METABOLIC RESPONSE OF DIFFERENT HIGH-INTENSITY AEROBIC INTERVAL EXERCISE PROTOCOLS

Gosselin, LE, Kozlowski, KF, DeVinney-Boymel, L, and Hambridge, C. Metabolic response of different high-intensity aerobic interval exercise protocols. J Strength Cond Res 26(10):2866-2871, 2012-Although high-intensity sprint interval training (SIT) 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 4 high-intensity (similar to 90% (V) over dotO(2)max) aerobic interval training (HIT) protocols with similar total work output but different work-to-rest ratio. Eight young physically active subjects participated in 5 different bouts of exercise over a 3-week period. Protocol 1 consisted of 20-minute continuous exercise at approximately 70% of (V) over dotO(2)max, whereas protocols 2-5 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 approximately 10 minutes of exercise at a workload corresponding to approximately 90% (V) over dotO(2)max, but differed in the total rest duration. The 90/30 HIT protocol resulted in the highest (V) over dotO(2), HR, rating of perceived exertion, 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 (similar to 150 kcal), whereas the other 3 protocols did not differ (similar to 195 kcal) from one another. The immediate postexercise blood pressure response was similar across all the protocols. These finding indicate that HIT performed at approximately 90% of (V) over dotO(2)max is no more physiologically taxing than is steady-state exercise conducted at 70% (V) over dotO(2)max, 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.