Abstract
Introduction: Physical activity (PA) has been associated with telomere shortening. The association of PA intensity or volume with telomere length (TL) is nonetheless unclear. The aim of our study was to investigate the associations of exercise intensity and volume with TL in elderly adults from Northern Finland (65° latitude North).Methods: Seven hundred elderly subjects born in 1945 in the Oulu region were investigated. PA was measured during a 2-week period with a wrist-worn accelerometer. In addition, a questionnaire was used to assess sedentary time and to achieve a longitudinal PA history and intensity. Relative telomere lengths (RTL) were determined from frozen whole blood samples using a qPCR-based method.Results: Relative telomere lengths were significantly longer in women than men and negatively correlated with age in both genders (men r = -0.210, p = 0.000, women r = -0.174, and p = 0.000). During the 2-week study period, women took more steps than men (p = 0.001), but the association between steps and RTL was only seen in men (p = 0.05). Total steps taken (r = 0.202 and p = 0.04) and sedentary time (r = -0.247 and p = 0.007) significantly correlated with RTLs in 70-year old subjects. Moderate PA was associated with RTL in subjects with the highest quartile of moderate PA compared to the three lower quartiles (p-values: 0.023 between 4th and 1st, 0.04 between 4th and 2nd, and 0.027 between 4th and 3rd) in the 70-year old subjects.Conclusion: Women had longer RTL and a higher step count compared to men. However, exercise volume and RTL correlated positively only in men. Surprisingly, age correlated negatively with RTL already within an age difference of 2 years. This suggests that telomere attrition rate may accelerate in older age. Moderate physical activity at the time of study was associated with RTL.
Highlights
Physical activity (PA) has been associated with telomere shortening
Age was negatively correlated with relative telomere length (RTL) (r = −0.185 and p = 0.0001) within the study population and the correlation was stronger in men than in women (r = −0.210 and r = −0.174, respectively) (Figure 2)
Since age was significantly associated with telomere length (TL) (Table 1), we divided the population into three groups based on age for further analysis
Summary
Physical activity (PA) has been associated with telomere shortening. The association of PA intensity or volume with telomere length (TL) is unclear. Telomeres are looped structures located at the end of chromosomes, protecting our genomic DNA from degradation. In addition to telomeric DNA, the six subunit protein complex shelterin is needed for telomere structure and function (Podlevsky and Chen, 2012). Telomerase adds TTAGGG repeats onto the chromosomal ends and is responsible for telomere length (TL). Telomerase is active in germ and stem cells, while its activity diminishes in somatic tissues, leading to telomere shortening with each cell division (Hayflick limit). At least a 400 bp of the telomeric repeat sequence is needed for maintaining a functional telomere, but experiments with cancer cell lines have demonstrated that TL less than 1 kb is sufficient to induce senescence (de Lange, 2009). Human TLs are between 10 and 15 kb at birth, and gradually decline
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