Comparison of physiological and psychobiological acute responses between high intensity functional training and high intensity continuous training.

Little is known about the physiological and psychobiological responses that occur during and after high intensity functional training (HIFT). We compared physiological and psychobiological responses during and after a HIFT session with a high intensity continuous training (HICT) session. Twenty-one trained and healthy men were submitted to 20-min session of HIFT and HICT on separate days. The heart rate, blood lactate concentration [Lac], levels of state anxiety, rates of perceived exertion (RPE) and perceived discomfort (RPE-D), and affective valence were measured. Exercise intensity of the HICT was adjusted to the mean heart rate obtained in the HIFT session. The highest heart rate in the training sessions was significantly higher in HIFT (mean ​± ​standard deviation []: [187 ​± ​9] bpm) than in HICT (mean ​± ​: [178 ​± ​8] bpm,  ​< ​0.001). The [Lac] was significantly higher immediately after the HIFT (median [interquartile range ()]: 6.8 [4.4] mmol/L) than the HICT (median []: 3.2 [1.9],  ​= ​0.021) and 10 ​min after (median []: HIFT ​= ​6.8 [4.9] mmol/L, HICT ​= ​2.9 [2.4] mmol/L,  ​= ​0.003). The RPE was also significantly higher in the HIFT (median []: HIFT ​= ​20 [2], HICT ​= ​15 [5],  ​= ​0.009). The physiological and psychobiological responses compared between HIFT and HICT sessions are similar, except for the higher heart rate obtained during the sessions, [Lac] and RPE. Probably, the results found for the higher heart rate obtained during the sessions, [Lac] and RPE may be explained by the higher participation of the anaerobic glycolytic metabolism during the HIFT session.