Impact of inactivity and exercise on the vasculature in humans

Abstract

The effects of inactivity and exercise training on established and novel cardiovascular risk factors are relatively modest and do not account for the impact of inactivity and exercise on vascular risk. We examine evidence that inactivity and exercise have direct effects on both vasculature function and structure in humans. Physical deconditioning is associated with enhanced vasoconstrictor tone and has profound and rapid effects on arterial remodelling in both large and smaller arteries. Evidence for an effect of deconditioning on vasodilator function is less consistent. Studies of the impact of exercise training suggest that both functional and structural remodelling adaptations occur and that the magnitude and time-course of these changes depends upon training duration and intensity and the vessel beds involved. Inactivity and exercise have direct "vascular deconditioning and conditioning" effects which likely modify cardiovascular risk.

Fig. 1

Percentage reduction in CVD events associated with physical activity that is explained by risk factors (adapted from Mora et al. 2007). Differences in risk factors explain ~59% of the relative cardiovascular risk reduction associated with exercise. This statistical modeling suggests that at least 40% of the risk reduction associated with exercise cannot be explained by established or emerging risk factors

Fig. 2

Hypothesised changes in artery function and structure (remodelling) in response to inactivity and exercise training in humans. Studies performed in both animals and humans suggest that rapid changes occur in artery function, including nitric oxide (NO) bioavailability, in response to exercise training and that these changes are superseded by arterial remodelling and normalisation of function. Physical inactivity is associated with rapid changes in arterial diameter, with structural remodelling occurring within weeks of, for example, spinal cord injury. There is little evidence for longer term vascular dysfunction in response to inactivity. Changes in artery function and structure occur rapidly in response to activity and inactivity