If you are physically very active, the chances are your genetic material is ten years younger than it would be if you spent your life as a couch potato, researchers at King’s College London conclude in the Archives of Internal Medicine. The British researchers measured the length of the telomeres in 2400 twins for whom they had determined how much physical activity they had had in the previous year.
The longer your telomeres, the more time your genetic material still has to go. A number of studies have been published recently claiming that telomeres are longer in people who consume more vitamin D, do strength sports or are higher up the social scale.
The researchers measured the length of the telomeres in the DNA of white blood cells of the twins. The researchers divided the twins into four groups according to the amount of physical activity they had: inactive [16 minutes of physical activity per day], light activity [36 minutes of physical activity per day], moderate activity [102 minutes of physical activity per day] and heavy activity [199 minutes of physical activity per day].
The researchers did not take into account physical activity in the workplace. They only looked at how much physical activity the twins had in their free time.
The figure below shows the relationship between the amount of physical activity and telomere length.
As you can see, the researchers corrected for bodyweight, smoking and social environment [SES = socio economic score]. The researchers did so because there are studies that indicate that smoking and overweight accelerate the erosion of telomeres [Lancet. 2005 Aug 20-26;366(9486):662-4.], as does chronic stress [Proc Natl Acad Sci U S A. 2004 Dec 7;101(49):17312-5.].
The length of the telomeres in blood cells is also genetically determined. Some studies suggest that heredity determines the length for almost eighty percent. If you look at the effect of physical activity on telomere length in this light, then it would seem that physical activity is not an important factor. This is not the case, according to the researchers: they say physical activity reduces genetic aging by ten years.
The association between physical activity in leisure time and leukocyte telomere length.
Physical inactivity is an important risk factor for many aging-related diseases. Leukocyte telomere dynamics (telomere length and age-dependent attrition rate) are ostensibly a biological indicator of human aging. We therefore tested the hypothesis that physical activity level in leisure time (over the past 12 months) is associated with leukocyte telomere length (LTL) in normal healthy volunteers.
We studied 2401 white twin volunteers, comprising 2152 women and 249 men, with questionnaires on physical activity level, smoking status, and socioeconomic status. Leukocyte telomere length was derived from the mean terminal restriction fragment length and adjusted for age and other potential confounders.
Leukocyte telomere length was positively associated with increasing physical activity level in leisure time (P< .001); this association remained significant after adjustment for age, sex, body mass index, smoking, socioeconomic status, and physical activity at work. The LTLs of the most active subjects were 200 nucleotides longer than those of the least active subjects (7.1 and 6.9 kilobases, respectively; P= .006). This finding was confirmed in a small group of twin pairs discordant for physical activity level (on average, the LTL of more active twins was 88 nucleotides longer than that of less active twins; P= .03).
A sedentary lifestyle (in addition to smoking, high body mass index, and low socioeconomic status) has an effect on LTL and may accelerate the aging process. This provides a powerful message that could be used by clinicians to promote the potentially antiaging effect of regular exercise.
PMID: 18227361 [PubMed - indexed for MEDLINE]