Mental And Physical Energy And Fatigue Are Four Distinct But Overlapping Moods

BACKGROUND: Recent evidence published from our lab suggest that individuals may feel mentally and physically energetic and fatigued (ME, PE, MF, PF) simultaneously. Our findings suggest that each mood may have unique biomarkers but overlapping behavioral features. However, many biomarkers remain largely unexplored, and our work has not identified how changes in these moods may impact changes in performance outcomes. PURPOSE: The purpose of this study was to identify the unique biomarkers, physical and cognitive performance measures that change when ME, PE, MF, and PF change. METHODS: Participants (n = 10) completed physical (counter movement jump (CMJ), Isometric Thigh Pull (IMTP), plyometric pushup (PPU), maximum hand release pushups (HRPU), maximum plank, 60s maximum effort cycle, Queens step test) and cognitive tasks (Go-No Go (GNG), Stroop, NBack, Visual Search) pre and post a 60-minute physically fatiguing protocol simulating military training. Saliva was collected, and mood assessed pre-, post, and 1-hour post completion of the tasks. Cortisol, Uric acid, immunoglobulin A (IgA), testosterone, amylase, and IL-6 were extracted from saliva. Mood changes were categorized by direction, with Kappa statistic (K > .61) and Wilcoxon Sign Rank Test (p < .05) used to explain change directionality. RESULTS: Kappa statistic results suggest that directionality of change GNG accuracy (K = .75) and PPU Peak Force Time (K = .67) were associated with changes in ME, while NBack reaction time (K = .70) and CMJ Reaction Strength Index (RSI) (K = .61) were associated with changes in PF. Wilcoxon results suggest when individuals reported an increase in PE (U = 99, p = .02) and ME (U = 99, p = .02) they had lower IgA compared to their prior measure. Individuals who reported an increase in PF after the fatiguing protocol had lower relative changes in recovery heart rate (U = 16, p = .04) compared to baseline. DISCUSSION: The findings are in line with previously published work that cognitive task accuracy was associated with ME while errors were associated with PF. Additionally, this study provided new insight into IgA, PE and ME, as well as anaerobic task performance and ME and PF. The heterogeneity in biological, performance, and cognitive outcomes support examining factors that contribute to heterogenous mood outcomes to a fatiguing protocol.