Telomeres of runners

The relationship between walking speed and telomere length has been confirmed

Maria Azarova, Naked Science

Researchers from the University of Leicester and Leicester General Hospital (UK) studied the data of 405,981 people stored in the British Biobank and confirmed that a faster pace of walking, regardless of the overall level of physical activity, is associated with the length of telomeres — the end sections of chromosomes, considered a marker of biological age. The results of the work are published in the journal Communications Biology (Dempsey et al., Investigation of a UK biobank cohort reveals causal associations of self-reported walking pace with telomere length).

Walking is a simple and affordable form of physical exercise for people of any age. Scientists have long stated that walking is not only generally useful, but also reduces the risk of cardiovascular diseases and mortality from all causes, and if you walk at a faster pace every day, you can even increase life expectancy. However, it was not fully understood how walking speed is related to indicators of biological age, reflecting the degree of development and maturity of the organism.

Telomeres are a complex of telomeric DNA and related proteins, they protect the ends of chromosomes from degradation, fusion and abnormal recombination of DNA strands. Telomeric regions gradually shorten with each cell division, contributing to replicative, or cellular aging (due to the loss of the cell's ability to divide). In addition, telomere shortening is regulated by factors such as oxidative stress and inflammation. 

As the authors of previous studies suggested, there is a link between a high level of physical activity and endurance with longer end sections of chromosomes: consequently, physical exertion through telomere elongation helps to slow down biological aging. But, according to scientists from Leicester, most of the works on this topic, in which people participated, were small and did not fully consider the causal relationship between simple types of physical exertion like walking and telomere length.

The average age of the participants of the British Biobank, the genetic information from which formed the basis of the new study, was 56.5 years, the body mass index was 27.2, 54% were women, 95% were white. Approximately half of the participants (212,303 people, 52.3%) reported that they walk "at an average speed", 6.6% (26,835) — slowly, 41.1% (166,843) — at a fast pace. Compared to those who are not in a hurry, people from the first and third groups were slightly younger, were more likely to have never smoked and were less likely to take medications to lower cholesterol or blood pressure, were less likely to have chronic diseases or were restricted in movement. Among the "slow", those suffering from obesity and a tendency to drink alcohol were more common.

"Those who walk at an average or fast pace had significantly longer telomeres than those who walk slowly," the researchers wrote. A secondary analysis, which took into account data from the accelerometer, showed that if you perform most of your daily physical activity with a higher intensity, the end sections of the chromosomes will be longer. The connection was maintained even after taking into account other factors.

"We found evidence that walking pace has a causal relationship with telomere length. Depending on the simulated difference in walking pace (from slow to medium or from medium to fast), there was an increase in the standard deviation of telomere length by 0.192 and 0.226 before and after taking into account the body mass index, respectively," the scientists add. According to their calculations, the difference in biological age between fast-walking and slow-walking is 16 years, although an adjusted analysis gives a difference of two years.

In the future, the researchers plan to confirm whether behavioral interventions aimed at increasing walking speed or increasing the intensity of physical activity can slow down the degradation of telomeres. 

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