title: Relationship between physical activity level, telomere length, and telomerase activity.
abstract: OBJECTIVE
  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 >3541 kcal x wk(-1). 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 +/- 0.03 relative units (RU)] than both the first and fourth EEE quartiles (0.94 +/- 0.03 and 0.96 +/- 0.03 RU, respectively; P < 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 x 10(-2) +/- 4.0 x 10(-3) attomoles (amol) per 10,000 cells; n = 19) having significantly greater telomerase enzyme activity than both the CT (1.3 x 10(-3) +/- 3.2 x 10(-3); n = 30) and CC groups (5.0 x 10(-4) +/- 3.9 x 10(-3); n = 20; P = 0.01).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Kinesiology, School of Public Health, University of Maryland, College Park, MD 20742-2611, USA.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Ludlow
authors.forename: Jo B
authors.initials: JB
authors.lastname: Zimmerman
authors.forename: Sarah
authors.initials: S
authors.lastname: Witkowski
authors.forename: Joe W
authors.initials: JW
authors.lastname: Hearn
authors.forename: Bradley D
authors.initials: BD
authors.lastname: Hatfield
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Roth
mesh_terms: D000368:Aged; D001483:Base Sequence; D017931:DNA Primers; D015444:Exercise; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013315:Stress, Psychological; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*; D016615:Telomere
chemical_list: D017931:DNA Primers; C509186:TERT protein, human; D019098:Telomerase
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