Too Much Sitting Ages You by 8 Years
What to Know
Found in our body’s cells, telomeres are the cap at the end of a strand of DNA. They protect our genes and help our cells do their job properly. As we get older, however, our telomeres get shorter and start to fray. It’s a natural part of aging. When they start to deteriorate—the pace varies from person to person—the risk of heart disease, type 2 diabetes, some cancers, and other health problems increases. Keeping physically fit can help maintain the health of your telomeres and protect your health overall. For this study, researchers wanted to explore the aging process of telomeres and how physical inactivity affects it.
Participants included 1,481 African American and white women whose average age was 79. Just over 20 percent of them had diabetes. The women answered questions about how long they sat and lay down during a typical day, as well as how many hours they regularly slept at night. Then, for seven days, each of the women wore an accelerometer, a device that measures physical activity. The women also provided DNA samples so that the researchers could measure the length of their telomeres.
Women who did not get 30 minutes of exercise per day—the recommended amount to maintain health—and who sat for more than 10 hours had shorter telomeres than more active women. In fact, the length of their telomeres indicated that they were eight years older biologically than they were chronologically. However, it appears that exercise can balance the hazards associated with sitting too long. The women who worked out for at least 30 minutes per day did not have shorter telomeres, even if they sat for 10 hours or more.
The researchers could not determine if lack of exercise alone caused the shortening of the women’s telomeres, aging them prematurely. Many of the women had health problems, including diabetes, which might increase the pace at which telomeres shorten and, perhaps, prevent them from exercising. But the study does provide more evidence that staying active, no matter what your age, can help protect you against the march of time. Exercise, the researchers write, helps to reduce inflammation, which may otherwise damage your cells’ telomeres. Insulin resistance, caused in part by a sedentary lifestyle, may also accelerate the deterioration of telomeres and speed up the aging process.
“Associations of Accelerometer-Measured and Self-Reported Sedentary Time With Leukocyte Telomere Length in Older Women.” Aladdin H. Shadyab, Caroline A. Macera, Richard A. Shaffer, Sonia Jain, Linda C. Gallo, Michael J. LaMonte, Alexander P. Reiner, Charles Kooperberg, Cara L. Carty, Chongzhi Di, Todd M. Manini, Lifang Hou, and Andrea Z. LaCroix. American Journal of Epidemiology, Jan. 18, 2017. 185(3): 172-84.