Study: Sedentary Lifestyles Can Accelerate Biological Aging

Scientists have long associated a sedentary lifestyle with many diseases, ranging from obesity to heart problems, diabetes, and early death. It is easy to understand why: a decrease in activity contributes to weight gain, which, in turn, is a risk factor for myocardial infarction, stroke, hypertension and unhealthy blood sugar levels.

In addition, a sedentary lifestyle has a negative effect on cells at the biological level, according to research by scientists at the University of California, San Diego medical school. They found that women who practice moderate or intense physical activity for less than 40 minutes a day and spend more than 10 hours a day sitting have shorter telomeres - tiny “caps” that are located at the ends of DNA chains. They protect chromosomes from damage and gradually shorten with age.
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Telomeres will shorten faster if a person suffers from obesity or constantly smokes. Reducing their length can also lead to cardiovascular diseases, diabetes and the main types of cancer.

During the study, researchers found that women who lead a sedentary lifestyle have shorter telomeres than those who are engaged in mobile activities. They were led to such a conclusion by a blood test of almost 1500 women aged from 64 to 95 years old, who are in the program of the Women's Health Initiative . In this case, the team of researchers focused on telomeres, which, due to their peculiarities, can be markers of cell age. Researchers compared telomere lengths to see if physical activity affects aging.

Previous studies have also studied the relationship between telomere length and physical activity, but relied only on the words of participants in the experiment about their level of activity, which is often inaccurate. Instead of surveys, scientists relied on more objective records of physical activity from accelerometers that women carried for one week. At first, they did not find any connection between the telomere length and the level of physical activity, but when they focused on those women who do not practice the recommended half-hour physical exertion daily, they found interesting patterns.

Women who do not pay attention to physical activity and lead a sedentary lifestyle (more than 10 hours a day) have shorter telomeres than those who spend less time in a sitting position. Scientists estimate that shortening telomeres adds about 8 years to a woman’s age. This means that the body of sedentary women is aging faster than those who move as little, but also sit at the same time less.

Those women who received the recommended amount of daily exercise did not demonstrate any relationship between how much time they spent sitting and the length of their telomeres. Scientists suggest that physical activity can counteract telomere reduction that occurs as it ages.

Several mechanisms can explain the connection between time spent sitting and telomere shortening: oxidative stress and telomere inflammation accelerate depletion of the body. The results show that regular exercise increases the activity of antioxidants and can cause an anti-inflammatory reaction. Therefore, it is possible that women who spend long hours sitting in combination with less time spent on physical activity are not exposed to these antioxidants and anti-inflammatory remedies.

Previously, this relationship could be explained by obesity. In previous studies, a sedentary lifestyle was associated with an increased risk of obesity, and this, in turn, with a decrease in telomeres. However, after adjusting the weight, the results were maintained. But one cannot rule out a possible reverse causal relationship with chronic diseases. That is, women who have a history of chronic diseases are likely to have little movement, leading to telomere shortening.

The exact time of activity, which will nullify the effect of aging from prolonged sitting, has not yet been determined. The World Health Organization recommends that adults over the age of 18 spend 150 minutes a week in classes with moderate or 75 minutes with high intensity exercise.

But this study demonstrates that a sedentary lifestyle potentially affects cell aging, and exercise can be one of the ways to combat this process.

Scientific work published in the journal American Journal of Epidemiology January 18, 2017
DOI: 10,1093 / AJE / kww196