A Single Exercise Session Elicits a Transient Kynurenine Metabolic Signature in Health and Disease: A Systematic Review and Meta-Analysis.
Marcus Vinicius Dos Santos Rangel, Gabriela Andrade Paz, Maria das Graças C Souza et al.
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In 30 seconds
This systematic review and meta-analysis examined acute changes in circulating tryptophan (TRP) and kynurenine-pathway metabolites after a single exercise session. The review included 24 clinical trials (n = 695), with 20 contributing to meta-analysis. Immediately after exercise, TRP decreased, while kynurenine (KYN), the KYN/TRP ratio, kynurenic acid (KYNA), and quinolinic acid (QA) increased. During recovery, TRP remained reduced and the KYN/TRP ratio elevated; KYNA remained elevated, whereas KYN and QA moved toward baseline. Responses varied by population, training status, and exercise modality.
Key findings
- Immediately after exercise, TRP decreased and KYN, KYN/TRP, KYNA, and QA increased.
- During recovery, TRP remained reduced and KYN/TRP elevated; KYNA remained elevated, while KYN and QA moved toward baseline.
- Subgroup analyses suggested larger TRP and KYNA responses in healthy and trained participants and after aerobic exercise.
Why it matters
The findings indicate that one exercise session can produce short-lived changes across the kynurenine pathway, a system involved in energy homeostasis and immune, inflammatory, and neurobiological regulation. The variation by population, training status, and exercise modality is relevant when interpreting metabolite measurements after exercise. The results describe acute metabolic responses, not evidence of sustained pathway change or clinical benefit.
What to keep in mind
The review included 24 trials, and only 20 contributed data to meta-analysis. The abstract reports heterogeneous, context-dependent responses and does not provide pooled effect sizes.