Metabolic Response of Different High Intensity Aerobic Interval Exercise Protocols
Gosselin, Luc E; Kozlowski, Karl F; DeVinney-Boymel, Lee; Hambridge, Caitlin
Although high intensity sprint interval training employing the Wingate protocol results in significant physiological adaptations, it is conducted at supramaximal intensity and is potentially unsafe for sedentary middle-aged adults. We therefore evaluated the metabolic and cardiovascular response in healthy young individuals performing four high intensity (~90% VO2max) aerobic interval training (HIT) protocols with similar total work output but different work-to-rest-ratio. Eight young physically active subjects participated in five different bouts of exercise over a 3-wk period. Protocol one consisted of 20 min continuous exercise ~70% of VO2max, whereas protocols 2, 3, 4, and 5 were interval based with a work/active rest duration (in seconds) of 30/30, 60/30, 90/30, and 60/60 respectively. Each interval protocol resulted in ~10 minutes of exercise at a workload corresponding to ~ 90% VO2max, but differed in the total rest duration. The 90/30 HIT protocol resulted in the highest VO2, HR, RPE, and blood lactate whereas the 30/30 protocol resulted in the lowest of these parameters. The total caloric energy expenditure was lowest in the 90/30 and 60/30 protocols (~150 kcal), whereas the other 3 protocols did not differ (~195 kcal) from one another. The immediate post-exercise blood pressure response was similar across all protocols. These finding indicate that HIT performed at ~90% of VO2max is no more physiologically taxing than steady state exercise conducted at 70% VO2max, but the response during HIT is influenced by the work-to-rest ratio. This interval protocol may be used as an alternative approach to steady state exercise training, but with less time commitment.