Affective and fatigue responses to incremental exercise: the effect of hypoxic and normoxic training protocols

Hypoxic training protocols have been used to improve athletes' performance by influencing both physiological and emotional responses. The aim of the present study was two-fold. First, to evaluate the post-exercise emotional response on the increasing intensity exercise (O_2max) in normoxia and hypoxia. Second, to assess the emotional responses of two hypoxic training protocols (Sleep High-Train Low, SH-TL; Sleep Low-Train High, SL-TH) during increasing intensity exercise (O_2max) in both normoxia and hypoxia.

Twenty-seven physically active males ranging in age from 18 to 30 years volunteered to participate in the study. The participants were randomly assigned into two different hypoxic training protocols (SH-TL, SL-TH), and a control group. Participants performed a protocol to evaluate O_2max in hypoxia and in normoxia. The emotional responses were evaluated based the Activation Deactivation Adjective Check List and the Multidimensional Fatigue Inventory. Repeated measure analysis of variance was applied to examine the differences on participants' mood state and fatigue (energy, tiredness, tension, calmness, general fatigue, physical fatigue, reduced activity, reduced motivation, emotional fatigue) before and after the of O_2max before (pre-test), in the middle (middle-test), and in the end (post-test) of each training protocol.

A significant change in energy in the SL-TH after O_2max was revealed compared to the other groups, between pre- and post-test. In the SH-TL condition, significant differences were found in energy and tension in normoxia, and in tension in hypoxia conditions. In the SL-TH group, significant differences were indicated in tiredness and calmness in normoxia. In hypoxic condition, significant changes were found in tiredness, tension, calmness and general fatigue.

These findings point towards the effectiveness of SL-TH in managing fatigue and maintaining positive emotions. The effect of hypoxic training was noticed in participants mood state, highlighting the importance of a proper design aiming to improve humans' performance in hypoxic and normoxic conditions.