Young athletes are three times more likely to have a sudden heart attack than their peers who are not active in sports, a senior cardiologist warned yesterday. «Physical exercise is good for the heart but can have dramatic results if the necessary precautions are not taken,» the director of Aristotle University’s Sports Medicine Laboratory, Asterios Deliyiannis, told an international cardiology summit in Thessaloniki. Deliyiannis said young athletes should undergo health tests, including electrocardiograms, to ensure they are fit for regular intensive exercise. The laboratory at Aristotle University examines between 30 and 40 young athletes daily and only 1 percent of them reveal serious heart problems, he said. One in three young athletes also suffer from an abnormal heart rhythm but this is rarely cause for concern, he added.