Acute effects of continuous and interval low-intensity exercise on arterial stiffness in healthy young men

Abstract

To examine and compare systemic arterial stiffness responses in humans to acute continuous and interval low-intensity exercise. Fifteen healthy young men (21.2±0.4years) underwent non-exercise control (CON), continuous exercise (CE), and interval exercise trial (IE) in a randomized balanced self-control crossover design. Systemic arterial stiffness (Cardio-ankle vascular index, CAVI) was measured at baseline (BL), immediately after (0min) and 40min after exercise in CE and IE trials, and at corresponding time points in CON trial. Subjects cycled continuously for 30min at 35% heart rate reserve after BL measurement in CE trial, whereas in IE trial, subjects cycled two bouts of 15-min separated by a 20-min rest at the same intensity. There were no significant CAVI changes with time in CON trial (6.7±0.1, 6.7±0.1, 6.6±0.1 at BL, 0 and 40min, respectively). In CE trial, CAVI decreased immediately after exercise (0min) and returned to baseline after 40min of recovery (6.5±0.1, 5.5±0.2, 6.4±0.1 at BL, 0 and 40min, respectively). IE elicited similar CAVI reduction from 6.7±0.1 at baseline to 5.6±0.2 at 0min: however, CAVI at 40min remained significantly low compared to that of CON trial at corresponding time point (6.0±0.1 vs. 6.6±0.1, P<0.001). Both acute continuous and interval low-intensity exercise elicits transient improvement in systemic arterial stiffness in humans. Despite equivalent exercise intensity and duration, interval exercise resulted in improved arterial stiffness for longer duration.