Reducing training frequency from 3 or 4 sessions/week to 2 sessions/week does not attenuate improvements in maximal aerobic capacity with reduced-exertion high-intensity interval training (REHIT).

In the present randomised-controlled trial we investigated the effect of reduced-exertion high-intensity interval training (REHIT) training frequency (2, 3, or 4 sessions/week for 6 weeks) on maximal aerobic capacity in 42 inactive individuals (13 women; mean ± SD age: 25 ± 5 years, maximal aerobic capacity: 35 ± 5 mL·kg·min). Changes in maximal aerobic capacity were not significantly different between the 3 groups (2 sessions/week: +10.2%; 3 sessions/week: +8.1%; 4 sessions per week: +7.3%). In conclusion, a training frequency of 2 sessions/week is sufficient for REHIT to improve maximal aerobic capacity. We demonstrate that reducing REHIT training frequency from 3 or 4 to 2 sessions/week does not attenuate improvements in the key health marker of maximal aerobic capacity.