Stay Active and Age Slower

08/02/2017

According to Aladdin Shadyab, Ph.D, leader of the study published in the American Journal of Epidemiology, "Our study found cells age faster with a sedentary lifestyle. Chronological age does not always match biological age ... We found that women who sat longer did not have shorter telomere length if they exercised for at least 30 minutes a day, the national recommended guideline."

In order to fully comprehend this study, it's important to understand how cells regulate themselves as they react to internal and external stimuli. Among other things, our cells contain telomeres, repetitive sections of DNA found at the end of chromosomes. These structures protect chromosomes from deteriorating, in a way that is fairly similar to shoelaces fraying or hair splitting. As it turns out, telomere length is closely associated with both aging and disease, including serious conditions such as cancer, diabetes, and heart disease. Telomeres, leukocyte telomere length (LTL) specifically, have been linked with a number of lifestyle factors such as exercise, smoking, and body mass index.

In the study, participants who were more sedentary were also more likely to be obese, more likely to have a history of chronic diseases, more likely to have experienced a fall in the past 12 months, and less likely to be in excellent or very good health. While we have long understood the importance of telomere length, up until now, there have been no studies that measured sedentary time objectively by accelerometer and no studies that measured variations in LTL by level of physical activity. Movement was captured along 3 axes by study participants - vertical, anteroposterior, and mediolateral - with a calibration routine used to define different levels of sedentary behaviour and physical activity intensity.  

Using a number of linear regression models, Shadyab and his fellow researchers examined the association between LTL and sedentary time and investigated whether the associations varied according to how much moderate or vigorous physical activity the participants engaged in daily. In an amazing finding, women who exercised for under 40 minutes and were sedentary for more than 10 hours per day had cells that were eight years older than women who were less sedentary and exercised more. According to Shadyab, "Discussions about the benefits of exercise should start when we are young, and physical activity should continue to be part of our daily lives as we get older, even at 80 years old."

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