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This Article Full Text Full Text (PDF) All Versions of this Article: 107/1/90    most recent 91568.2008v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Zarins, Z. A. Articles by Brooks, G. A. PubMed PubMed Citation Articles by Zarins, Z. A. Articles by Brooks, G. A.

Training improves the response in glucose flux to exercise in postmenopausal women

Exercise Physiology Laboratory, Department of Integrative Biology, University of California, Berkeley, California

Submitted 3 December 2008 ; accepted in final form 15 May 2009

We examined the effects of endurance training on parameters of glucose flux during rest and exercise in postmenopausal women. Ten sedentary, but healthy women (55 ± 1 yr) completed 12 wk of endurance exercise training on a cycle ergometer [5 days/wk, 1 h/day, 65% peak oxygen consumption (O_2peak)]. Flux rates were determined by primed continuous infusion of [6,6-²H]glucose (D₂-glucose) during 90 min of rest and 60 min of cycle ergometer exercise during one pretraining exercise trial [65% O_2peak (PRE)] and two posttraining exercise trials [the power output that elicited 65% pretraining O_2peak (ABT) and 65% posttraining O_2peak (RLT)]. Training increased O_2peak by 16.3 ± 3.9% (P < 0.05). Epinephrine and glucagon were lower during ABT and lactate was lower during ABT and RLT (P < 0.05), but the apparent insulin response was unchanged. Whole body glucose rate of appearance decreased posttraining during exercise at a given power output (4.58 ± 0.39 mg·kg^–1·min^–1 during ABT compared with 5.21 ± 0.48 mg·kg^–1·min^–1 PRE, P < 0.05), but not at the same relative workload (5.85 ± 0.36 mg·kg^–1·min^–1). Training resulted in a 35% increase in glucose MCR during exercise at the same relative intensity (7.16 ± 0.42 ml·kg^–1·min^–1 during RLT compared with 5.28 ± 0.42 ml·kg^–1·min^–1 PRE, P < 0.05). Changes in parameters of glucose kinetics during exercise were accomplished without changes in dietary composition, body weight, or body composition. We conclude that despite changes in the hormonal milieu that occur at menopause, endurance training results in a similar magnitude in training-induced alterations of glucose flux as seen previously in younger women.

menopause; glucose kinetics; body composition; exertion; exercise training