Abstract
Effects of 100-km Ultramarathon on Acute Kidney Injury
Ultramarathons are becoming more popular worldwide, allowing for increased insight into the physiological adaptive response to extreme endurance running. In this prospective observational study, investigators examined the acute consequences of a 100-km ultramarathon running event in Taipei, Taiwan. Study exclusion criteria included history of renal dysfunction, heart disease, seizure, musculoskeletal injury, syncope, chest pain, and dyspnea of unknown origin. All participants were required to complete the 100-km ultramarathon within 14 hours in a temperature-controlled, indoor environment. In addition to baseline demographic and training information, blood samples were collected 1 to 2 weeks before the race, immediately after the race, and 1 day after the race. Urine was also collected, and clinical symptoms of exhaustion, hematuria, muscle cramping, and vomiting were recorded every 4 hours during the race. Renal function was evaluated, and acute kidney injury (AKI) was defined based on the Acute Kidney Injury Network criteria.
In all, 26 Taiwanese runners were included in the study, with 25 males and 1 female, and ages ranged from 43 to 53 years. Immediately after the race, 85% of the subjects were diagnosed with AKI. During or immediately after the race, 65% of the runners had moderate dehydration, 23% had muscle cramps, and 12% had hematuria. Although serum potassium, creatinine, renin, and aldosterone were significantly elevated immediately after the race, these numbers decreased to baseline levels within 1 day. Serum creatine kinase, creatine kinase–myocardial band, urine potassium, and urine creatinine levels were significantly elevated immediately after the race and then were significantly reduced 1 day after the race.
The investigators found that transient AKI and exertional rhabdomyolysis are common in ultramarathon runners, with renal function returning to normal within 1 day. Limitations of the study include small sample size, lenient selection criteria, variable timing of baseline blood draws, and using weight loss to approximate hydration status. The investigators suggest that improving athlete awareness of signs and symptoms of AKI may allow them to seek intervention while in the race, thereby improving both race performance and decreasing post-race complications.
(Clin J Sport Med. 2015;25:49–54). W Kao, S Hou, Y Chiu, et al.
Prepared by Lauren Valbracht, MSIII, Temple University School of Medicine, Philadelphia, PA, USA.