London, Feb 13 : Regular physical activity can not only improve our overall fitness but it can also lower the chance of dying immediately from a heart attack, a new study suggests. The study, published in the European Journal of Preventive Cardiology, showed that a higher level of physical activity was associated with a lower risk of instant and 28-day fatal heart attack, seemingly in a dose-response-like manner. Patients who had engaged in moderate and high levels of leisure-time physical activity had a 33 per cent and 45 per cent lower risk of instant death compared to sedentary individuals. At 28 days these numbers were 36 per cent and 28 per cent, respectively. "Almost 18 per cent of patients with a heart attack died within 28 days, substantiating the severity of this condition. We found an immediate survival benefit of prior physical activity in the setting of a heart attack, a benefit which seemed preserved at 28 days," said researcher Kim Wadt Hansen of Bispebjerg Hospital in Denmark. For the study, the team used data from 10 European observational cohorts including healthy participants with a baseline assessment of physical activity who had a heart attack during follow-up - a total of 28,140 individuals. Participants were categorised according to their weekly level of leisure-time physical activity as sedentary, low, moderate or high. The association between activity level and the risk of death due to a heart attack (instantly and within 28 days) was analysed in each cohort separately and then the results were pooled. A total of 4,976 (17.7 per cent) participants died within 28 days of their heart attack - of these, 3,101 (62.3 per cent) died instantly. The guidelines recommend that healthy adults of all ages perform at least 150 minutes a week of moderate-intensity or 75 minutes a week of vigorous-intensity aerobic physical activity or an equivalent combination thereof, the study suggested. /IANS