Fitness

Exercise: One Way It May Help You Live Longer

The relationship between physical activity and telomere length

Telomeres are minute bits of DNA that represent the ends of chromosomes. I often share with my patients that telomeres are like the little plastic aglets found on the ends of your shoelaces. Telomeres serve multiple purposes, including preventing our DNA from fraying or unraveling and preventing the DNA ends from entangling with one another.

Long telomeres, long life

Longer telomeres appear to be associated with longer life. Today we explore the relationship between physical activity such as exercise and telomere length.

We begin with the premise that as we age, our telomeres naturally shorten. Unfortunately, this means that our DNA cannot remain in good enough shape to allow for optimal cell division. Now, I should offer that whether shorter telomeres cause aging or vice versa remains unclear.

A bit of background

Historically, there has been much research illustrating a correlation between exercise and telomere length. Some studies have also demonstrated a positive relationship between mindfulness and telomeres, and there may also be a diet: telomere length link.

I am going to skip over early investigations. Let’s look at a 2017 breakthrough publication by Brigham Young University (USA) exercise scientist Larry Tucker. He studied 5,823 subjects from the US National Health and Nutrition Examination Survey (NHANES 1999–2002), ranging in age from 20 to 84. Here’s what Tucker’s analysis revealed:

Individuals who habitually exercised had much longer telomeres than did sedentary individuals. If telomere length is a valid biomarker of aging, this difference translates into nine fewer cell aging years.

Moreover, cellular aging between those defined as having high activity versus low activity also appeared significant, at 8.8 years. The corresponding advantage for those with high (compared with moderate) physical activity was 7.1 years.

The study author concluded that physical activity is significantly associated with telomere length in American men and women. Adults having higher physical activity levels tend to have longer telomeres, representing years of reduced cellular aging compared to their more sedentary counterparts.

Researchers in Finland provide some additional support. They investigated the association of physical activity intensity and volume with telomere length among elderly adults in Northern Finland. The study included 700 individuals born in 1945 in the Oulu region of the country.

The subjects all wore a wrist-based accelerometer. The participants also answered a questionnaire to assess sedentary time and get a longitudinal physical activity history and intensity. The scientists then calculated relative telomere lengths using frozen whole blood samples. Here are the results:

  • Relative telomere lengths were longer in women than men.
  • Relative telomere lengths shortened with age (for both genders).
  • The association between the total number of steps taken and relative telomere length appeared only in men. The steps taken and sedentary time significantly correlated with relative telomere lengths in 70-year-old subjects.
  • Moderate physical activity was associated with relative telomere length in subjects in the highest quartile of moderate exercise, compared to the three lower quartiles.
  • Telomere shortening may accelerate in older age.

The data is not definitive: Counterpoint

Researchers performed a comprehensive review to assess the relationship between exercise and telomere length. They pulled all relevant articles, using combinations of these search terms: telomere AND “motor activity” OR exercise OR “physical activity.” The researchers identified 37 studies, including 41,230 subjects. Here are their findings:

  • Twenty articles found no significant association.
  • Fifteen articles described a positive association.
  • Two papers discovered an inverted “U” correlation.

Still, the authors note a tendency toward demonstrating an effect of physical activity on telomere length. Unfortunately, the researchers found few prospective studies, and there were significant differences in methods between the research investigations.

One more thing: Telomere length and cardiac health

There appears to be a relationship between telomere length and heart disease. One study showed that coronary heart disease risk rises when telomeres are shorter than 200 base pairs. We do not fully understand this association, but the study authors note that shorter telomeres are associated with the rapid formation of plaques seen with atherosclerosis (a buildup of fats, cholesterol, and other materials in and on your artery walls, which can restrict blood flow. The plaque can burst, setting off a blood clot).

What you need to know

  • Telomeres are caps found at the terminal ends of our chromosomes.
  • Aging causes telomeres to shorten, resulting in gradual cell deterioration.
  • Regular physical activity reduces disease risk, possibly due to the preservation of telomeres.
  • According to one study, the longer telomeres found in more active adults may account for nine years of reduced cellular aging. Still, we do not yet have definitive evidence of the telomere length: longevity connection.

Thank you for joining me today.

References

Counterpoint: A meta-analysis

Heart disease

I have degrees from Harvard, Yale, and Penn. I am a radiation oncologist in the Seattle area. You may find me regularly posting at www.newcancerinfo.com

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