Eight-time Olympic champion Birgit Fischer has given up her attempt to qualify for the London Games at age 50.
The German canoeist says she is suffering from a heart muscle inflammation and has been told by doctors that she cannot compete.
Fischer tells Die Welt newspaper that "health is more important than any medal."
Doctors stopped Fischer from competing at the German trials this month after diagnosing her with an irregular heartbeat.
Fischer last competed at the Athens Games in 2004.