Exercise and Sleep Linked to Reducing Cancer Risk

Sleep is becoming recognized as more critical to overall health and well-being than previously recognized, and much research is underway investigating the relationship between sleep quality, duration, and the risk of various diseases and conditions. It has already been determined that sleep disorders such as sleep apnea are consistently associated with a higher risk of serious conditions such as heart disease, stroke, and diabetes, not to mention daytime fatigue and increased auto accidents. Sleep apnea is a serious condition in which breathing ceases temporarily due to an obstructed airway and blood oxygen levels drop, up to hundreds of times a night.

This novel study represents a new area of research: how sleep quality affects your risk of cancer. The study was conducted by evaluating the association between exercise, sleep duration and the incidence of cancer in general, breast cancer, and colon cancer. Nearly 6,000 women over 18 years of age completed surveys in 1998 and were tracked for 10 years through registries in the US. The results indicated that nighttime sleep affects the relationship between exercise and cancer risk in women. Women who exercised the most (those in the upper 50% in terms of physical activity) had a significantly reduced risk of overall cancer and breast cancer. However, sleeping less than 7 hours per day nearly eliminated the protective effect of exercise.

James McClain, Ph.D., cancer prevention fellow at the National Cancer Institute and lead author of the study, believes that physical activity has an effect on body weight, hormones and immune function, all of which contribute to a person’s individual cancer risk. In addition, he notes the increasing evidence about the detrimental effects of insufficient and poor quality sleep. McLain says "Greater participation in physical activity has consistently been associated with reduced risk of cancer incidence at several sites, including breast and colon cancers. Poor sleeping habits appear 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."

Common symptoms of sleep apnea include loud snoring, sudden nighttime awakenings, and daytime fatigue. Bed partners usually notice the snoring and gasping that occur among sleep apnea patients. If you or your loved ones exhibit any of these signs, it’s very important to ask your doctor or a sleep specialist about testing for sleep apnea. Effective treatment for sleep apnea is available, and if left untreated, more and more research reveals that the consequences can be life threatening.