Study probes heart and lung function in ME/CFS to unravel Post-Exertion crash

This study looked at heart and lung function in 106 people with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) to better understand post-exertional malaise—the severe worsening of symptoms after physical activity. Participants did two maximal exercise tests on consecutive days. Those with low blood volume on the first day received either a saline infusion or a sham infusion before the second test. The goal was to see how blood volume and exercise capacity relate to post-exertional malaise.