altered maximal skin blood flow. Ach (1, 10, and 100mM) was infused in 20 highly trained cyclists via microdialysis before and after a 10-day heat acclimation (2 x 45 min exercise at 50% VO(2max) in 40°C; n = 12) program or control conditions (2 x 45 min exercise at 50% VO(2max) in 13°C; n = 8). Skin blood flow was monitored via laser-Doppler flowmetry (LDF) and cutaneous vascular conductance (CVC) was calculated as LDF/MAP. Sweat rate was measured by resistance hygrometry. Maximal forearm skin blood flow (FBF) was obtained by heating the contralateral forearm in a water spray device and measured by Doppler ultrasound. Heat acclimation increased CVC to 1, 10, and 100 mM Ach (43.5 ± 3.4 vs. 52.6 ± 2.6 %CVC(max); 67.7 ± 3.4 vs. 78.0 ± 3.0 %CVC(max); 81.0 ± 3.8 vs. 88.5 ± 1.1 %CVC(max); all P < 0.05). Maximal FBF remained unchanged after heat acclimation (290.9 ± 12.7 vs. 269.9 ± 23.6 ml min(-1)). The experimental group showed significant increases in sweating responses to 10 and 100 mM of Ach (0.21 ± 0.03 vs. 0.31 ± 0.03 mg cm(-2) min(-1); 0.45 ± 0.05 vs. 0.67 ± 0.06 mg cm(-2) min(-1); all P < 0.05) but not to 1 mM Ach (0.13 ± 0.02 vs. 0.18 ± 0.02 mg cm(-2) min(-1); p =0.147). Heat acclimation in highly trained subjects induced local adaptations within the skin microcirculation and sweat gland apparatus. Furthermore, maximal skin blood flow was not altered by heat acclimation, demonstrating that the observed changes were attributable to improvement in cutaneous vascular function and not due to structural changes that limit maximal vasodilator capacity.
Affiliation
1University of Oregon.
Journal Details
This article was published in the following journal.
Name: Journal of applied physiology (Bethesda, Md. : 1985)
ISSN: 1522-1601
Pages:
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/20864556
- DOI: http://dx.doi.org/10.1152/japplphysiol.00725.2010
Medical and Biotech [MESH] Definitions
Heat Exhaustion
A clinical syndrome caused by heat stress, such as over-exertion in a hot environment or excessive exposure to sun. It is characterized by SWEATING, water (volume) depletion, salt depletion, cool clammy skin, NAUSEA, and HEADACHE.
Hsp72 Heat-shock Proteins
Stress-inducible members of the heat-shock proteins 70 family. HSP72 heat shock proteins function with other MOLECULAR CHAPERONES to mediate PROTEIN FOLDING and to stabilize pre-existent proteins against aggregation.
Zidovudine
A dideoxynucleoside compound in which the 3'-hydroxy group on the sugar moiety has been replaced by an azido group. This modification prevents the formation of phosphodiester linkages which are needed for the completion of nucleic acid chains. The compound is a potent inhibitor of HIV replication, acting as a chain-terminator of viral DNA during reverse transcription. It improves immunologic function, partially reverses the HIV-induced neurological dysfunction, and improves certain other clinical abnormalities associated with AIDS. Its principal toxic effect is dose-dependent suppression of bone marrow, resulting in anemia and leukopenia.
Antiperspirants
Agents that are put on the SKIN to reduce SWEATING or prevent excess sweating (HYPERHIDROSIS).
Sweating, Gustatory
An autonomic disorder characterized by excessive sweating of the forehead, upper lip, perioral region, or sternum subsequent to gustatory stimuli. The auriculotemporal syndrome features facial flushing or sweating limited to the distribution of the auriculotemporal nerve and may develop after trauma to the parotid gland, in association with PAROTID NEOPLASMS, or following their surgical removal. (From Ann Neurol 1997 Dec;42(6):973-5)
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