Ultra runners' kidneys under the microscope in new study

This study looks at how running 100 miles in hot conditions affects the kidneys. Researchers will collect urine and finger-prick blood samples from 30 runners before and after the race, and track their effort with a GPS watch and heart-rate strap. The goal is to find out how often kidney stress happens and what factors, like dehydration or pain meds, might contribute. No follow-up is needed, and results will help make ultramarathon training and medical care safer.