The Same Gain for Less Pain When Using Rating of Perceived Exertion Instead of Maximal Aerobic Speed to Prescribe High-Intensity Interval Training

The purpose of the study was to investigate if rating of perceived exertion (RPE) is superior to maximal aerobic speed (MAS) for maximizing time spent ≥ 90% of maximal oxygen uptake (t ≥ 90% VO_2max) during high-intensity interval training (HIIT). Thirteen male physical education students volunteered to perform maximal incremental exercise test and two HIIT sessions. The HIIT sessions included three 3-min intervals prescribed at either RPE 5 (HIIT_RPE) or 85% MAS (HIIT_MAS) interspersed with 2-min passive rest. Borg's category-ratio-10 (CR-10) scale was used for RPE-based HIIT prescription. Heart rate (HR), respiratory gas exchange and running speed were continuously monitored during testing and training sessions. Blood lactate concentration was assessed within the first minute after concluding the HIIT bout. Peak HR (183.7 ± 11 vs. 187.9 ± 9 bpm, p = 0.028), peak respiratory frequency (ƒ_R) (56.7 ± 5.5 vs. 59.8 ± 6.4 bpm, p = 0.046), blood lactate concentration (9.6 ± 2.8 vs. 11.7 ± 2.3 mmol/L, p = 0.049) and session RPE (5.1 ± 0.6 vs. 6 ± 0.9 au, p = 0.021) were all significantly lower during HIIT_RPE when compared to HIIT_MAS. Peak and average speed, VO₂, carbon dioxide output, minute ventilation, tidal volume, and respiratory exchange ratio, average HR and average ƒ_R, and t ≥ 90% VO_2max/HR_max were not significantly different between sessions. RPE-based prescription enables accumulation of similar t ≥ 90% VO_2max/HR_max with lower peak cardiorespiratory, metabolic and perceptual strain in comparison to MAS-based HIIT prescription. This prescription strategy can be used to alleviate physiological stress while still acquiring the same t ≥ 90% VO_2max/HR_max.