PhotoThe clocks move forward one hour on March 11, as most of the U.S. goes on Daylight Savings time. In addition to arriving early at appointments if you forget to reset your clocks, you could be at greater risk for a heart attack.

“The Monday and Tuesday after moving the clocks ahead one hour in March is associated with a 10 percent increase in the risk of having a heart attack,” said Martin Young, an associate professor at the University of Alabama Birmingham (UAB). “The opposite is true when falling back in October. This risk decreases by about 10 percent.”

The Sunday morning of the time change doesn’t require an abrupt schedule change, but, Young says, heart-attack risk peaks on Monday when most people rise earlier to go to work.

A number of theories

“Exactly why this happens is not known but there are several theories,” Young says. “Sleep deprivation, the body’s circadian clock and immune responses all can come into play when considering reasons that changing the time by an hour can be detrimental to someone’s health.”

Why is losing an hour of sleep risky? Young says people who are sleep-deprived also tend to suffer more from diabetes and heart disease.

“Sleep deprivation also can alter other body processes, including inflammatory response, which can contribute to a heart attack,” Young said.

And, your reaction to sleep deprivation and the time change also depends on whether you are a morning person or night owl. Night owls have a much more difficult time with springing forward.

Circadian clock

You says every cell in the body has its own clock that allows it to anticipate when something is going to happen and prepare for it. When there is a shift in one’s environment, such as springing forward, it takes a while for the cells to readjust.

“It’s comparable to knowing that you have a meeting at 2 p.m. and having time to prepare your presentation instead of being told at the last minute and not being able to prepare,” he said. “The internal clocks in each cell can prepare it for stress or a stimulus. When time moves forward, cell clocks are anticipating another hour to sleep that they won’t get, and the negative impact of the stress worsens; it has a much more detrimental effect on the body.”


Fortunately, there are ways to counterbalance the negative aspects of the time change. Young suggests waking up earlier on Saturday and Sunday than you need to in preparation for the early start on Monday. Eat a good-sized breakfast and get exposure to sunlight early in the day. If healthy enough to exercise, do so over the weekend.

“Doing all of this will help reset both the central, or master, clock in the brain that reacts to changes in light/dark cycles, and the peripheral clocks — the ones everywhere else including the one in the heart — that react to food intake and physical activity,” Young said. “This will enable your body to naturally synch with the change in the environment, which may lessen your chance of adverse health issues on Monday.”

Share your Comments