Mood, Cognitive Function, and Plasma Kynurenine Metabolites Responses Following Severe Changes in Physical Activity

Abstract

Purpose To monitor changes in mood, cognitive function, brain electrical activity, and circulating kynurenine pathway metabolites in response to a three-week severe physical activity restriction, followed by three weeks of resumed activity adding resistance and high-intensity interval exercise training. Methods Twenty healthy participants (14 males, six females; 25.4 ± 5.2 years) underwent three weeks of limited physical activity using forearm crutches with one leg suspended (INACT) and then three weeks of resumed activity plus supervised resistance and high-intensity interval training sessions (ACT, three to six sessions per week). At baseline, after INACT, and then after ACT, venous blood was sampled for analysis of major kynurenine pathway metabolites, a short version of the International Physical Activity Questionnaire (IPAQ-SF), Hospital Anxiety and Depression Scale (HADS) and Profile of Mood States (POMS) questionnaires were completed, and cognitive tests with EEG were performed. Results During INACT, the depression score on the HADS scale tended to increase (3.5 to 6.8; p = 0.065), while it was reduced with ACT compared with after INACT (2.8; p = 0.022). On the POMS scale, depression, fatigue, and confusion increased within INACT (p < 0.05). Notably, subjects exhibited considerable variability, and those experiencing depression symptoms recorded by the HADS scale (n = 4) displayed distinct mood disturbances on POMS. All HADS and POMS scores were fully restored to baseline with ACT. Neither INACT nor ACT induced significant changes in cognition, brain electrical activity, or kynurenine pathway metabolites (p > 0.05). Conclusions While young healthy individuals with three weeks of severely restricted physical activity do not undergo changes in circulating kynurenine pathway metabolites, cognitive performance, and brain electrical activity, their mood response is quite variable, and depression develops in some. Three weeks of resuming mobility plus exercise training reversed the mood profile.