Effects of Physical Training on Heat Loss Responses in Young Women

Accession number;03A0438033
Title;Effects of Physical Training on Heat Loss Responses in Young Women
Author; OGURA YUKIO (Osakakokusaidaigakutandai) KUWAHARA TOMOKO (Kobe Univ., Graduate School, JPN) INOUE YOSHIMITSU (Osaka Int. Univ.)
Journal Title;Descente Sports Science
Journal Code:L0988A
ISSN:0285-5739
VOL.24;NO.;PAGE.86-95(2003)
Figure&Table&Reference;FIG.4, TBL.3, REF.19
Pub. Country;Japan
Language;Japanese
Abstract;To examine the effects of physical training on heat loss responses of young women in relation to menstrual cycles, 11 physically trained (T group) and 13 untrained (U group) women were exposed to passive heating (by placing the lower legs and feet in a 42.DEG.C. water bath for 60 min while sitting in a warm (30.DEG.C., 45%RH) chamber) in their mid-follicular and mid-luteal phases. Female hormones on the experimental day increased from the mid-follicular to mid-luteal phase in the T and U groups, but the magnitude of increase was significantly lower in the T group. During the passive heating, rectal (Tre) and mean skin temperatures were significantly lower in the T group than in the U group regardless of the menstrual phase. Although Tre and mean body (Tb) temperatures before and during the heating increased from the mid-follicular to the mid-luteal phase in the U groups, the tendency was not observed in the T group. Therefore the group differences of Tre and Tb were more remarkable in the mid-luteal phase. The increase of skin blood flow measured by laser-Doppler flowmetry (%LDF) did not differ between the groups regardless of body site and menstrual phase. Local sweating rate (msw) was significantly greater in the T group than in the U group on chest, back and forearm (but not on forehead and thigh) in the both menstrual phases, but no menstrual phase-related differences were observed in either group. Analysis of the relationship of the frequency of sweat expulsion (Fsw)-Tb, msw-Fsw or %LDF-Tb suggested that in women physical training improves sweating and vasodilation functions, and central and peripheral mechanisms in the sweating function and central rather than peripheral mechanism in the vasodilation function.... (author abst.)