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Brief Description:

Exercise is good for more than just your waistline. Results from research point to a sleep-exercise link when it comes to cancer prevention in women

Transcript:

Balintfy: A recent study presented at an American Association for Cancer Research conference suggests that regular physical activity can lower a woman’s overall risk of cancer—but only if she gets a good night’s sleep. Dr. James McClain at the National Cancer Institute explains that a lack of sleep can undermine exercise’s cancer prevention benefits.

McClain: The major findings of this study, although preliminary, are that among younger and more active women, a short duration of sleep appears to be associated with increased cancer risk.

Balintfy: Even though the exact mechanism of how exercise reduces cancer risk isn’t known, researchers believe that physical activity’s effects on factors including hormone levels, immune function, and body weight may play an important role.

McClain: We know quite a bit about the association between, the relationship between physical activity and cancer. We know that the more active you are, the more you reduce your risk of developing cancer. There have been a few studies that have looked at the relationship between sleep duration and cancer. Some of those have found that shorter duration sleep can increase your risk for cancer, but there’s been some mixed results on that. We were interested in the relationship between physical activity, sleep, and cancer just because we know there’s a lot of effects, beneficial effects of physical activity that seemed to be counterbalanced by the effects of short duration of sleep, so we wondered if maybe the relationship would change.

Balintfy: The study examins the link between exercise and cancer risk, paying special attention to whether or not getting adequate sleep further affects a women’s cancer risk. But Dr. McClain points out that the association of physical activity and sleep does not necessarily prevent cancer.

McClain: Sleep in our study did not prevent you from getting cancer, so you can’t just go and sleep more and reduce your risk of getting cancer. What we did find is that among the most active women in our study—these younger, more active women—that if they slept more than seven hours, they were protected relative to those who slept less than seven hours. So the women who were younger and more active, sleeping less than seven hours experienced more cancer, about one and a half times as much.

Balintfy: Dr. McClain adds that the study was a cohort of about 6,000 women. Their physical activity and sleep was measured at the beginning. Then they were followed over a period of 10 years to see what kind of outcomes they experienced. For more on this study and other cancer research, visit www.cancer.gov. This is Joe Balintfy, National Institutes of Health, Bethesda, Maryland.