Running is often touted as the ideal form of exercise - you don't need any special equipment or have to pay gym fees. But is running long distances really safe for everyone?
Some health experts are now calling for caution, especially for those discovering the joys of running in their later years. The unanimous advice is that runners see their doctors before undertaking strenuous workouts.
"Don't think that when you are 50 that you can do what you did when you were 20," National Heart Foundation NSW executive officer Tony Thirlwell said.
"When you are older you need to be careful. The risk factors for heart disease are genetics, age and sex."
Melbourne cardiologist Dr Andre La Gerche agreed, saying that when it comes to health and marathons, less is sometimes more.
"Why do some amateurs aim to run 10 marathons in a year when professionals recognise that they can only manage two marathons without risking burn-out," he said.
"My personal view is that we should exercise caution when 'celebrating' feats such as running a marathon each day for a year. What we should be doing is celebrating those who incorporate 30-60 minutes of varied exercise into their daily lives."
La Gerche works at St Vincent's Hospital Melbourne and is a visiting scholar in Belgium studying exercise-induced cardiac damage. His Australian study of 40 well-trained endurance athletes found that extreme exercise caused some heart injury or fatigue, which especially affected the right side heart chambers, which are the parts that pump blood into the lungs.
"This injury seemed to be greater in the fitter athletes and was greater the longer the event was, such as in ultra-endurance triathlon," said La Gerche, a keen athlete who has done eight marathons in the past 15 years, including a best time of 2 hours and 29 minutes.
"I am passionate about endurance sport but I really do believe that the body has its limits."
"Our findings are analogous to those changes that we see in the muscles of the arms and legs of these athletes. All intense exercise causes a degree of muscle damage and we believe that the heart is no exception.
"The heart is clearly more important because muscle damage can cause heart rhythm problems.
"We now know that some arrhythmias are more common in endurance athletes (such as atrial fibrillation). However, it is extremely important to point out that these arrhythmias are rare and the benefits of exercise in preventing heart attacks due to heart artery blockages, which are far more common, clearly outweigh the risks," said La Gerche.
In spite of such risks, long distance running continues to grow in popularity.
Dr Trevor Tingate, who runs a medical practice in Sydney's Kirribilli for people who want to exercise hard, is convinced that regular, lifelong exercise is the key to long life and avoiding bowel and prostate cancer as well as heart disease and diabetes.
"The important thing is to include some minutes each session in which your heart rate is at the 85 to 90 per cent mark," Tingate said.
"A lot of people think a quick walk is enough but exercise needs to be vigorous to prevent disease."
The downside was that people who have spent their lives on the couch were at higher risk of heart attack when they first start exercising, he said. He urged people to discuss with their doctor about having a CT scan of their heart to check if there are any blockages in the arteries or other problems.
Running coach Sean Williams, who estimates he runs 100 kilometres a week and has completed 50 marathons and ultra-marathons, said preparation was the key to safe running.
"The moderately fit need to spend at least 16 weeks preparing for a marathon, running at least twice a week (once for about an hour with some speed work and once for up to three hours)," Williams said.
"If you are obese or unfit, you should add in a couple of other runs and some cross-training such as swimming, cycling or deep water running to build up your fitness.
"The biggest mistake people make is bad pace judgment, going too hard at any single point in a marathon. The best thing is to keep your heart rate steady. If your breathing is getting out of control, you will hit the wall much faster. As a guide, try breathing in once every three steps and out once every three steps.
"Heart attacks in marathons are rare and almost always due to pre-existing heart conditions."
A study of 10.9 million marathon or half-marathon runners published in the New England Journal of Medicine found 59 cases of cardiac arrest, where a runner became unconscious with no pulse during the race or within an hour of finishing. Of these, 42 runners died and of the 59 cases, 51 happened in men.
The overall figures translate to one cardiac arrest per 184,000 participants and one death per 259,000 participants, the researchers say.
Dr Aaron Baggish, senior author of the study, points to a shift in attitudes about who can run long distances, saying even a decade ago, 26.2-mile (42-kilometre) marathons were considered appropriate only for very athletic people but that recently people have come to think of it as "something anyone can do".
Still, the National Heart Foundation maintains running is a great way to get fit and protect you from heart disease.
"The important thing before undertaking any fitness routine is to see your GP for a medical check," Thirlwell said.
"If there is a family history of heart disease, especially in your parents, your doctor might order other tests such as a stress test to see what's going on.
"You may well have had a heart attack walking down the street. When you run a marathon it puts your body under some extra stress that may well have brought that genetic defect into play. We don't really know why this can happen."
Thirlwell acknowledges that many men "are not good at going to their GP" and urges them to seek medical advice.
HOW TO RUN SAFELY
1. Get a medical check and tell your doctor about your family history before you start training.
2. Ask for a blood test for cholesterol and blood sugar levels. If there's a history of heart disease ask for a stress test and/or a CT scan of your heart.
3. Build up your training over at least 16 weeks.
4. Maintain your breathing at one breath in or out per three steps.
5. Don't run if you have gastro, a cold or the flu.
6. Keep hydrated.
- Sydney Morning Herald
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