Resetting clocks can reduce heart attack deaths: Study

Sweden, October 30: The results of one of the most fascinating kind of studies show that just by resetting clocks to standard time every year can lead to a 5 percent drop in deaths due to heart attack.

The team of Swedish researchers also found that the susceptibility to heart attacks increases with the onset of daylight saving during the spring season.

While setting their clocks ahead last March, Dr. Imre Janszky of the Karolinska Institute and Dr. Rickard Ljung of Sweden’s National Board of Health and Welfare, decided to see the link between heart attacks and sleep. They wanted to see the effect of moving into and out of daylight saving time.

Both the epidemiologists studied the data containing a list of all heart attacks in Sweden as a consequence of which people were hospitalized or eventually died.

The time period between 1987 and 2006 was taken into account. The researchers counted the number of heart attacks on the seven days after clocks were changed during this time. The number of heart attacks before and after each of those days was also calculated. An average was taken out and finally the gathered data was compared.

It was concluded that on an autumn Monday, the number of heart attacks was 2140. But on the Monday after daylight saving time ended, the same statistics fell to 2038, showing a 5% drop.

The rate also dropped down on five of the other six days of the week but these figures were not big enough to be considered statistically significant. During the spring, the number of heart attacks jumped by up to 6 to 10 percent on Monday, Tuesday and Wednesday after daylight saving time began.

Dr. Ralph Brindis, vice president of the American College of Cardiologydefine who practices in Oakland, said that daylight saving time is one of the miniscule events of our daily life which can affect our heart.

Scientists suspect that sleep deprivation could be the plausible explanation for this phenomenon. This is because lack of sleep is not good for the heart, as it increases blood pressure, heart rate and the tendency to from life-threatening clots.

But Dr. Martha L. Daviglus, professor of preventive medicine at Northwestern University’s Feinberg School of Medicine in Chicago, said that daylight saving time will not be a big factor affecting people’s health until and unless they take into account smoking and overeating. She said, “Ninety-nine percent of the people that die of myocardial infarctions, they have risk factors for cardiovascular disease.”

The idea of changing clocks was put forth by William Willett, a British builder. He came up with the concept in 1905 after observing that Londoners sleep through so many good hours of morning sunshine.

The latest study has been published in the New England Journal of Medicine.