Study finds less sleep at time change might harm the heart

“Sleep is very important for the regenerative process and getting the heart rested. You can’t run an engine all the time. You need to relax a little bit. At night, that’s when your heart rate goes down and your blood

pressure goes down.”

Dr. Nilay Mehta, a cardiologist at Memorial Hermann

Feeling tired isn’t the only risk associated with the return of daylight saving time Sunday — one study found that setting your clock forward could be bad for your heart.

The study, published in 2014 in the journal Open Heart, found a 24 percent increase in heart attacks on the Monday after losing an hour of sleep in the spring. It also found a 21 percent decrease in heart attacks on the Tuesday after gaining an hour of sleep in the fall.

Prior studies have found that heart attacks are more common on Mondays, which experts attribute to factors such as the stress of returning to work for a long week ahead. Losing an hour of sleep adds to the risk because other studies have found that poor sleep habits affect heart health.

Many people don’t get enough sleep in general, and losing an hour because of the spring time change compounds the problem, said Dr. Nilay Mehta, a cardiologist at Memorial Hermann.

“You’re losing that hour of sleep, and sometimes people don’t have the amount of sleep they require anyway,” he said. “That’s obviously a stressor.”

The overall risk of suffering a heart attack after a time change is not high, though the stress that comes with losing an hour of sleep can be detrimental for someone with a heart condition, Mehta said. However, he said the study speaks to the importance of getting enough sleep in general and of sticking to a regular sleep schedule as much as possible.

Adults who sleep less than seven hours per night on average are more likely to report health problems such as heart attacks, asthma and depression, according to the U.S. Centers for Disease Control and Prevention.

“Sleep is very important for the regenerative process and getting the heart rested. You can’t run an engine all the time. You need to relax a little bit,” Mehta said. “At night, that’s when your heart rate goes down and your blood pressure goes down.”

Heart attacks aren’t the only risk associated with daylight saving time. Another study, published last year in the Journal of the American Heart Association, found that the overall rate of ischemic strokes in Finland was 8 percent higher in the two days after a time change.

University of Michigan researchers led the 2014 study that focused on heart attacks. They looked at admissions to Michigan hospitals between spring 2010 and fall 2013.

The hospitals included in the study typically admitted an average of 31 heart attack patients per day. Admissions increased by nearly eight per day on the Monday after a spring time change and fell by more than seven on the Tuesday after a fall time change, according to the study.

There were no other significant changes in any other weekdays after daylight saving time.

The study does have limitations. It includes hospitals from just one state and does not include anyone who had a heart attack but died before reaching a hospital.

Mehta suggests easing into Sunday night by going to sleep a bit earlier — perhaps 15 minutes per night beginning Thursday — to prepare for the time change.

“You’re slowly kind of transitioning yourself into that (lost) hour so you’re not as sleep deprived when you do lose that hour,” he said.