30 Minutes of Daily Activity May Help Slow Chromosomal Aging

Even if you sit 10 hours a day, 30 minutes of activity may protect telomeres.

Posted Jan 20, 2017

Evgeny Atamanenko/Shutterstock
Source: Evgeny Atamanenko/Shutterstock

A new study by researchers at the University of California San Diego School of Medicine reports that 30 minutes of moderate-to-vigorous physical activity most days of the week may protect against accelerated biological aging caused by too much sitting. The findings were published this week in the American Journal of Epidemiology.

The researchers found that elderly women with less than 40 minutes of daily moderate-to-vigorous physical activity who also remained sedentary for more than 10 hours per day had shorter telomeres, which are a biological marker for chromosomal aging. 

One of the biggest health risks of living in a digital era is that so many of us are sitting for eight or more hours a day, oftentimes behind a digital screen. For millions of people from all walks of life and generations, sedentarism has become an unavoidable aspect of modern life. (Sedentarism is described as, "prolonged periods of sitting or overall inactivity which exacerbates health risks associated with a lack of dedicated exercise.")

In recent years, there has been an ongoing debate about whether (or not) short daily bouts of physical activity could negate the detrimental effects of sedentarism. The new study from UCSD sheds new light on this debate by comparing self-reported sedentary time with daily levels of physical activity through the lens of leukocyte telomere length in a cohort of 1,481 older women.

The research team believes they are the first to objectively measure how the combination of sedentary time and daily exercise can impact the leukocyte telomere length aging biomarker.

What Are Telomeres?

U.S. Department of Energy Human Genome Program/Public Domain
Human chromosomes (gray) capped by telomeres (white).
Source: U.S. Department of Energy Human Genome Program/Public Domain

Telomeres are DNA-protein structures that look like caps at the end of a chromosome. Telomeres protect and maintain the stability and integrity of each chromosome strand by preventing deterioration, shortening, or fusion with neighboring chromosomes. 

As our cells age, telomeres naturally shorten in length and tend to fray. A variety of lifestyle factors and daily habits such as chronic inactivity, stress, smoking, and obesity have been found to speed up the shortening of telomeres. Shortened telomeres are associated with accelerated cellular aging, cardiovascular disease, diabetes, and some cancers. 

The researchers conclude that too much sitting combined with too little physical activity is a double whammy that accelerates biological aging as marked by shortened telomeres. However, the good news is that women who tended to be sedentary for much of the day did not have shorter telomere length if they did some form of exercise for at least 30 minutes a day, most days of the week. 

The bad news is that elderly women who sat for more than 10 hours a day and were chronically inactive appeared eight years older biologically than their chronological age when compared to women who were sedentary but stayed active.  

According to Aladdin Shadyab, lead author of the study and postdoctoral scholar in the Department of Family Medicine and Public Health at the University of California  San Diego School of Medicine:

"Our study found cells age faster with a sedentary lifestyle. Chronological age doesn't 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.

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."

Future research by Shadyab and colleagues at UCSD will examine how exercise relates to telomere length in younger populations and in men. They also want to determine whether cardiorespiratory fitness modifies the relationship between sedentary time and telomere length. 

Hopefully, the initial findings of this research on the telomere-protecting benefits of physical activity can serve as a fresh source of motivation that inspires you to squeeze in at least 30 minutes of moderate to vigororous physical activity most days of the week regardless of your chronological age or gender

*As always, please make sure to consult with your primary care physician before beginning any new exercise routine.

References

Aladdin H. Shadyab et al. Associations of Accelerometer-Measured and Self-Reported Sedentary Time With Leukocyte Telomere Length in Older Women. American Journal of Epidemiology, January 2017 DOI: 10.1093/aje/kww196

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