Exercise & FitnessFitness predicts survival in kidney disease regardless of body weight
Doctors have long noticed that people with chronic kidney disease who carry extra weight often outlive thinner patients, a pattern called the obesity paradox. This study of 13,521 US veterans with kidney disease asked how physical fitness fits in. Everyone had completed a treadmill stress test and was followed for about 7.4 years. Heavier patients did live longer than normal-weight patients, with 29% lower mortality risk in the obese group. But fitness was the stronger signal. The fittest quartile had 51% lower mortality than the least fit, at every body size. Normal-weight patients with poor fitness fared worst, with 55% dying during follow-up. The study is observational and almost entirely male, so it cannot prove that training saves lives, but it suggests fitness testing deserves a place in kidney care.
