Abstract 18802: Short Periods of High-intensity Intermittent Exercise Decreases Arterial Stiffness via Upregulation of Endothelial Nitric Oxide Signalling
Introduction: Aerobic exercise and short periods of high-intensity intermittent exercise training (HIIT) induce improvement of arterial stiffness, whereas resistance training induces no change or deterioration of arterial stiffness. Release of endothelium-derived nitric oxide (NO) in response to aerobic exercise contributes to exercise-induced vasodilation, resulting in the reduction in arterial stiffness. However, the short periods of HIIT on endothelial NO production remain unclear.
Purpose: This study aimed to clarify the effects of short periods of HIIT on arterial stiffness and endothelial NO production in rats.
Methods: Forty male Sprague-Dawley rats were randomly divided into 4groups; CON: sedentary control, AT: aerobic exercise training (treadmill running for 60min at 30m/min, 5days/wk for 8weeks from 10-week-old), HIIT: short periods of high-intensity intermittent exercise training (fourteen 20sec swimming sessions with a weight equivalent to 14-16% of each body weight and 10 sec pause was allowed between exercise sessions, 4days/wk for 6weeks from 12-week-old), and RT: resistance training (ladder climbing, 8-10sets/day, 3days/wk for 8weeks from 10-week-old) groups (n=10 each group). After training session, we measured aortic pulse wave velocity (aortic PWV) as an index of arterial stiffness and plasma nitrite/nitrate (NOx) concentrations and phosphorylation of endothelial nitric oxide (eNOS) and protein kinase B (Akt) proteins in the aorta.
Results: Aortic PWV was significantly reduced in both AT and HIIT groups as compared to CON and RT groups, whereas there was no difference between RT and CON groups. HIIT-induced reduction of aortic PWV was similar to AT. Additionally, phosphorylation of eNOS and Akt proteins and plasma NOx level were significantly elevated in both AT and HIIT groups as compared to CON and RT groups, whereas there was no difference between RT and CON groups. Moreover, HIIT-induced increase in phosphorylation of eNOS and Akt proteins and plasma NOx levels was similar to AT.
Conclusions: These results suggest that short periods of HIIT-induced increase in aortic NO production via the Akt/eNOS signalling pathway may reduce arterial stiffness, as same degree of AT in rats.
Author Disclosures: N. Hasegawa: None. S. Fujie: None. N. Horii: None. I. Tabata: None. M. Iemitsu: None.
- © 2016 by American Heart Association, Inc.