High-intensity interval training (HIIT) is described as a succession of short-duration, maximum or near-maximum intensity efforts, alternated by periods of recovery during which exercise continues at a lower intensity (active recovery) or is interrupted ( passive recovery).
The results of a study have recently been published (García de Frutos et al, 2021; Int J Environ Res Public Health 16-Apr; doi: 10.3390 / ijerph18084225) whose objective was to evaluate the acute responses of three HIIT protocols of different interval times. work / recovery during the total time of the session, with auto-selectable load and until exhaustion, “all out”.
22 men between 19 and 24 years participated. The HIIT protocol consisted of one of the following three HIIT protocols, of 30, 60 and 90 s of 1: 1 density ratio and with passive rest, with a total duration of exercise of 10 min. The test was performed on a cycle ergometer set to workload mode independent of pedaling frequency.
The results showed that the duration of the work / rest intervals, starting from 30 s of work, was not associated with significant differences in the levels of lactate concentration in the blood, nor in the heart rate. The authors observed that the percentage of maximum power developed achieved in each HIIT protocol is related to the duration of the work intervals.
The authors concluded that HIIT with shorter work-rest time intervals allows maintaining higher power for longer, throughout the work session, without changes in lactate level or loss of power.
When we apply HIIT we must know in advance the objectives we are pursuing and to whom we are going to apply it. If the person who is going to perform HIIT is poorly trained or simply wants to maintain good health, short HIIT is a good option since it involves less physiological stress with significant results on aerobic power. However, when the goal is to improve aerobic power in competitive athletes seeking performance, long HIIT (3-4 min per interval) is the most appropriate choice.