Serum metabolomics signatures after an acute bout of combined traditional or high-intensity tactical training in young adults.

Alternative exercise prescriptions and doses would be expected to result in distinct signatures due to differences in duration and intensity. We tested two novel combined endurance and resistance exercise regimens to understand how differing prescriptions alter the timecourse of metabolomics response. Serum metabolomics for n = 37 untrained individuals was completed following traditional combined exercise [TRAD; n = 20 (11M/9F)] or high-intensity tactical training [HITT; n = 17 (8M/9F)] before (pre), and immediately (h0), 3 and 24 h post-exercise (h3 and h24, respectively). We found minimal metabolites had a group by time interaction (4 with FDR-adjusted q values <0.10; 9 with nominal p < 0.01), but both stimuli resulted in large-scale within-group changes to the circulating metabolome. TRAD had greater numbers of differentially abundant metabolites (FDR <0.10) compared to HITT at h0 (451 vs. 358), h3 (446 vs. 348) and h24 (183 vs. 86). The metabolite classes altered were related to key energy substrates for both groups at h0 and energy replenishment for h3 and h24. In summary, our data describe the acute changes in the circulating metabolome following combined endurance and resistance exercise. Additionally, we show the two distinct doses of combined exercise led to generally similar patterns of responses.