Menopause: Exercise No Cure for Hot Flashes

Norra MacReady

August 01, 2013

Exercise may be no better than sitting on the sidelines when it comes to relieving hot flashes during menopause, a new study suggests.

Women participating in a 12-week exercise program did not report significant changes in the number or intensity of hot flashes, or vasomotor symptoms (VMS), compared with sedentary women who followed their usual level of activity in a randomized controlled trial.

Barbara Sternfeld, PhD, from the Division of Research, Kaiser Permanente, Oakland, California, and colleagues report the trial results in an article published online July 29 in Menopause. The study was conducted under the auspices of the Menopause Strategies: Finding Lasting Answers for Symptoms and Health (MsFLASH) Research Network.

These findings come after years of conflicting data in which "about half of observational studies report no association, the remaining studies generally suggest a protective association, and a few studies report increased VMS with higher levels of activity," they write.

Dr. Sternfeld and coauthors randomly assigned the participants into 1 of 3 groups: exercise, consisting of 12 weeks of individualized cardiovascular training 3 times per week; a control group, in which each woman pursued her usual daily activities; and a group taking a 12-week yoga class, whose data were not included in the current analysis.

Each woman was further randomly assigned to take a daily capsule of fish oil or a placebo. This "factorial design ensured that all participants could believe that they were receiving some intervention and, hence, had an expectancy of benefit," the authors explain.

Women were eligible for the study if they were between 40 and 62 years of age, late perimenopausal or menopausal or posthysterectomy with follicle-stimulating hormone levels greater than 20 mIU/mL or estradiol levels no higher than 50 pg/mL, and experienced VMS at least 14 times per week for 3 consecutive weeks, with the symptoms rated as severe or bothersome on a 4-point scale. Exclusion criteria included body mass index greater than 37 kg/m2, use of hormones or hormonal contraceptives within the past 2 months, current regular participation in exercise or yoga, or current use of fish oil supplements.

There were 106 women in the exercise group and 142 in the usual-activity group. Their mean ages were 55.8 and 54.2 years, respectively. In an intention-to-treat analysis, which included all participants with available follow-up data regardless of their adherence to the exercise regimen, women in the exercise group reported a mean of 7.3 hot flashes (95% confidence interval [CI], 6.7 - 7.9) per day at baseline compared with a mean of 8.0 (95% CI, 7.3 - 8.7) in the usual-activity group (P = .434). By week 12, mean daily VMS had decreased by 2.4 (95 CI, −3.0 to −1.7) among the 101 women remaining in the exercise group compared with a reduction of 2.6 (95% CI, −3.2 to −2.0) among the 135 women in the control group (P = .745). A similar pattern was seen in a sensitivity analysis that included only women who attended at least 80% of the exercise classes.

In an analysis of secondary outcomes, with statistical significance set at P < .0125, women in the exercise group did experience significant improvements in sleep quality compared with the usual-activity group (P = .007), but in not insomnia severity (P = .025). Relief of depression and anxiety also were not significant between the groups (P = .028 and .156, respectively).

Study limitations include both reliance on the participants' self-reports of VMS, rather than using more objective physiological measures, and the use of a constant level of exercise instead of a regimen that stressed progressively harder or more individualized activity.

At least one outside expert urges caution in interpreting these findings. "I think the idea of this study is very good," Ruth Freeman, MD, told Medscape Medical News. However, she believes the inclusion criteria were not stringent enough. "You need to start with enough hot flashes per week to have a reasonable chance of finding a difference," she explains. "The women in this study only had to have 14 per week, which is not a lot. So you can't see a huge difference, and that's a big problem." Contrast that with drug trials on VMS, which require at least 50 hot flashes per week, said Dr. Freeman, professor of medicine and obstetrics and gynecology, Albert Einstein College of Medicine, Bronx, New York. Dr. Freeman was not involved in this study.

However, she does agree with the authors' conclusion that exercise has little if any effect on VMS. "There's nothing wrong with exercise, but it won't cure your hot flashes."

This study was supported by the National Institute on Aging, the Eunice Kennedy Shriver National Institute of Child Health and Development, the National Center for Complementary and Alternative Medicine, and the Office of Research and Women's Health, and the Indiana Clinical and Translational Sciences Institute, funded in part by a grant from the National Institutes of Health, National Center for Research Resources, Clinical and Translational Sciences Award. The fish oil study supplement was donated, with matching placebo, by Nordic Naturals. Several authors report serving as a consultant or employee for various pharmaceutical companies; full disclosures can be found on the journal's Web site. The other authors and Dr. Freeman have disclosed no relevant financial relationships.

Menopause. Published online July 29, 2013. Abstract

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