Fitness health centre

Marathon running and your health

The staging of the Olympic marathon on the streets of London may inspire thousands more people to enter events like the London Marathon and Great North Run, but are there long term health benefits of training for a 26.2 mile run - and what are the risks?

We look at the evidence - and speak to an expert - Professor Sanjay Sharma, medical director of the Virgin London Marathon.

Heart risks

A study of London Marathon runners published in 2007 in Sports Medicine found that cardiac arrests occur even in the most experienced runners. Coronary artery disease was the most common cause of sudden cardiac arrest (SCA) in five deaths and six resuscitations.

However, hypertrophic cardiomyopathy or idiopathic left ventricular hypertrophy (HCM) was diagnosed in post mortems on three occasions.

The cardiac arrests were at the finish in less than one-third of cases and the remainder occurred between six and 26 miles on the course.

Only one of the eight runners who died had reported symptoms to his family or doctor which suggested cardiac disease.

When it comes to your heart health, researchers say don't let age alone make you reluctant to run a marathon.

German research, reported at the annual European Society of Cardiology meeting in 2010, found that amateur runners aged over 50 and as old as 72, experienced some temporary heart changes, but no lasting damage after the 26.2-miles.

"The results are comforting for older runners," said study head Dr Fabian Knebel, a cardiologist at the Medical Clinic for Cardiology, Angiology, and Pneumology at the University Medicine Berlin.

Water

The day can start cool, and warm up during the long hours of running.� Experts say it is important to keep hydrated during a long race, but there are dangers of drinking too much water.

In 2007, a 22 year old fitness instructor called David Rogers died after drinking too much water during the London Marathon as temperatures rose.

Most runners are cautioned to ''hydrate, hydrate, hydrate," but a 2010 study published in the British Journal of Sports Medicine suggested that just drinking enough to cover thirst works better for� performance.

Marathon officials suggest runners should always have a medical check-up before taking part.

Officials say dehydration is the biggest problem that marathon runners have to overcome, but also advise runners not to over hydrate during the race. They say to sip water at every drinks station, but not in excess.

Around 700,000 330ml bottles of water are provided for the London Marathon in addition to runners' own drinks.

Also, if runners don?t usually take glucose drinks or supplements when training, they shouldn?t start using them on race days as their bodies won?t be used to them.