Effect of luteal phase elevation in core temperature on forearm
blood flow during exercise.
Kolka, Margaret A., and Lou A. Stephenson.
Thermal and Mountain Medicine Division, U.S. Army Research
Institute of Environmental Medicine, Natick, MA 01760-5007
APStracts 3:0526A, 1996.
Forearm blood flow (FBF), as an index of skin blood flow in the
forearm was measured in five healthy women by venous occlusion
plethysmography (VOP) during leg exercise at 80% peak aerobic power
and Ta= 35 degrees C (rh = 22%; Tdp = 10 degrees C). Resting
esophageal temperature (Tes) was 0.3+/-0.1 degrees C higher in the
mid-luteal than the early follicular phase of the menstrual cycle
(p<0.05). Resting FBF was not different between menstrual cycle
phases. The Tes threshold for onset of skin vasodilation was higher
(37.4+/-0.2 degrees C) in mid-luteal than early follicular phase
(37.0+/-0.1 degrees C; p<0.05). The slope of the FBF to Tes
relationship was not different between menstrual cycle phases
(14.0+/-4.2, early follicular and 16.3+/-3.2 ml x 100ml-1 x min-1 x
degrees C-1, mid-luteal ). Plateau FBF was higher during exercise in
mid-luteal (14.6+/-2.2 ml x 100ml-1 x min-1 x degrees C-1) compared
to early follicular (10.9+/-2.4 ml x 100ml-1 x min-1 x degrees C-1;
p<0.05) The attenuation of the increase in FBF to Tes occurred
when Tes was 0.6 degrees C higher and at higher FBF in mid-luteal
than early follicular experiments (p<0.05). In summary, the
forearm blood flow response is different during exercise in the two
menstrual cycle phases studied. After the attenuation of the increase
in forearm blood flow and while Tes was still increasing, the greater
forearm blood flow in the mid-luteal phase may have been due to the
effects of increased endogenous reproductive endocrines on the
cutaneous vasculature.
Received 12 February 1996; accepted in final form 13 November
1996.
APS Manuscript Number A144-6.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996