Cognitive Function And Affective States Following Exercise Under Severe Hypoxia.

It has been suggested that acute exercise improves cognitive function. Recent studies indicated that cognitive function improves during exercise under moderate hypoxia. However, it is unclear how cognitive function and affective states are influenced after exercise under severe hypoxia. PURPOSE: The purpose of this study was to determine cognitive function and affective states following exercise under normoxia and severe hypoxia. METHODS: The participants performed cognitive tasks at rest (pre) and after exercise (post) under normoxia and severe hypoxia (FIO2=0.12). The participants cycled an ergometer at 30% peak VO2 for 5 min as a warm-up exercise, and then cycled at 50% peak VO2 for 15 min in the respective conditions. We used a Stroop task where executive function is required. Executive function was assessed by reaction time (RT) and accuracy of the task. Stroop-interference was calculated by subtracting RT in the neutral trial from that in the incongruent trial. The Mood Check List-short form 2 (MCL-S.2) was used to assess affective states. We measured blood flow velocity in the middle cerebral artery (MCAv) using transcranial Doppler ultrasonography during the cognitive tasks at rest and after exercise. RESULTS: We observed no differences in accuracy of the task between at rest and after exercise in both conditions. The Stroop-interference was not altered after exercise in hypoxia condition (pre: -2.1 ± 27.6, post: -3.6 ± 24.4 ms), while the Stroop-interference significantly increased after exercise in the normoxic condition (pre: 9.0 ± 39.6, post: 79.9 ± 29.1 ms, p < 0.001). MCAv tended to increase after exercise relative to rest in the hypoxic condition (pre: 48.2 ± 12.7, post: 50.8 ± 16.8 cm/s, P = 0.07). In contrast, we observed no differences in MCAv between pre and post in the normoxic condition (pre: 47.5 ± 12.8, post: 40.2 ± 12.5 cm/s). The results of MCL-S.2 indicated that anxiety significantly decreased in the hypoxic condition (pre: -8.2 ± 2.3, post: -11.4 ± 1.3, P = 0.02). However, anxiety was not affected in the normoxic condition (pre: -10.6 ± -2.19, post: -10.6 ± 2.6). CONCLUSIONS: These results suggest that the absence of impairments in executive function and improved anxiety in the hypoxic condition may be, at least in part, due to an increase in cerebral blood flow following exercise under severe hypoxia.