Aerobic Exercise Improves Microvascular Function in Older Adults

Abstract

PURPOSE: The study aimed to assess changes in microvascular function in older adults following aerobic exercise training. METHODS: Twenty five healthy, sedentary older adults (60-80 years old) participated in a 12-week randomized graded treadmill walking intervention (control (CON), n=12, 66±4 yrs, BMI=30±5; exercise (EX), n=13, 68±6 yrs, BMI=29±5). MRI measured blood-oxygen-level dependent (BOLD) responses of the calf were used to evaluate microvascular function; brief (1s) maximal plantar flexion contractions were performed. Blood flow in the popliteal artery was measured by ultrasound following brief maximal contractions to evaluate small vessel vasodilation in the calf. In addition, muscle oxidative capacity was assessed with 31P MRS following 30-s of plantar flexion. Repeated measures ANOVA was used to assess differences between groups with significance at p <0.05. RESULTS: Peak post-contraction BOLD response in the soleus increased by ~30% in EX (PRE= 103.5±1.4%, POST=104.5±1.6%) compared to CON (PRE: 103.6±1.9%, POST: 103.6±1.7%), p<0.05. Peak post-contraction blood flow in the popliteal artery increased by 20% in EX (PRE: 248±76.8 ml/min, POST: 298±103.9 ml/min) compared to control (PRE: 251±88 ml/min, POST: 259±80 ml/min), p<0.05. Muscle oxidative capacity (tau,s) of the plantar flexors improved by 34% (PRE: 40.2±14.0s, POST: 30.1±10.6s, p<0.05) compared to CON (PRE: 35.4±6.6s, POST: 34.7±9.4s), p<.0.05. CONCLUSION: Aerobic exercise significantly improved BOLD microvascular responses in the soleus of older adults. In addition, peak flow following brief contraction was also improved suggesting increased small vessel vasodilation of the calf. Supported by NIH AG042041.