(January 28, 2008 - Insidermedicine) Level of physical activity during leisure time is linked with biological markers of aging in research published in the Archives of Internal Medicine.

Here are some facts about the health benefits of physical activity to share with patients:

•    Physical activity, in combination with reduced caloric intake, can contribute to weight reduction, which in turn has been shown to reduce the risk of diabetes and decrease insulin resistance as well as to improve measures of glycemia and dyslipidemia in patients with diabetes.

•    Prospective epidemiological studies have shown that higher levels of physical activity are associated with a lower incidence of coronary artery disease and stroke. In addition, physical inactivity is recognized as an important risk factor for cardiovascular disease.

•    Moderate to vigorous activity for at least 45 minutes on five or more days per week may help reduce the risk of breast and colon cancers and also may reduce the risk of kidney, endometrial, and esophageal cancers.

Researchers from King’s College London administered questionnaires about physical activity level, smoking habits, and socioeconomic status to over 2,400 Caucasian twins. They also took blood samples to measure telomere length in the participants' leukocytes. Leukocytes telomeres are known to shorten with time and thus serve as markers of biological age.

Older patients had shorter telomeres, with an average loss of 21 nucleotides per year. Participants who were less physically active during their leisure time had shorter telomeres than those who were more active, even after adjusting for BMI, smoking habits, socioeconomic status, and physical activity during working hours. In fact, the mean difference in telomere length between the most active, who averaged nearly 200 minutes of physical activity per week, and the least active, who averaged under 16 minutes of physical activity per week, was 200 nucleotides. That translates to a biological age difference of about ten years.

Based on these findings, the authors conclude that lower physical activity level during leisure time is linked with older biological age. They suggest that physical activity may reduce stress, which is known to contribute to aging.

For Insidermedicine in Depth, I'm Essie Heinrich.