Two distinct doses of combined endurance and resistance exercise led to generally similar patterns of metabolomics responses, with both stimuli resulting in large-scale within-group changes to the circulating metabolome despite minimal group-by-time interactions.
Key Findings
Results
Both traditional combined exercise (TRAD) and high-intensity tactical training (HITT) produced large-scale within-group changes to the circulating metabolome despite minimal differences between groups.
Study included n=37 untrained individuals: TRAD n=20 (11M/9F) and HITT n=17 (8M/9F)
Only 4 metabolites showed a group-by-time interaction with FDR-adjusted q values <0.10
9 metabolites showed a group-by-time interaction with nominal p<0.01
The two distinct doses of combined exercise led to 'generally similar patterns of responses'
Results
TRAD produced greater numbers of differentially abundant metabolites than HITT at all post-exercise timepoints.
At h0 (immediately post-exercise): TRAD had 451 vs. HITT 358 differentially abundant metabolites (FDR <0.10)
At h3 (3 hours post-exercise): TRAD had 446 vs. HITT 348 differentially abundant metabolites (FDR <0.10)
At h24 (24 hours post-exercise): TRAD had 183 vs. HITT 86 differentially abundant metabolites (FDR <0.10)
The number of differentially abundant metabolites declined substantially by 24 hours in both groups, with HITT showing a more pronounced decline
Results
The metabolite classes altered immediately post-exercise were related to key energy substrates for both groups, while later timepoints reflected energy replenishment.
At h0, metabolite changes were related to 'key energy substrates for both groups'
At h3 and h24, metabolite changes were related to 'energy replenishment'
Serum metabolomics was measured at four timepoints: before (pre), immediately post (h0), 3 hours post (h3), and 24 hours post-exercise (h24)
The study characterized the acute timecourse of metabolomics response following combined endurance and resistance exercise
Background
The study design tested two novel combined endurance and resistance exercise regimens with differing prescriptions expected to result in distinct metabolomic signatures.
TRAD refers to traditional combined exercise and HITT refers to high-intensity tactical training
Participants were untrained individuals
The rationale was that 'alternative exercise prescriptions and doses would be expected to result in distinct signatures due to differences in duration and intensity'
Serum metabolomics was used to understand how differing prescriptions alter the timecourse of metabolomics response
What This Means
This research examined how different types of combined exercise — traditional exercise (TRAD) and high-intensity tactical training (HITT) — affect the collection of small molecules circulating in the blood (the metabolome) in untrained young adults. Blood samples were taken before exercise, immediately after, 3 hours after, and 24 hours after exercise in 37 participants. The researchers used a technique called metabolomics to identify and measure hundreds of different metabolites simultaneously.
The study found that while both exercise types caused dramatic changes in blood metabolites, there were surprisingly few differences between the two types of training in terms of which metabolites changed. Immediately after exercise, both groups showed changes in metabolites related to energy use, and by 3 and 24 hours post-exercise, the changes shifted toward metabolites associated with energy replenishment and recovery. Traditional exercise produced somewhat more metabolite changes than HITT at all timepoints, but the overall patterns were similar. By 24 hours, the number of altered metabolites had decreased substantially in both groups, suggesting partial metabolic recovery.
This research suggests that despite differences in exercise intensity and structure between TRAD and HITT, the body's broad metabolic response to a combined endurance-and-resistance workout follows a similar trajectory in untrained individuals. This has potential implications for understanding exercise recovery and how the body adapts to different training protocols, though the similar metabolic signatures across the two regimens may indicate that exercise type matters less than overall metabolic demand for these short-term responses.
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Graham Z, Pathak K, Garcia-Mansfield K, Lavin K, Torres A, McAdam J, et al.. (2026). Serum metabolomics signatures after an acute bout of combined traditional or high-intensity tactical training in young adults.. Physiological reports. https://doi.org/10.14814/phy2.71094