ORIGINAL RESEARCH article
Front. Physiol.
Sec. Exercise Physiology
Volume 16 - 2025 | doi: 10.3389/fphys.2025.1608584
Athletic Pseudonephritis in Male Cross-Country Ultra-Marathoners: A Comparative Observational Study
Provisionally accepted
Cheng-Hsun LEE1Kai-Hung Chen2
PANG-YEN CHEN2
Li-Hua Li3
Chorng-kuang How3
Yen Kuang Lin4Wei-Fong KAO5
Yu-Hui CHIU2*
Ding-Kuo Chien2
Wen Han Chang2- 1Saint Paul’s Hospital, Taoyuan, Taiwan
- 2Mackay Memorial Hospital, Taipei, Taiwan
- 3Taipei Veterans General Hospital, Taipei, Taipei County, Taiwan
- 4National Taiwan Sport University, Taoyuan City, Taiwan
- 5Taipei Medical University, Taipei, Taipei County, Taiwan
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Athletes have commonly reported hematuria, cylindruria, and proteinuria, which are consistent with "athletic pseudonephritis." To date, little is known about the overall consequences of 100 km (62.5mile) cross-country ultra-marathons on Asian male runners is limited. This study aimed to examine (i) acute urinary changes in runners with athletic pseudonephritis following a 100 km cross-country ultra-marathon and (ii) whether this phenomenon is associated with the runners average running speed.Twenty male Taiwanese ultra-marathoners were prospectively recruited. Urinary parameters were analyzed before and immediately after the 2020 Taiwania 100K Ultra Trail. Competitors ran on a rugged forest path and the official cut-off time was 15 h.Participants showed a statistically significant post-race increase (p < .001) in urinary red blood cell counts. No significant difference was noted in urinary cast in the immediate post-race values compared to the pre-race values (p = .488). Urinary chemistry showed statistically significant increases in specific gravity (p < .001), osmolality (p < .001), creatinine (p = .027), microalbumin (p < .001), protein (p < .001), and myoglobin (p < .001) between the pre-and post-race values. Additionally, 10 (50%) post-race specimens had albumin-to-creatinine ratios >30 mg/g, and 9 (45%) specimens showed protein-to-creatinine ratios >0.2 mg/mg. The association between running speed and red blood cells in urine showed a p-value of .368. There were no correlations between running speed and changes in albumin-to-creatinine ratio (rs = -.105, p = .661), protein-to-creatinine ratio (rs= -.013, p = .957), or myoglobin (rs = .003, p = .99) levels.Exercise-related hematuria and proteinuria were frequently observed in the Asian male cross-country ultra-marathoners. A faster running speed was not associated with the degree of exercise-induced hematuria, proteinuria or myoglobinuria.
Keywords: cross-country ultra-marathon, Hematuria, Myoglobinuria, athletic pseudonephritis, Proteinuria, urine cast
Received: 09 Apr 2025; Accepted: 31 Jul 2025.
Copyright: © 2025 LEE, Chen, CHEN, Li, How, Lin, KAO, CHIU, Chien and Chang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Yu-Hui CHIU, Mackay Memorial Hospital, Taipei, Taiwan
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