Setting clocks ahead one hour could accelerate cardiac events in certain individuals.
Researchers found a 25 percent increase in heart attack on the Monday after the clocks are turned forward compared to a regular Monday, a University of Michigan Health System news release reported. The team also noticed a 21 percent decrease in heart attacks the Monday after the clock are set back to standard time.
"What's interesting is that the total number of heart attacks didn't change the week after daylight saving time," lead investigator Amneet Sandhu, M.D., cardiology fellow, University of Colorado in Denver, and formerly worked at U-M, said in the news release. "But these events were much more frequent the Monday after the spring time change and then tapered off over the other days of the week. It may mean that people who are already vulnerable to heart disease may be at greater risk right after sudden time changes."
Monday mornings have been known to be prime time for heart attacks.
"Perhaps the reason we see more heart attacks on Monday mornings is a combination of factors, including the stress of starting a new work week and inherent changes in our sleep-wake cycle," Sandhu said. "With daylight saving time, all of this is compounded by one less hour of sleep. Whatever the reason, he said, the findings may indicate a need to better staff hospitals the Monday after setting our clocks forward.
"If we can identify days when there may be surges in heart attacks, we can be ready to better care for our patients," Sandhu said.
The hospitals included in the study admitted an average of 32 patients admitted for heart attacks on Mondays. The study adds to a "growing debate" that calls into question if daylight savings time is even still necessary.
"We go through daylight saving time periods twice yearly," Sandhu said. "We may want to look more closely at whether the shift in the timing of heart attacks seen after daylight saving time leads to any negative health outcomes."
The study only looked at patients in one state and did not take into account patients thad passed away before reaching the hospital.
