Over exercising can also lead to heart attack

Is there a way to assess risk for sudden death from endurance activities? Most of the research has been done around marathons, and the conclusions are controversial. In small studies, non-invasive cardiac imaging, such as electron-beam CT and cardiac MRIs, have been able to determine the level of plaque build up in vessels and cardiac damage respectively.

As in all decisions on the utilisation of technology, when science shows that the stuff works, clinical judgment needs to answer when it should be used. No diagnostic tests to date are able to simulate the extreme impact that a marathon has on the heart. According to Dr. Chauhan, "other than screening not being good enough to predict sudden death, it is not very practical to do so for several thousand people two to three days before a marathon". Until we have better investigative tools, the best we can do is try to reduce the chances by taking preventative measures.

So, what can we do to lower our risks? That one is obvious: We should stay active!

While some of us advise running barefoot, that does not mean you should jump out of bed tomorrow and start on your first 21 km run. You should start endurance sports early in life and not let plaque build up in your heart in the first place.

If it is a bit late for that, before you decide to become an endurance athlete, you should visit a sports medicine specialist and work your regimen up gradually. Run hard, but run often.

Ranjan Das worked and played hard. Could that have been a killer combination? As in most other cases of sudden death, it is unlikely we will find out for sure. We do know, however, that stress - physical or psychological - plays a central role in sudden death. The body often responds in surprising ways to stress. If you begin to do squats, blood will rush to your thighs to give your tiring muscles more oxygen. That is the response to physical stress. Now if you were to sit down at your desk and hyperventilate in panic over a business situation, blood would also be diverted to your limbs.

The physiologist Jay Kaplan did some cool experiments to show the effects of stress on the heart. Kaplan reared monkeys in a situation that gave them high levels of social stress. Even if the monkeys ate well and were active, some of them formed significant amounts of plaques in their coronaries. The fact that not every monkey developed heart disease underlies the important role that genes play in susceptibility to bad coronaries.

A healthy, unstressed person can respond to acute physical or psychological stress by speeding up the heart to get more food and oxygen where needed. If someone is under chronic stress, this response is blunted. Instead of dilating, the arteries will constrict. The body is unable to compensate for the added demand and bad things can happen. When the chronically stressed lawyer jumps up to object to a flagrant violation in court, that emotional stress may give him a fatal heart attack. The same outcome could happen if the lawyer jumps on the treadmill and pushes his body beyond its limit.

In his book, Why Zebras Don't Get Ulcers, Robert Sapolsky suggests ways in which we can reduce our stress levels; his favourite is frequent exercise.

An important qualifier to exercise is that when it's used to combat stress, its mood enhancing and physiological stress-busting impact will last for only a couple of hours. Meditation is another way to reduce stress hormone levels. A caveat to this is that the benefits definitely show during the meditation session, but may not continue for long. Social support is another way to moderate stress. This is not equivalent to being social. Studies of animals have shown that when put in social groups, stress levels actually increase as the animals struggle to compose their social hierarchy. The operative word is "support."

Overall, it is important not to overdo exercise, stress or even the above stress-busting activities. Often doing too much is worse then doing nothing at all. Sometimes even one more mile is just too far.

With inputs from Shweta Bagai, Rohin Dharmakumar and Neelima Mahajan-Bansal

Dr. Kumar is a graduate of Harvard Medical School and Founder and Vice President of Doctor Kares Hospital.