Influence of altered physical activity on vascular function in older adults: A divergent impact on the conduit and microvascular systems

Abstract

Aging is associated with a progressive decline in physiological and functional reserve capacity in humans. The rate of this decline is accelerated by periods of reduced activity. Prolonged reductions in physical activity (i.e. weeks) are commonly incurred with age‐related insults (i.e., hospitalization, injury, illness) in older adults. The effect of these periods of reduced activity on vascular function reserve remains to be determined. Any detrimental effects of this reduced activity on vascular function are clinically relevant, as this would pose an increased risk for adverse cardiovascular events. Furthermore, it remains to be determined if any detrimental effect on vascular function incurred during prolonged reduced activity is reversible with resumption of normal activity. Therefore, the purpose of the current study was to investigate the effects of prolonged reductions in physical activity, followed by a return to normal activity, on leg vascular function in older adults. Popliteal artery flow‐mediated dilation (FMD) and reactive hyperemia were measured at baseline, following 14 days of reduced activity (i.e. 70% reduction in steps per day), and 14 days after returning to normal activity in 5 healthy older subjects (2 men and 3 women, age: 70 ± 8 yrs, stature: 164 ± 13 cm; body mass, 69 ± 10 kg). The steps per day during the reduced activity period (3,212 ± 1,673 steps) were significantly lower than both baseline (11,007 ± 2,417 steps) and return to normal activity (10,068 ± 1,357 steps), while baseline and return to normal activity were not significantly different (p = 0.29). Popliteal artery FMD was significantly attenuated following reduced activity and returned to baseline after 2 weeks of normal activity (Figure 1A). There were no significant differences between conditions in popliteal artery shear rate (p = 0.43). The popliteal artery reactive hyperemia was not significantly different between conditions (p = 0.70, Figure 1B). Therefore, a prolonged, 14 day, alteration in physical activity in older adults directly influences leg conduit artery vascular function (i.e. FMD), while leg microvascular function (i.e. reactive hyperemia) remains unaltered. These results document the influence of alterations in physical activity on cardiovascular health in older adults, but also highlight a divergent impact on the conduit and microvascular systemsThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.