There is no doubt that there are numerous benefits to exercise.

We see the popularity of half-marathons and long-distance running, promoted locally in a bid to foster a healthy lifestyle.

But what about the benefits or dangers of exercising excessively?

Recent findings suggest that exercising too much can cause the body to enter a catabolic state, resulting in tissue breakdown, due to excessive release of stress hormones, which not only contribute to catabolism but also to chronic disease.

Microscopic tears in muscle fibres and risk of injuries, along with the weakening of the immune system, may also occur.

But what is of more concern are recent scientific studies which may explain the sudden death of elite athletes.

They suggest that excessive exercise puts extraordinary stress on the heart. This results in high levels of oxidative stress, inflammation and damage to the heart tissues, producing changes that can trigger a cardiac event.

The risks appear to be higher in middle-aged males and particularly in those with underlying hidden cardiac problems.

A 2010 study by the American College of Cardiology showed that endurance runners have more calcified plaque in their arteries than those who are not endurance athletes.

A 2011 German study revealed a very high incidence of carotid and peripheral atherosclerosis among male marathon runners.

A 2012 study in the European Heart Journal found that long-distance athletes suffer from diminished function of the right ventricle of the heart and increased cardiac enzymes after endurance racing, which may activate platelet formation and clotting.

Twelve per cent of the athletes had detectable scar tissue on their heart tissue one week post-race.

A research cardiologist found that 50 per cent of marathon deaths occur in the final mile of the race, probably due to cumulative stress on the heart.

What is apparent now is that excessive exercise, particularly in not-so-fit individuals, causes damage to the heart.

What is contributory is that endurance athletes often do not allow their bodies to fully recover between races.

The right amount of nourishment and exercise is the safest way to good health.

Too little or too much is not the right way to go.

Quek Koh Choon (Dr)