Markers of Organ Stress/Injury Elevated After Running a Marathon

MONDAY, Dec. 29, 2025 (HealthDay News) — Markers of organ stress/injury are increased after running a marathon, with no differences seen based on sex or hydration status, according to a study published online Nov. 18 in the Journal of Applied Physiology.

Zachary J. McKenna, Ph.D., from the University of Arkansas in Fayetteville, and colleagues examined the changes in blood- and urine-based biomarkers of organ stress/injury and hydration before and after the 2024 Boston Marathon, comparing responses between men and women and euhydrated and hypohydrated runners. A total of 72 runners (34 men/38 women) had blood and/or urine samples taken before and after the race. The samples were assayed for markers of hydration, intestinal injury, skeletal muscle damage, and acute kidney injury.

The researchers found that from prerace to postrace, markers of hydration were elevated, but only 25 to 34 percent of runners were considered to be hypohydrated postrace. Postrace, all markers of organ stress/injury were increased (fold change: 1.3 to 1,455); no differences were seen based on sex or hydration status.

“These findings should be considered when designing interventions aimed at minimizing various gastrointestinal and renal-related health complications associated with marathon running to promote both health and performance in recreational, [competitive] marathon runners,” the authors write.

Abstract/Full Text