Ischaemia in working muscles potentiates the exercise-induced sweating response in man.
OBJECTIVE
The purpose was to examine whether graded ischaemia in the working muscles affects the rate of sweating and the control of exercise core temperature.


METHODS
Eight subjects performed cycle ergometry exercise in the supine position with (ischaemic exercise) and without (control exercise) restriction of blood flow in the contracting muscles, accomplished by exposure of the legs to a supra-atmospheric pressure of 6.6 kPa. Each subject performed one exhaustive incremental work rate trial and one steady-state exercise trial (at 33% of control peak work rate), in both the control and ischaemia conditions.


RESULTS
Ischaemia decreased work performance by 45% so that in this condition the steady-state work rate level corresponded to 63% of ischaemic peak work rate. Ischaemia did not affect the oesophageal temperature equilibrium in the steady-state trials, but potentiated the exercise sweating response. Exercise responses of mean arterial pressure, heart rate and pulmonary ventilation were potentiated by ischaemia.


CONCLUSIONS
During ischaemic exercise sweat secretion was potentiated by non-thermal and/or local thermal stimuli.
Eiken
O
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Swedish Defence Research Agency, Defence Medicine, Karolinska Institutet, Stockholm, Sweden.
Mekjavic
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IB
D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007511:Ischemia / Q000503:physiopathology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000098:blood supply*; D013546:Sweating / Q000502:physiology*