The aim of the present study was to explore the appropriate physical activity level which can improve the increased central arterial stiffness in middle-aged and elderly people. In the cross-sectional study, we evaluated common carotid arterial structures (ultrasound system and applanation tonometry) and daily physical activity energy expenditures (PAEE) corresponding to <3.0 METs (low), 3.0-5.9 METs (moderate), and ≥ 6.0 METs (high)(electronic accelerometer) in 172 people (41-82 yr). The beta-stiffness index was significantly related to age (r=0.41) and moderate, high, and total PAEE (r=-0.23~-0.18). The beta-stiffness index significantly related to moderate (r=-0.19, p<0.05) and total (r=-0.18, p<0.05) PAEE after adjustment for age and high PAEE. The betastiffness index adjusted for age and high-intensity PAEE was significantly lower in subjects engaging ≥ 30 min/day of moderate physical activity than in their sedentary peers without ≥ 30 min/day of moderate physical activity (p<0.05). In the interventional study, seventeen postmenopausal females (50~66 yr) were randomly assigned to 2 groups and underwent cycling exercise (900 kcal/week, 3-5 sessions/week, 12 weeks) either at the moderate intensity (≈4 METs; n=8) or at the high-intensity (≈7 METs; n=9). Following the training programs, the beta-stiffness index in both groups significantly decreased by 27~29% (both p<0.05). The interaction effect of time course and training intensity was not significant (p=0.97). These results suggest that regular moderateintensity activity has favorable effects on central arterial stiffness similarly to the highintensity activity in middle-aged and elderly people.

DESCENTE SPORTS SCIENCE Vol.27/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE