- According to a study of more than 400,000 participants, walking pace is associated with telomere length, a genetic marker of biological age.
- Among the participants, aged 56.5 years on average, those who walked the fastest had telomeres whose length was equivalent to a biological age 16 years younger.
- This association depended on the intensity of walking (speed) and not on the total amount of physical activity.
Telomeres are repetitive DNA structures found at both ends of chromosomes that ensure the integrity of the genome during cell division (see also our article on the subject). Each time a cell divides, the telomeres shorten, until they become too short and the cell can no longer divide; it becomes senescent and eventually dies. The accumulation of senescent cells in the organs of the human body contributes to the development of diseases related to aging and frailty. Researchers consider telomere length to be a marker of “biological age”, independent of an individual’s date of birth.
The benefits of walking on physical and mental health are well documented, but researchers wanted to know if brisk walking could also be associated with slowing biological aging, as estimated by telomere length. In the UK study, 405,981 participants with an average age of 56.5 years reported information on walking speed, either by self-report or by wearing an accelerometer-type recording device. Telomere length was assessed in leukocytes (white blood cells) by PCR from a blood sample from each of the participants. The results show that faster walking speed was associated with longer telomeres (younger biological age) regardless of the total amount of physical activity. Complex statistical analyses (bidirectional Mendelian randomization) suggest a causal link between walking speed and telomere length, but not the reverse, i.e., that the lengthening of the telomeres is not responsible for a greater walking speed. A causal link can only be established with certainty by well-controlled and well-conducted intervention studies.
The results of this study reinforce the importance of brisk walking for the maintenance of good health. An earlier study by the same researchers at the University of Leicester in the UK indicated that as little as 10 minutes of brisk walking was associated with longer life expectancy, up to 20 years longer when comparing fast walkers to slow walkers. Brisk walking can be done at any age, indoors or outdoors, and requires no special athletic skills or expensive equipment.