Table 2. Mean rating of perceived exertion and affect during the 60/60 s and the 30/30 s LV-HIIT protocols. 60/60 s 30/30 s p ES RPE (6 to 20) Interval 15.9 ± 1.5 13.9 ± 1.5 0.003 1.33 Recovery 13.2 ± 1.8 12.3 ± 1.4 0.054 0.68 Protocol 14.5 ± 1.4 13.1 ± 1.4 0.002 1.28 Affect (-5 to +5) Interval -0.8 ± 1.4 1.1 ± 2.0 0.007 0.70 Recovery 0.6 ± 1.7 1.7 ± 1.8 0.029 0.82 Protocol -0.1 ± 1.4 1.4 ± 1.9 0.008 1.08 Values are presented as mean ± SD; LV-HIIT, low-volume high-intensity interval training; RPE, rating of perceived exertion; RER, respiratory exchange ratio; ES, effect size (Cohen’s dz); ES < 0.2 reflects a trivial effect, ≥ 0.2 and < 0.6 reflects a small effect, ≥ 0.6 and < 1.2 reflects a moderate effect, ≥ 1.2 and < 2.0 reflects a large effect, ≥ 2.0 and < 4.0 reflects a very large effect, and ≥ 4.0 reflects a nearly perfect effect.