SAN DIEGO — Moderate exercise equivalent to a brisk 1-hour walk 4 days a week improved insulin sensitivity in a group of women with polycystic ovary syndrome, even in the absence of weight loss, results from a small trial suggest.
The finding is important because obese women with polycystic ovary syndrome (PCOS) “have often been told to lose weight,” Ann J. Brown, M.D., told this newspaper during a poster session at the annual meeting of the Androgen Excess Society. “They know that they need to lose weight, but it's very difficult [for them]. This is a hopeful message that even just picking up the pace of activity will improve your metabolic profile.”
For the 5-month study, she and her associates randomized 19 sedentary women aged 22–41 years with PCOS to one of two groups. One group of 11 women continued their sedentary lifestyle, while another group of 8 women participated in a monitored exercise program that equaled about 230 min/wk at 60% maximal oxygen uptake, “the equivalent of a brisk walk,” said Dr. Brown of the division of endocrinology, metabolism, and nutrition in the department of medicine at Duke University Medical Center, Durham, N.C.
Study participants completed a 75-g oral glucose tolerance test and a frequently sampled intravenous glucose tolerance test before and after the intervention. The investigators calculated insulin sensitivity and area under the curve (AUC) for glucose and insulin.
At baseline, the women in both groups were similar in age, aerobic fitness level, body mass index, blood pressure, fasting insulin, insulin AUC, and insulin sensitivity. At the end of 5 months, aerobic fitness in the sedentary group worsened by 2.3%, compared with a 4.3% improvement in the exercise group, a statistically significant difference. BMI and waist circumference did not change in either group.
Fasting insulin decreased significantly in the exercise group, compared with the sedentary group (−4.6% vs. +8.9%), as did insulin AUC (−26.0% vs. +1.4%).