Accelerometer-based measures of sedentary behavior and cardio-metabolic risk in active older adults

Sedentary behavior has been proposed as an independent cardio-metabolic risk factor even in adults who are physically active through recreational activity. Because little is known about the metabolic effects of sedentariness in seniors, the relationship between sedentary behavior and cardio-metabolic risk was examined in physically active older adults.

Fifty-four community dwelling men and women > 65 years of age (mean 71.5 years) were enrolled in this cross-sectional observational study. Subjects were in good health and free of known diabetes. Activity levels (sedentary, light, moderate to vigorous activity time per day) were recorded with accelerometers worn continuously for 7 days. Cardio-metabolic risk factors measured consisted of the American Heart Association diagnostic criteria for metabolic syndrome (waist circumference, triglycerides, high-density lipoprotein, systolic blood pressure and fasting glucose) as well as low-density lipoprotein (LDL). The relationships between activity measures and cardio-metabolic risk factors were examined. Significant variables were then entered into a stepwise multivariate regression model.

All but one subject achieved exercise levels recommended by the American College of Sports Medicine. The average proportion of time spent at a sedentary activity level each day was 72.7%. From the regression analysis, the only significant association found between cardio-metabolic risk outcomes and activity predictors was between LDL and sedentary time, with LDL detrimentally associated with average sedentary time per day (Standardized Beta Correlation Coefficient 0.302, p < 0.05).

Sedentary behavior is associated with an adverse metabolic effect on LDL in seniors, even those who meet guideline recommendations for an active "fit" adult.