Chandigarh, May 19 -- Summer heat and humidity make most of us uncomfortable, but this can be deadly for heart patients. The heart responds to a rise in temperature by pumping faster. Simultaneously, blood vessels of the skin dilate, facilitating the flow of warm blood from internal organs to the body surface, observed as a flushed face on a hot day. Moderate exercise may result in up to tenfold increase in heat production with a resultant rise in heart rate . Strenuous physical effort in hot and humid weather may be particularly deleterious in heart disease as it lowers the threshold for a heart attack....