Acute Kidney Injury Associated With Dehydration Protocol Used by Combat Sports Athletes

The medical question

How do preparation and weight-management practices affect a fighter’s health?

The Fight Medicine Research Institute uses this evidence to frame questions about how dehydration before a weigh-in affects kidney markers and how far they recover by fight day. The study’s population and assessment methods determine which questions it can inform.

Summary

In 30 male MMA and Muay Thai fighters, mean blood markers of kidney function shifted on the official weigh-in day, after a mean loss of 10% and 7.7% of body weight, and had moved back towards their starting values by fight day.

What the work reports

• Fifteen MMA and 15 Muay Thai fighters, all men, were assessed three times: about 45 days before a fight, on the official weigh-in day and on fight day, with body weight, blood pressure, heart rate, and blood and urine tests.
• By the weigh-in, fighters had lost a mean of 10% of body weight in the MMA group and 7.7% in the Muay Thai group, and mean estimated glomerular filtration rate was at its lowest (79.1 and 87.2 mL/min/1.73 m2, from 97.7 and 97.2). On fight day it was 96.5 and 102.2.
• The authors conclude that the findings suggest kidney damage associated with dehydration and point to a need to guide fighters towards weight-loss methods that are less harmful.

Limits to keep in mind

• The study had 30 participants, all men, and reports no comparison group.
• The authors state that they had no control over the use of laxatives or diuretics and did not evaluate how the fighters rehydrated between the weigh-in and the fight.
• Measurements ended on fight day, and the authors say prolonged monitoring is needed to tell reversible changes from a progression to chronic kidney disease.
• No criteria for defining acute kidney injury are stated in the article, and some figures in its text differ from those in its tables.

Source issues recorded

• The publisher’s Crossref deposit places this article in issue 1 of volume 2026, with a print date of January 2026. The article itself and Europe PMC give the volume and the article number, with no issue number. The citation here follows the article.
• Some figures in the text differ from the tables. The text gives the Muay Thai group’s weight regain between the weigh-in and the fight as 7.5 kg, where Table 1 gives 4.9 kg. The text says leukocytes were not found in urine on fight day, where Table 2 gives 6.7% for the MMA group. This record takes its figures from the tables.
• In the abstract, the findings are described as an increase in filtration rate. The results and Table 2 show that the estimated glomerular filtration rate fell at the weigh-in. The conclusion refers to elevated creatinine clearance, and the article reports no creatinine clearance values.

Publication status and notices

Published in Translational Sports Medicine, a peer-reviewed journal. Original research article in Translational Sports Medicine.

Form of this work: Version of record. The version of record is the final article as issued by its publisher.

No correction or retraction notice was found in Crossref or Europe PMC when this record was checked.

Fight Medicine Research Institute contribution

Fight Medicine Research Institute selected and catalogued this study, prepared an original research summary and a narrative review, verified its bibliographic details, and maintains the associated citation record. It holds an unmodified copy of the published article under the article’s licence.

PDF files

Article details

Relationship

External research catalogued by the Fight Medicine Research Institute. The original authors, journal and DOI are unchanged.

Published online

2 February 2026

Issue date

January 2026, volume 2026

Repository date

2 February 2026 (Europe PMC first-publication date)

Date used here

2 February 2026 (Crossref publisher deposit, online publication date)

Rights

CC BY 4.0. Open access under the Creative Commons Attribution License (CC BY), as stated by the publisher. The summary on this page is Fight Medicine Research Institute’s own wording. An unmodified copy of the published article is held on this website under this licence. Licence terms.

Source check

12 November 2026, against PubMed Central full text, Crossref and Europe PMC. Checked under the direction of Casey C. Sears, Founder. An LLM was utilized as a research tool with direct human oversight.

Appraisal

The check covered bibliographic details, links, licence and notices. It is not a formal critical appraisal of the full paper.

Clinical review

None. This record is a research summary, not clinical education.

Funding and conflicts

The article states that the study was supported by the São Paulo Research Foundation (FAPESP, processes 2018/16653-7 and 2017/17027-0) and by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES). The authors declare no conflicts of interest.

Catalog

FH-038, added 12 November 2026

Cite the original work

These files cite the work by its own authors, journal and DOI. Fight Medicine Research Institute appears only in a note, as curator of this catalog page.

Antônio André Jarsen Pereira, Lucas Magri, Marina de Moura Bello, Andréia Cristina Febba Gomes, Carlos Eduardo Neves Amorim, Lilian Caroline Gonçalves de Oliveira, et al.. Acute Kidney Injury Associated With Dehydration Protocol Used by Combat Sports Athletes. Translational Sports Medicine. 2026;2026:2946676. https://doi.org/10.1155/tsm2/2946676

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Related on this website

• Fighter Health: Weight cutting, hydration, kidney health and nutrition