{ "abstract": "Background: The interplay between time-restricted eating (TRE), endurance exercise, mood, and tryptophan (TRP) metabolism has not been thoroughly examined. This study evaluated whether changes in psychological well-being co-occurred with changes in serum kynurenine metabolites during a combined TRE and exercise intervention and performed exploratory analyses of kynurenine metabolism. Methods: Seventy-one healthy adults participated in a 12-week endurance training program combined with a 10 h TRE window. Assessments included the State-Trait Anxiety Inventory, Mood Adjective Checklist, body composition, inflammatory markers, and serum kynurenine profiling, conducted at baseline and post-intervention. The pre-specified analysis was performed in the entire cohort, whereas subsequent analyses stratified by age and changes in anxiety were conducted post hoc and should be considered exploratory. Results: The pre-specified analysis of the entire cohort did not reveal statistically significant or clinically meaningful changes in psychological well-being, kynurenine metabolites, or inflammatory biomarkers. In exploratory post hoc analyses, participants were stratified into older (OE-TRE) and younger (YE-TRE) groups. Both groups showed significantly lower body mass and BMI at the second measurement. In the OE-TRE group, serum anthranilic acid (AA) levels increased (Δ = +7.85 nmol/L), while in the YE-TRE group, a decrease was observed (Δ = -2.62 nmol/L). In a separate exploratory post hoc analysis, participants with complete psychological assessment data were stratified according to the direction of change in anxiety scores. Among these participants, 66.7% showed lower anxiety scores in the second measurement, and this anxiety-defined subgroup also showed lower serum 3-hydroxykynurenine (3-HK) concentrations. This observation was confined to the exploratory subgroup analysis and should not be interpreted as a general reduction in 3-HK in the study cohort. The OE-TRE group also showed an increase in the xanthurenic acid (XANA) + picolinic acid (PA) to 3-HK ratio and a reduction in TNF-α. Notably, differences between groups in the 3-hydroxyanthranilic acid (3-HAA)/3-HK and XANA + PA/3-HK ratios observed at baseline were no longer present at the second measurement. In the exploratory subgroup of participants whose 3-HAA concentrations increased over time, soluble gp130 (sgp130) concentrations were lower at the second measurement. Conclusions: The pre-specified whole-cohort analysis did not demonstrate statistically significant or clinically meaningful changes in the primary psychological and biochemical outcomes. Exploratory post hoc analyses suggest that changes in psychological well-being and peripheral kynurenine metabolism may co-occur during a combined TRE and endurance exercise intervention. The observed decrease in 3-HK was restricted to an anxiety-defined exploratory subgroup and was not observed in the study cohort as a whole. These findings are associative and hypothesis-generating and do not establish an intervention effect or causality. The trial was registered as a clinical trial (NCT05229835, date of first registration: 8 February 2022).", "abstract_shown": true, "affiliations": [ "Department of Bioenergetics and Physiology of Exercise, Medical University of Gdansk, Dębinki 1, 80-211 Gdansk, Poland.", "Division of Sport Psychology, Faculty of Social Sciences, Institute of Psychology, University of Gdansk, Bazynskiego 4, 80-309 Gdansk, Poland.", "Department of Health and Natural Sciences, Gdansk University of Physical Education and Sport, Kazimierza Gorskiego 1, 80-336 Gdansk, Poland.", "Department of Athletics, Strength and Conditioning, Poznan University of Physical Education, Krolowej Jadwigi 27/3, 61-871 Poznan, Poland.", "Department of Sport, Gdansk University of Physical Education and Sport, Kazimierza Gorskiego 1, 80-336 Gdansk, Poland.", "Department of Pharmaceutical Pathophysiology, Faculty of Pharmacy, Medical University of Gdansk, 80-210 Gdansk, Poland.", "Department of Environmental Engineering Technology, Faculty of Civil and Environmental Engineering, Gdansk University of Technology, Narutowicza Str. 11/12, 80-233 Gdansk, Poland.", "Department of Sport, Faculty of Physical Education, Kazimierz Wielki University, 85-064 Bydgoszcz, Poland.", "Faculty of Health, WSB Merito University, 80-266 Gdansk, Poland." ], "article_type": "research article", "arxiv": null, "author_total": 13, "authors": [ { "affs": [ 0 ], "name": "Ulana Juhas", "orcid": "0000-0001-8393-5845" }, { "affs": [ 1 ], "name": "Dagmara Budnik-Przybylska", "orcid": "0000-0002-5943-4773" }, { "affs": [ 0 ], "name": "Andżelika Borkowska", "orcid": "0000-0001-9131-3608" }, { "affs": [ 2 ], "name": "Jakub Antoni Kortas", "orcid": "0000-0003-2364-0214" }, { "affs": [ 0 ], "name": "Joanna Reczkowicz", "orcid": "0000-0002-9944-1687" }, { "affs": [ 3 ], "name": "Ewa Ziemann" }, { "affs": [ 4 ], "name": "Katarzyna Prusik" }, { "affs": [ 5 ], "name": "Damian Flis", "orcid": "0000-0002-6176-4536" }, { "affs": [ 0, 6 ], "name": "Grażyna Gałęzowska", "orcid": "0000-0001-9255-3283" }, { "affs": [ 0 ], "name": "Konrad Kowalski" }, { "affs": [ 7 ], "name": "Malgorzata Zychowska" }, { "affs": [ 8 ], "name": "Barbara Kaczorowska-Hać" }, { "affs": [ 0 ], "name": "Jędrzej Antosiewicz", "orcid": "0000-0002-7871-6469" } ], "bibtex": "https://research.draconitic.com/paper/fga37bv4a05yd.bib", "cited_by": 0, "doi": "10.3390/nu18193116", "fulltext_url": "https://europepmc.org/articles/PMC13666859", "id": "fga37bv4a05yd", "issns": [ "2072-6643" ], "landing_url": "https://europepmc.org/article/MED/42884568", "language": "eng", "licence": "CC-BY", "licence_label": "CC BY", "licence_source": "article", "licence_url": "https://creativecommons.org/licenses/by/4.0/", "metadata_licence": null, "native_subjects": [ [ "openalex", "2803|Tryptophan and brain disorders" ] ], "openalex": "W7214020064", "pdf_url": "https://europepmc.org/articles/PMC13666859?pdf=render", "pmcid": "PMC13666859", "pmid": "42884568", "published": "2026-09-22", "publisher": null, "ris": "https://research.draconitic.com/paper/fga37bv4a05yd.ris", "sources": [ { "first_seen": "2026-10-30T12:19:16Z", "native_id": "MED:42884568", "source": "europepmc", "url": "https://europepmc.org/article/MED/42884568" } ], "subjects": [ { "field": "medicine", "origin": "openalex:2803|Tryptophan and brain disorders", "subfield": "psychiatry" } ], "title": "Changes in Mood and Tryptophan Metabolism Following a 12-Week Endurance Exercise Combined with Time-Restricted Eating in Healthy Adults.", "title_text": "Changes in Mood and Tryptophan Metabolism Following a 12-Week Endurance Exercise Combined with Time-Restricted Eating in Healthy Adults.", "type": "peer-reviewed", "updated_at": "2026-10-30T12:19:16Z", "url": "https://research.draconitic.com/paper/fga37bv4a05yd", "venue": "Nutrients", "versions": [] }