As 1.5-billion people around the world shift from Daylight Saving Time to normal standard time, according to research published in the New England Journal of Medicine by two Swedish doctors - Imre Janszky (Karolinska Institute) and Rickard Ljung (National Board of Health and Welfare) on the relation between sleep and heart attacks, an extra hour of sleep time will reduce the likelihood of heart attack.

Shifting clocks back by an hour will allow an extra hour of sleep time, which the Swedish researchers say lowers the risk of heart attacks, compared to higher risk of heart attack risks during the first week implementing Daylight Savings Time in the spring.

According to the research, insufficient sleep not only raises blood pressure and heart rates, chronic stress also leads to abnormal heart functioning, while lack of sleep in women also makes them more heart attack prone.