Physiological effects of exercise in patients with peripheral vascular disease

This work sought to identify physiological effects of aerobic exercise training in patients with lower-limb vascular disease.

The main aim of the studies in Section 1 of this thesis was to investigate potential mechanisms by which arm-crank exercise training evokes improved walking performance in patients with intermittent claudication. In Study 1, multiple regression analysis was used to identify key physiological predictors of walking performance in this patient group. The three variables included in the final regression model were peak oxygen uptake, calf muscle oxygenation at 1 min and time-to-minimum calf muscle oxygenation. The results suggest that cardiopulmonary fitness and the ability to match oxygen delivery to metabolic demand are important determinants of walking performance in claudicants. In Study 2, a randomised, controlled trial investigated limb specific and cross-transfer effects of arm-crank exercise training in claudicants. After 12 weeks of training, patients showed improvements in walking performance and specific cardiopulmonary fitness and calf muscle oxygenation variables. The results suggest that the improvement in walking performance is attributable, at least in part, to improved lower-limb oxygen delivery.

The main aims of the studies in Section 2 of this thesis were to compare cutaneous microvascular function between post-surgical varicose-vein patients and age-matched healthy controls and to investigate whether or not any impairment of function is alleviated by acute and chronic lower-limb exercise. The results suggest that postsurgical varicose-vein patients have microvascular endothelial dysfunction that can be corrected both by acute and chronic moderate-intensity lower-limb exercise. Attenuation of microvascular abnormalities might be important for reducing the risk of venous ulceration in this patient group.

Collectively, this thesis provides evidence that aerobic exercise training is an effective stimulus for evoking favourable physiological adaptations in patients with lower-limb vascular disease. Therefore, aerobic exercise training can generally be considered a useful adjunct therapy for these patients.