Less Exercise but Greater Arterial Stiffness Response

Abstract

PURPOSE: To examine the impact of rest interval duration of low-intensity accumulated cycling on arterial stiffness in humans, and compare this impact to that of moderate-intensity continuous cycling. METHODS: Sixteen healthy recreational active young men (20.5±0.4 years) underwent non-cycling control (CON), moderate-intensity continuous cycling in the form of 1×30 min (MC), low-intensity accumulated cycling in the form of 2×15 min with 20-min (LA20) and 10-min rest interval trial (LA10). Cycling intensity was 50% heart rate reserve in MC trial, and 35% heart rate reserve in LA10 and LA20 trials. Arterial stiffness in cardio-ankle vascular index (CAVI) was measured at baseline (BL), immediately after (0 min) and 60 min after exercise. CAVI change from baseline in the same trial ( CAVI) was used for analysis. RESULTS: There were no significant CAVI changes with time in CON trial (0.0±0.0, 0.0±0.1 and 0.0±0.1 at BL, 0 min and 60 min, respectively). In MC and LA20 trial, CAVI demonstrated similar changes with time (0.0±0.0, -1.1±0.1 and -0.1±0.1 in MC trial, and 0.0±0.0, -0.7±0.2 and 0.0±0.2 at BL, 0 min and 60 min in LA20 trial). However, CAVI in LA10 trial decreased to -1.0±0.1 at 0 min, and reverted to -0.5±0.1 at 60 min, remaining significantly lower than that in CON trial (0.0±0.1, P< 0.001) and MC trial (-0.1±0.1P< 0.01) at 60 min. CONCLUSION: Arterial stiffness improvement induced by accumulated cycling was influenced by interval duration between bouts. Low-intensity accumulated cycling, when with a shorter rest interval, may result in greater arterial stiffness improvement than moderate-intensity continuous cycling. Supported by National Natural Science Foundation of China (31371206).