Study – Rapid Weght Cuts By MMA Fighter Linked to Renal Damage

Adding to this site’s database of combat sports safety studies, a recent study was published in the Journal of Hypertension finding that rapid extreme weight cutting by a mixed martial artist was likley linked to renal damage.

In the study, titled “IN MIXED MARTIAL ARTS (MMA) WEIGHT LOSS BY DEHYDRATION RESULTS IN ACUTE EFFECTS ON KIDNEY FUNCTION“, the authors followed an MMA athlete who would lose approximately 7 kg (about 15.4 pounds) via dehydration to make weight for fights. The fighter displayed evidence of renal damage. The authors have data of other fighters and are still analyzing their findings but found it prudent to note that MMA fighters should be counselled avoid these profound dehydration practices when looking to make weight.

The full abstract reads as follows:


Currently there is a significant growth in the world in the number of professional fighters and practitioners of Mixed Martial Arts (MMA). To promote greater preservation of athletes physical integrity, weight categories were created, however some fighters in the attempt of insertion into inferior categories, use the dehydration for their drastic weight reduction. The method used may trigger some damage to the body, such as a decrease in the volume of renal blood flow. We aimed to identify the acute effects of weight loss by dehydration on kidney function in a MMA fighter.

Design and method: 

The volunteer is MLC, 34 years old, male, black, single, resident in Maceió-AL-Brazil, without metabolic diseases, with a family history of arterial hypertension. It does not use drugs or dietary supplementation. The athlete has participated in the fights in the last 3 years, losing 7 kg per dehydration for a month before the fight. The signature of the Free and Informed Consent Term was collected. Three collections were carried out: one month before the fight, in the official weighing day and the day of the event.


In this study in response to reduction of body weight by dehydration of around 7 kg, it was observed that the athlete presented some abnormalities during the body weight loss/gain cycle as glycosuria, non-reversible positive leukocyturia and proteinuria within 24 hours, elevated serum creatinine (1.3 mg/dL) and urea (42 mg/dL) during the peak of dehydration (day of weighing and fighting). Blood ureic nitrogen/creatinine ratio (15.8) and creatinine clearance (126.1 mL/min) were elevated during the three moments of observation, namely 30 days pre-fight, day of weighing and fighting.


Elevated creatinine clearance suggests renal damage with increased filtration rate with possible renal damage from dehydration. We are completing the analysis of 10 athletes. Our data suggest that athletes need to be instructed so that the training method is less detrimental to their physical integrity.


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