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Insulin Sensitivity Increases with Physical Exercise in Hypertensive Subjects
A DGReview of :"Effects of Mild Exercise on Insulin Sensitivity in Hypertensive Subjects"
Hypertension
05/24/2002
By Veronica Rose
Insulin sensitivity appears to increase in hypertensive patients after exercise, and the increase does not appear to be associated with enhanced cardiac output.
A relationship between increased insulin sensitivity following exercise in conditions associated with insulin resistance--such as obesity and diabetes--was already recognised. The effect of exercise on insulin sensitivity in hypertension, however, was unknown.
Researchers at the Laval University Hospital Research Unit, Quebec, Canada, examined whether post-exercise changes in haemodynamics and /or changes in insulin-induced vasodilatation could increase insulin sensitivity in hypertension.
Insulin sensitivity was assessed in ten hypertensive and 10 normotensive subjects at four periods: during a control evaluation; during lower body negative pressure; following 30 minutes of mild bicycle exercise; and during lower body negative pressure after exercise.
Researchers assessed insulin-induced vasodilation from peak forearm blood flow during an insulin glucose tolerance test.
There was no change among hypertensive subjects in insulin sensitivity during lower body negative pressure, but it increased following exercise and remained high during lower body negative pressure after exercise. Insulin sensitivity was unchanged in normotensive subjects.
A lower cardiac output and insulin sensitivity was noted in hypertensive as opposed to normotensive subjects. There was a decrease in cardiac output during lower body negative pressure, but it increased following exercise. Cardiac output recorded for both groups during lower body negative pressure after exercise was similar to that recorded during the control evaluation.
A significantly lower peak forearm blood flow was noted in hypertensive subjects than in the normotensive subjects, despite higher insulin levels in hypertensives. Insulin levels among hypertensive subjects were not modified during lower body negative pressure or following exercise, say researchers.
They concluded that endogenous insulin-induced vasodilatation was reduced in hypertensive subjects and this insulin action is unaffected by physical exercise.
Hypertension 2002 Vol 39 pp 989.
"Effects of Mild Exercise on Insulin Sensitivity in Hypertensive Subjects"
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