Exercise makes heart `grow'

A gene has been discovered that appears to make the heart grow at a startling rate in response to strenuous physical exercise. The hearts of Army recruits with the gene variant showed 25 times more growth than those without it at the end of a tough 10 week training course, researchers said yesterday.

The scientists were so astonished by their findings that it took them a whole year to ensure they had not made a mistake. They still do not know if they have found a "Rambo" gene that creates super-fit soldiers - or something signifying just the opposite.

It may be that bigger hearts are produced in weaker individuals to help their bodies cope with the physical demands placed on them.

In people with high blood pressure, such heart growth can cause a condition called left ventricular hypertrophy which may double the chances of a heart attack or stroke. Researchers think identifying the gene - a special version of an already known gene called "ACE" - might lead to new methods of treatment.