Lack of sleep negates exercise benefits, flares-up cancer risk

Washington, November 18: Benefits of a good night’s sleep are well-touted. So are the benefits of a daily exercise regime. But when put into practice together, they guard the body against cancerous tumors, a new study suggests.

Inversely, cutting down night’s sleep not only wipes out the benefits of exercise but also increases the risk of developing cancers, results warn.

The study conducted at the U.S. National Cancerdefine Institute in 1998 monitored almost 6,000 middle-aged women with no cancer history for 10 years. The study essentially assessed the relationship between physical activity energy expenditure (PAEE), length of sleep and occurrence of breast and colondefine cancer.

During the 10-year follow-up, 604 cases of cancer, including 186 breast cancer tumors were recorded.

While avid exercisers were 25 percent less likely to develop malignancies, the benefits of exercise turned ‘worthless’ for women who slept for fewer than seven hours a night, researchers averred.

Women aged below 65 and getting inadequate sleep lost out on the shielding impact of the exercise. Chances of these women getting affected by cancer were 47 higher, the study revealed.

James McClain, cancer prevention fellow at the National Cancer Institute and lead author of the study said, “Greater participation in physical activity has consistently been associated with reduced risk of cancer incidence at several sites, including breast and colon cancers."

Although unsure, the researchers thought that hormone levels, immunity of an individual, weight of the body may have a bearing in exercise reducing cancer risk.

McClain added, "Short duration sleep appears to have opposing effects of physical activity on several key hormonal and metabolic parameters, which is why we looked at how it affected the exercise/cancer risk relationship."

The results were tabled at the American Association for Cancer Research international conference in Washington yesterday.