Comparison Of Changes In Fasting Glucose Levels After Aerobic Exercise Training In Pre- And Post-menopausal African American Women

Abstract

African American women have the greatest incidence rate of type II diabetes amongst all ethnic groups in the United States. Moreover, menopause confers a greater risk for the onset of type II diabetes. Aerobic exercise training (AEXT) has been well demonstrated to improve glucose metabolism and aid in the prevention of type II diabetes; however the effects of menopausal status on the exercise-induced adaptations in glucose metabolism have not been previously investigated. PURPOSE: To investigate the effects of a 6-month AEXT intervention on fasting plasma glucose levels in pre- and post-menopausal African American women without clinically diagnosed type II diabetes. METHODS: 17 female African Americans who were sedentary, non-diabetic (<126 mg/dL), non-smoking, free of cardiovascular disease and not on antihypertensive medication completed 6 months of supervised AEXT (3 days/week, 65% of VO2max, 40 min/session). 6-weeks prior to initiation of AEXT, subjects underwent dietary stabilization and were required to follow an AHA low fat, low salt diet for the duration of the study. Before and after AEXT, fasted blood samples were collected and measured for plasma glucose levels. RESULTS: Pre- (n = 9; 51.7 ± 5.1 yrs) and post-menopausal (n = 8; 54.3 ± 6.2 yrs) women were similar in BMI, % body fat, and VO2max at baseline. The absolute change (pre-menopause: -8.4 ± 7.6; post-menopause: 0.87 ± 6.1 mg/dL; p =.015) and % change (pre-menopause: -8.8 ± 7.6; post-menopause: 1.4 ± 7.5%; p =.014) in plasma glucose levels from pre-AEXT levels were significantly different between pre- and post-menopausal women. This difference remained significant after adjusting for the change in BMI and % body fat. Sub-analysis of each menopause group showed that plasma glucose levels were significantly decreased in pre-menopausal women after AEXT (pre: 93.1 ± 9.3; post: 84.6 ± 8.6 mg/dL; p =.010), however there was no significant change in plasma glucose levels in post-menopausal women (pre: 89.3 ± 9.7; post: 90.2 ± 7.9 mg/dL; p =.701). CONCLUSIONS: In African American women, fasting plasma glucose levels improved following AEXT in pre-menopausal, but remained unchanged in post-menopausal women. These preliminary findings suggest that exercise-induced adaptations in glucose metabolism are attenuated in post-menopausal African American women.