All‐Extremity Aerobic Exercise Training Improves Carotid Artery Compliance in Older Adults

Abstract

Advancing age is associated with decreased arterial compliance and increased arterial wall intima‐media thickness (IMT), both independent predictors of cardiovascular disease. Aerobic exercise training is a recognized strategy for reducing the risk of cardiovascular disease, however, optimal exercise prescription in older adults remains unknown. The purpose of this study was to examine the effect of all‐extremity aerobic exercise training on central and peripheral vascular structure and function in older adults. Twenty two sedentary older men and postmenopausal women (age 55 to 76 yrs, 64±1yrs; mean±SE), free of major clinical disease (e.g., diabetes, cardiovascular, renal and liver disease) were randomized to 8 weeks of all‐extremity aerobic exercise training (EX; n=12) or non‐exercise control condition (CON; n=10). Aerobic training was performed 4 days/week under supervision and consisted of 47 min of exercise on an air‐braked all‐extremity ergometer (Airdyne, Schwinn) at 70% of maximal heart rate. Central and peripheral vascular structure was assessed by measuring carotid and femoral artery diameter and IMT using high resolution ultrasonography. Vascular function was evaluated by calculating arterial compliance using simultaneous measures of diameter and pressure via applanation tonometry. In response to the exercise intervention, carotid artery compliance improved (EX: 0.12±0.01 vs. 0.14±0.02 mm2/mmHg, P=0.01 and CON: 0.12±0.02 vs. 0.12±0.02 mm2/mmHg, P=0.8; pre‐ vs. post‐intervention). However, carotid artery diameter (EX: 7.1±0.2 vs. 7.1±0.2 mm and CON: 6.8±0.2 vs. 6.8±0.2 mm; P>0.05) and IMT normalized for lumen diameter (EX: 0.09±0.005 vs. 0.08±0.003 and CON: 0.09±0.005 vs. 0.09±0.004; P>0.05) remained unchanged. Femoral artery compliance did not improve with the intervention (EX: 0.17±0.02 vs. 0.16±0.02 mm2/mmHg and CON: 0.17±0.03 vs. 0.14±0.03 mm2/mmHg; P>0.05). Similarly, femoral artery diameter (EX: 8.6±0.4 vs. 8.8±0.4 mm, and CON: 8.5±0.5 vs. 8.6±0.5 mm; P>0.05) and IMT/diameter (EX: 0.07±0.009 vs. 0.07±0.008 and CON: 0.09±0.009 vs. 0.08±0.008; P>0.05) did not change following the intervention. In conclusion, eight weeks of aerobic exercise training performed on an all‐extremity ergometer improves carotid artery compliance in healthy older adults. This finding may have important implications for reducing the risk of cardiovascular disease in older adults.