Monday, December 28, 2009

EXERCISE AND AGING

Exercise May Slow Aging at the Molecular Level. It is frequently proposed that regular physical activity can aid in prolonging the lifespan when performed at moderate levels. It is suggested this extension of life, and most importantly, total number of healthy years is due to various physiological and psychological benefits associated with routine exercise. Many individuals engage in regular training routines to suppress disease while enhancing their overall vitality and promoting longevity of their lifespan. In a current study published in the Journal of the American Heart Association, researchers investigated this topic at the molecular level. DNA telomere shortening within bodily cells is a tell-tale sign of the aging process; therefore researchers explored the consequences of physical activity on telomere biology to see if exercise may truly have an anti-aging effect. Levels of telomere-stabilizing proteins, apoptosis regulators (control the elimination of damaged or unneeded cells without negative inflammatory effects on surrounding tissues), and circulating leukocytes were examined within comparative groups of endurance athletes or sedentary humans and active or sedentary mice.

Within the subgroups where mice were examined, half were randomly selected to freely exercise on a wheel while the other half were inhibited from engaging in structured activity for a three week period. The mice that exercised presented with elevated telomerase activity in the thoracic aorta and circulating mononuclear cells (a type of macrophage), increased expression of telomere stabilizing proteins, and showed reduced expression of apoptosis regulators. This illustrates that reactive systemic dynamics from the exercise may have had a protective and anti-aging effect with relation to telomerase activity.

When the human subgroups were examined, a group of professional track-and-field athletes (mean age 20.4) and middle aged endurance runners (mean age 51.1) that had a training tenure of approximately 35 years were compared with a sedentary group of individuals of similar ages who rarely engaged in physical activity. The endurance athlete group presented with increased telomerase activity, elevated telomere-stabilizing proteins, and downregulation of apoptosis regulators when compared to the sedentary controls. The older, physically inactive controls had significantly shorter telomeres than all other participants. Furthermore, relative telomere erosion in circulating leukocytes were considerably lower in the endurance athletes who had trained for decades when compared to the sedentary controls.

“Our study population may have been too small and too young to detect subtle differences in telomere length, but the data show that beneficial anti-senescent effects of physical activity are observed more rapidly than effects on telomere length itself”, the researchers stated. The researchers also acknowledged that the possibility could not be excluded that advanced telomere shortening in the older physically inactive controls was not partly due to an unknown selection bias. Also, it could not be induced to what extent exercise’s advantageous effects on metabolism, heart rate, and blood pressure regulated telomere biology, as opposed to the physical activity itself. The researchers did claim that the observations were direct evidence that exercise does have anti-aging and prominent vasculoprotective effects. In summary, it seems that prolonged structured exercise may have a significant effect on preserving telomere length and the potential for a longer life. These findings may help to maintain the motivation to stay active now, so that one can continue to be active for many years down the road.

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