CAN THE HEART GET TIRED?

The heart is not usually considered an organ that needs rest. However, Douglas and colleagues have demonstrated that extreme exercise induces transient systolic and diastolic changes that can best be interpreted as cardiac fatigue.

After obtaining echocardiograms from 21 athletes who participated in the Hawaii Ironman Triathlon, the investigators found that contractility and ventricular filling were both decreased at the end of the race. All these athletes also had marked increases in creatine kinase and its MB (cardiac) fraction. All measurements returned to normal during the recovery period.

These data provide yet another good excuse to watch such events on television rather than participate in them.