LAURAN NEERGAARD
AP Medical Writer
BETHESDA, Md. (AP) — Researchers hooked Zach Ault to medical monitors as he slowly climbed onto a gym bike. An invisible disease is sidelining this once avid athlete and he knew the simple exercise would wipe him out -- but Ault was pedaling for science.
Chronic fatigue syndrome is one of medicine's most vexing mysteries. Now doctors at the National Institutes of Health are using volunteers like Ault for a unique study that pushes their limits in search of what's stealing all their energy.
"I've tried to exercise my way out of this multiple times and I've put myself in deeper pits every time," said Ault, 36, of Paducah, Kentucky, as he began a nearly two-week stint at the research-only hospital outside the nation's capital.
"Chronic fatigue is kin
