Effect of high-intensity training on endothelial function in patients with cardiovascular and cerebrovascular disease: A systematic review

Abstract

Objectives: Exercise improves endothelial dysfunction, the key manifestation of cardiovascular and cerebrovascular disease, and is recommended in both cardiovascular and cerebrovascular rehabilitation. Disagreement remains, however, on the role of intensity of exercise. The purpose of this review was to gather current knowledge on the effects of high-intensity training versus moderate-intensity continuous exercise on endothelial function in cardiovascular and cerebrovascular patients.

Methods: A systematic review was performed in PubMed database, Embase and Cochrane libraries and on PEDro using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were restricted to cardiovascular and cerebrovascular patients, and healthy subjects as general reference. Interventions comprised of high-intensity training alone, high-intensity training compared to moderate-intensity continuous exercise, or no training, with endothelial function as outcome measure. Endothelial function was measured either physiologically by flow-mediated dilatation and/or by systemic biomarkers. Data were analyzed descriptively due to non-comparability for a meta-analysis to be performed.

Results: A total of 20 studies were included in the review. Although there was great heterogenecity in design, population and exercise protocols, all studies found high-intensity training to be safe. High-intensity training was equal to moderate-intensity continuous exercise through improvement in endothelial function in 15 of the 20 selected studies, as measured by flow-mediated dilatation, nitric oxide bioavailability and circulating biomarkers. Only a few studies examined high-intensity training in cerebrovascular patients, none with endothelial function as outcome.

Conclusion: High-intensity training is promising as a time-efficient exercise strategy in cardiovascular rehabilitation, but data on endothelial effects in cerebrovascular rehabilitation are warranted. Agreement on a more uniform exercise protocol is essential to further investigate the optimal exercise mode for cerebrovascular rehabilitation.

Keywords: Vascular endothelium; aerobic exercise; endothelial function; flow-mediated dilatation; high-intensity exercise; high-intensity training; interval training.

Figure 1.

The general effects of exercise. The effect of exercise targets various organ systems thus improving cardiovascular, endothelial, cerebral and metabolic function, all parameters important to improve rehabilitation and reduce stroke risk. The figure depicts the various physiological systems affected. Increased flow in the vessels induced by exercise activates endothelial mechanoreceptors initiating synthesis of nitric oxide (NO) through activation of endothelial nitric oxide synthase (eNOS). Nitric oxide release is involved in both processes of vasodilation and inflammation. Dysfunction of the endothelium increases risk of platelet aggregation and leukocyte infiltration through adhesion molecules. Furthermore, exercise improving muscle and cardiac function improves the metabolism of glucose and cholesterol. Illustration is created with inspiration from Schmidt et al.

Figure 2.

Flow diagram of selection process.