Vascular adaptation to exercise in humans: Role of hemodynamic stimuli

On the 400th anniversary of Harvey’s Lumleian lectures, this review focuses on “hemodynamic” forces associated with the movement of blood through arteries in humans and the functional and structural adaptations that result from repeated episodic exposure to such stimuli. The late 20th century discovery that endothelial cells modify arterial tone via paracrine transduction provoked studies exploring the direct mechanical effects of blood flow and pressure on vascular function and adaptation in vivo. In this review, we address the impact of distinct hemodynamic signals that occur in response to exercise, the interrelationships between these signals, the nature of the adaptive responses that manifest under different physiological conditions, and the implications for human health. Exercise modifies blood flow, luminal shear stress, arterial pressure, and tangential wall stress, all of which can transduce changes in arterial function, diameter, and wall thickness. There are important clinical implications of the adaptation that occurs as a consequence of repeated hemodynamic stimulation associated with exercise training in humans, including impacts on atherosclerotic risk in conduit arteries, the control of blood pressure in resistance vessels, oxygen delivery and diffusion, and microvascular health. Exercise training studies have demonstrated that direct hemodynamic impacts on the health of the artery wall contribute to the well-established decrease in cardiovascular risk attributed to physical activity. © 2017 the American Physiological Society

Sprint interval and sprint continuous training increases circulating CD34+ cells and cardio-respiratory fitness in young healthy women

The improvement of vascular health in the exercising limb can be attained by sprint interval training (SIT). However, the effects on systemic vascular function and on circulating angiogenic cells (CACs) which may contribute to endothelial repair have not been investigated. Additionally, a comparison between SIT and sprint continuous training (SCT) which is less time committing has not been made

Effects of acute exercise on endothelial function in abdominal aortic aneurysm patients.

Endothelial dysfunction is observed in patients with abdominal aortic aneurysm (AAA), who have increased risk of cardiovascular events and mortality. This study aimed to assess the acute effects of moderate and higher-intensity exercise on endothelial function, as assessed by flow-mediated-dilation (FMD), in AAA patients (n=22; 74±6 y) and healthy adults (n=22; 72±5y). Participants undertook three randomised visits, including moderate-intensity continuous exercise (40% peak power output, PPO), higher-intensity interval exercise (70% PPO), and a no-exercise control. Brachial artery FMD was assessed at baseline, 10- and 60-min after each condition. Baseline FMD was lower in AAA patients compared to healthy adults [by 1.10%, (95% CI, 0.72 to 1.81), P=0.044]. There were no group differences in the FMD responses after each condition (P=0.397). FMD did not change after the control condition, but increased by 1.21% (95% CI, 0.69 to 1.73, P<0.001) 10 min after moderate-intensity continuous exercise in both groups, and returned to baseline levels after 60-min. Conversely, FMD decreased by 0.93% (95% CI, 0.41 to 1.44, P<0.001) 10-min after higher-intensity interval exercise in both groups, and remained decreased after 60 min. This study found that the acute response of endothelial function to exercise is intensity-dependent and similar between AAA patients and healthy adults. This provides evidence that regular exercise may improve vascular function in AAA, as it does in healthy adults. Improved FMD following moderate-intensity exercise may provide short-term benefit. Whether the decrease in FMD following higher-intensity exercise represents additional risk and/or a greater stimulus for vascular adaptation remains to be elucidated

Combined aerobic and resistance exercise training decreases peripheral but not central artery wall thickness in subjects with type 2 diabetes

Objective Little is known about the impact of exercise training on conduit artery wall thickness in type 2 diabetes. We examined the local and systemic impact of exercise training on superficial femoral (SFA), brachial (BA), and carotid artery (CA) wall thickness in type 2 diabetes patients and controls. Methods Twenty patients with type 2 diabetes and 10 age- and sex-matched controls performed an 8-week training study involving lower limb-based combined aerobic and resistance exercise training. We examined the SFA to study the local effect of exercise, and also the systemic impact of lower limb-based exercise training on peripheral (i.e. BA) and central (i.e. CA) arteries. Wall thickness (WT), diameter and wall:lumen(W:L)-ratios were examined using automated edge detection of ultrasound images. Results Exercise training did not alter SFA or CA diameter in type 2 diabetes or controls (all P > 0.05). BA diameter was increased after training in type 2 diabetes, but not in controls. Exercise training decreased WT and W:L ratio in the SFA and BA, but not in CA in type 2 diabetes. Training did not alter WT or W:L ratio in controls (P > 0.05). Conclusion Lower limb-dominant exercise training causes remodelling of peripheral arteries, supplying active and inactive vascular beds, but not central arteries in type 2 diabetes

Potential cellular and biochemical mechanisms of exercise and physical activity on the ageing process

Exercise in young adults has been consistently shown to improve various aspects of physiological and psychological health but we are now realising the potential benefits of exercise with advancing age. Specifically, exercise improves cardiovascular, musculoskeletal, and metabolic health through reductions in oxidative stress, chronic low-grade inflammation and modulating cellular processes within a variety of tissues. In this this chapter we will discuss the effects of acute and chronic exercise on these processes and conditions in an ageing population, and how physical activity affects our vasculature, skeletal muscle function, our immune system, and cardiometabolic risk in older adults

Efficacy of interval exercise training to improve vascular health in sedentary postmenopausal females.

Background Menopause represents a turning point where vascular damage begins to outweigh reparative processes, leading to increased cardiovascular disease (CVD) risk. Exercise training reduces CVD risk in postmenopausal females via improvements in traditional risk factors and direct changes to the vasculature. We assessed the effect of moderate (MODERATE-IT) versus heavy (HEAVY-IT) intensity interval exercise training upon markers of cardiovascular health and vascular repair in postmenopausal females. Methods Twenty-seven healthy postmenopausal females (56 ± 4 yr) were assigned to 12 weeks of either MODERATE-IT or HEAVY-IT, twice per week. MODERATE-IT consisted of 10s work, and 10s active recovery repeated for 30 min. HEAVY-IT comprised 30s work, and 30s active recovery repeated for 21 ± 2 min. Endothelial function (flow-mediated dilation), arterial stiffness (pulse wave velocity), and V̇O2peak were assessed pre-training and post-training. Blood samples were obtained pre-training and post-training for enumeration of circulating angiogenic cells (CACs), culture of CACs, and lipoprotein profile. Results V̇O2peak increased 2.4 ± 2.8 ml/kg/min following HEAVY-IT only (p  0.05). Peripheral pulse wave velocity reduced 8% with exercise training, irrespective of intensity (p  0.05). CAC adhesion to vascular smooth muscle cells (VSMC) increased 30 min post plating following MODERATE-IT only (p < 0.05). Conclusions HEAVY-IT was more effective at increasing V̇O2peak in postmenopausal females. The ability of CACs to adhere to VSMC improved following MODERATE-IT but not HEAVY-IT. Interval training had the same effect on endothelial function (no change) and arterial stiffness (reduced), regardless of exercise intensity