Wellness News May 2003 A suspected cause of chronic fatigue syndrome People who suffer from chronic fatigue syndrome (CFS) may have a minor heart problem that is not easily detected, suggests a small, preliminary study presented at a recent American Physiological Society conference. The study monitored both healthy people and people with CFS while they were exercising on stationary bikes, measuring each participant's heart pumping ability. The results showed that people who had CFS had a decrease in the heart's pumping ability during exercise, whereas the healthy participants showed an increase. The researchers think this decrease in pumping ability may be a sign that the people with CFS may have hearts that are not working efficiently. They believe the problem must be minor because their hearts seem to work fine at rest. However, they say it may also be possible that the people with CFS are showing very early signs of congestive heart failure. This chronic condition makes the heart unable to pump enough blood to the body, which could cause fatigue during stress if blood is sent to critical organs such as the heart and brain first and fails to reach other organs, such as the muscles, adequately. More research is needed, however.