Respiratory fitness, free living physical activity, and cardiovascular disease risk in older individuals: A doubly labeled water study

The objective of this study was to examine the importance of cardiorespirat ory fitness vs, physical activity energy expenditure on selected cardiovasc ular disease risk factors in older individuals. One hundred and seventeen o lder individuals, 53 men (68 +/- 9 yr) and 63 women (67 +/- 7 yr), particip ated in the study. This cohort was divided into 4 groups: 1) high cardiores piratory fitness and high physical activity, 2) high cardiorespiratory fitn ess and low physical activity, 3) low cardiorespiratory fitness and high ph ysical activity, and 4) low cardiorespiratory fitness and low physical acti vity. Cardiorespiratory fitness (VO2max) was determined from a graded exerc ise test, physical activity energy expenditure was measured by doubly label ed water and indirect calorimetry, body composition was determined by dual energy x-ray absorptiometry, and dietary practices were determined by a 3-d ay recall. Cardiorespiratory fitness exerted greater effects on the cardiov ascular disease risk profile than physical activity. That is, older individ uals with higher levels of cardiorespiratory fitness, regardless of their p hysical activity levels, showed lower levels of fasting insulin (P < 0.01), triglycerides (P < 0.05), total cholesterol (P < 0.05), total to high dens ity lipoprotein cholesterol ratio (P < 0.05), low density lipoprotein (P < 0.05), and lower waist circumference (P < 0.01), Moreover, individuals with a high cardiorespiratory fitness but low physical activity energy expendit ure displayed a more favorable cardiovascular disease risk profile than ind ividuals with low cardiorespiratory fitness and high physical activity ener gy expenditure. The results suggest that higher levels of cardiorespiratory fitness have greater cardioprotective effects than higher levels of free l iving physical activity in older individuals. Although these findings do no t discount the health benefits of being physically active, it is possible t hat greater emphasis should be placed on aerobic exercise to increase cardi orespiratory fitness in the elderly.