A study published in JAMA Oncology reports findings that a greater amount of sedentary time was associated with a higher risk of cancer mortality for middle-aged and older US adults. The study suggests that exchanging sedentary time with light, moderate, or vigorous physical activity was associated with reduced cancer mortality risk.
Conducted by researchers from The University of Texas MD Anderson Cancer Center, the study involved 8,002 participants without a cancer diagnosis from the REGARDS study, which recruited more than 30,000 U.S. adults over the age of 45 between 2003 and 2007 to study long-term health outcomes. The participants wore an accelerometer to measure their active and sedentary behavior. After a mean follow-up of 5 years, 268 participants from the initial cohort had died of cancer.
The researchers determined that those who experienced longer durations of sedentary behavior were associated with a greater risk of cancer death, demonstrating up to 82% higher risk of cancer mortality compared to the least sedentary individuals. While sedentary behavior is known to be associated with diabetes, cardiovascular disease, and all-cause mortality, this is one of fewer studies focusing on the direct association between cancer and sedentary behavior and physical activity.
"This is the first study that definitively shows a strong association between not moving and cancer death," said lead author Susan Gilchrist, M.D., associate professor of Clinical Cancer Prevention. "Our findings show that the amount of time a person spends sitting prior to a cancer diagnosis is predictive of time to cancer death."
But the researchers urge people not to despair, for even replacing a minimal amount of sedentary time (30 minutes) with moderately-intense vigorous physical activity (like biking) was associated with a 31% lower risk of cancer death. For light-intensity activity, like walking, an 8% lower risk of cancer death was seen.
"Conversations with my patients always begin with why they don't have time to exercise," said Gilchrist, who leads MD Anderson's Healthy Heart Program. "I tell them to consider standing up for 5 minutes every hour at work or taking the stairs instead of the elevator. It might not sound like a lot, but this study tells us even light activity has cancer survival benefits."