Purpose-The purpose of this study was to examine the relationship of exercise energy expenditure (EEE) with both telomere length and telomerase activity in addition to accounting for hTERT C-1327T promoter genotype.Methods-Sixty-nine (n = 34 males; n = 35 females) participants 50-70 yr were assessed for weekly EEE level using the Yale Physical Activity Survey. Lifetime consistency of EEE was also determined. Subjects were recruited across a large range of EEE levels and separated into quartiles: 0-990, 991-2340, 2341-3540, and 93541 kcalIwk j1 . Relative telomere length and telomerase activity were measured in peripheral blood mononuclear cells (PBMC).Results-The second EEE quartile exhibited significantly longer telomere lengths [1.12 T 0.03 relative units (RU)] than both the first and fourth EEE quartiles (0.94 T 0.03 and 0.96 T 0.03 RU, respectively; P G 0.05) but was not different from the third quartile. Telomerase activity was not different among the EEE quartiles. An association was observed between telomerase enzyme activity and hTERT genotype with the TT genotype (1.0 • 10 j2 T 4.0 • 10 j3 attomoles (amol) per 10,000 cells; n = 19) having significantly greater telomerase enzyme activity than both the CT (1.3 • 10 j3 T 3.2 • 10 j3 ; n = 30) and CC groups (5.0 • 10 j4 T 3.9 • 10 j3 ; n = 20; P = 0.01).Conclusion-These results indicate that moderate physical activity levels may provide a protective effect on PBMC telomere length compared with both low and high EEE levels.
Keywords
TELOMERE BIOLOGY; EXERCISE ENERGY EXPENDITURE; hTERT GENOTYPE; GENETICS; DNAPhysical activity (PA) and increased physical fitness are known to decrease the likelihood of morbidity and mortality from a variety of causes (e.g., reduced cardiovascular disease (CVD), insulin resistance, and hypertension) (6), with concomitant increases in longevity (21). Whereas the reduction of disease end points will necessarily increase longevity, whether PA also directly affects cellular aging remains unclear for either rodents or humans (7). Telomere length is a primary biomarker of cellular aging that has recently been associated with CVD (1), insulin resistance and hypertension (14), and morbidity and mortality (9). In the present study, we explored the correlation of PA levels with telomere length and telomerase enzyme activity.Address for correspondence: Stephen M. Roth, Ph.D., 2134 SPH Bldg, Department of Kinesiology, University of Maryland, College Park, MD 20742-2611; E-mail: sroth1@umd.edu.. Telomeres are found on the ends of linear chromosomes and act as a mitotic clock (18), which shortens with every cell division until cellular senescence. Thus, telomeres are considered an important aging biomarker (2,4). Telomeres and their length are not, however, static entities but rather are a dynamic system (4). In certain cells, the ribonucleoprotein, telomerase, maintains and lengthens telomeres, allowing continued mitotic activity without progression to senescence (5). In cells with telomerase activity, telomere length can be maintain...
