Women who are physically active during their leisure time appear to be biologically younger than those with sedentary lifestyles, according to a new study in the Archives of Internal Medicine.
The researchers involved said that regular exercisers had lower rates of cardiovascular disease, type 2 diabetes, cancer, high blood pressure, obesity and osteoporosis. "A sedentary lifestyle increases the propensity to aging-related disease and premature death," the study notes. "Inactivity may diminish life expectancy not only by predisposing to aging-related diseases but also because it may influence the aging process itself."
To arrive at their findings, the researchers examined the length of telomeres — repeated sequences at the end of chromosomes — in white blood cells (leukocytes). Leukocyte telomeres progressively shorten over time and serve as a marker of biological age.
They found that women who were less physically active in their leisure time had shorter leukocyte telomeres than those who were more active. "Such a relationship between leukocyte telomere length and physical activity level remained significant after adjustment for body mass index, smoking, socioeconomic status and physical activity at work," the researchers said. "The mean difference in leukocyte telomere length between the most active [who performed an average of 199 minutes of physical activity per week] and least active [16 minutes of physical activity per week] subjects was 200 nucleotides, which means that the most active subjects had telomeres the same length as sedentary individuals up to 10 years younger, on average."
The study speculates that oxidative stress — damage caused to cells by exposure to oxygen — and inflammation are likely mechanisms by which sedentary lifestyles shorten telomeres. In addition, perceived stress levels have been linked to telomere length. Physical activity may reduce psychological stress, thus mitigating its effect on telomeres and the aging process.
"The U.S. guidelines recommend that 30 minutes of moderate-intensity physical activity at least five days a week can have significant health benefits," the authors write. "Our results underscore the vital importance of these guidelines. They show that adults who partake in regular physical activity are biologically younger than sedentary individuals. This conclusion provides a powerful message that could be used by clinicians to promote the potential anti-aging effect of regular exercise."
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Source: American Medical Association