Single Sprint Interval Training Session Induces Faster VO2 Kinetics that is Sustained for 72 Hours

Abstract

The VO2 kinetics response describes the rate of adjustment of the oxidative phosphorylation, providing an overall estimate of the efficiency of the cardiovascular system. Recent lines of evidence have demonstrated that, at least in young individuals, VO2 kinetics can become faster even after only a single session of endurance training, likely due to improvement in the provision of oxygen (O2) to the active tissues. Additionally, sprint interval training (SIT) has been shown to induce positive adaptations in oxidative metabolism. However, the effects of an acute bout of exercise, and more specifically SIT, in the VO2 kinetics response of older individuals are unknown. PURPOSE: to investigate whether a very short session (3 bouts) of Sprint Interval Training (SIT) induces speeding of the VO2 kinetics in older participants. METHODS: Before, as well as 24, 48, and 72 hours post SIT exercise intervention, the time-constant of the VO2 kinetics response (τVO2) was measured in eight older adults (67.3 ± 3.7 years; 21.5 ± 2.4 BMI) through three step transitions in work rate (WR) from 20 W to a moderate-intensity WR that elicited a VO2 corresponding to 90% of the gas exchange threshold. The SIT session consisted of 3 consecutive “all-out” sprints (Wingate protocol) against a resistance corresponding to 5% of the body weight, interspersed by 4.5 min recovery. RESULTS: The average mean power throughout the three Wingate sprints was 366 ± 74 W, while the average peak power was 602 ± 106 W, and the average total work was 22.0 ± 4.4 kJ·min-1. τVO2 at the baseline was 41.8 ± 5.9 s. Significantly (p < 0.05) smaller values in τVO2 kinetics were found 24 h (35.0±4.9 s; -16.2%), 48 h (35.5±3.4 s; -15.1%), and 72 h (37.2±7.2 s; -10.9%) post SIT intervention. CONCLUSIONS: This study demonstrated that a “low-volume” SIT session has the potency to speed the rate of adjustment of the oxidative phosphorylation in older adults. Despite the low dose of exercise, the speeding of the VO2 kinetics occurred within 24 h and was sustained for 72 h, reinforcing the idea that SIT offers beneficial effects to the oxidative system, and that older individuals are capable of favorably adapting to this type of interventions.