The people most likely to have a heart attack are those who are obese, do not exercise, suffer from diabetes and are over the age of about fifty - it's a combination of factors, not just one. Those with active interests and social contact tend to do better in health in any case.
After the age of fifty, there is wear and tear, the veins and arteries may be clogged with plaque and blood pressure is often raised. This is normal in old age. However, the above precautions do make a considerable difference.