BOB HIRSHON (host):
Exercise against cancer….I’m Bob Hirshon and this is Science Update.
We’ve all heard that exercise can reduce the risk of developing cancer. But if you’re an active woman under 65, the cancer-prevention benefits of exercise could be reversed if you don’t get enough sleep at night. Researchers studied physical activity and sleep in 6,000 women. After nearly ten years of follow-up, the physically active women had a 25% lower rate of all cancers. But according to behavioral scientist James McClain of the National Cancer Institute, in women under 65, a lack of sleep negated the anti-cancer benefits of exercise.
JAMES MCCLAIN (Institution):
Among young and active women, sleeping less than 7 hours increases their cancer risk by 47% vs. those young active women who got more sleep.
He and his colleagues aren’t sure why this is, but previous research has suggested that sleep deprivation impairs the immune system. I’m Bob Hirshon, for AAAS, the science society.