It seems like moving the clock ahead just one hour shouldn’t make a big difference—but the science says otherwise.

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1. The transition may briefly increase your risk of stroke. 
A recent study from Finland, to be presented at the American Academy of Neurology's 68th Annual Meeting, showed that in the two days following a clock change (either in the fall or spring), the overall risk of stroke rose by 8 percent. While Daylight Saving Time is certainly not the only risk factor, doctors speculate that the change in circadian rhythm affects those who are already at-risk for an ischemic stroke, the most common type caused by a blockage in blood flow to the brain.

2. You’re not being dramatic—it does mess with your sleep cycle.
It took 29 percent of Americans a full week to feel normal again after losing an hour of sleep, according to a February 2014 survey from the Better Sleep Council. What’s more, 12 percent forgot to do something important and 5 percent said they acted irrationally—including “got in shower still wearing underwear” and “went to work on a day off.” 

3. It might affect heart health.
A 2012 study showed that heart attack risk increased 10 percent the Monday and Tuesday following the beginning of Daylight Saving Time. The health risk was tied to sleep deprivation, a change in circadian rhythms, and a slight shock to the immune system due to the time change.

4. You’re more likely get injured on the job.
A 2009 study published in the Journal of Applied Psychology studied mine workers, and found that they experienced 5 percent more workplace injuries when the clocks sprang forward, an effect that researchers tied to lack of sleep. Of course, this environment is riskier than your typical office job—but beware of the stapler.

5. If you like staying up late, you might take a hit.  
A German study published in the journal Sleep Medicine found “daytime sleepiness” was higher in people who identified as “evening types”—or what we call “night owls.” The study found that it could take up to three weeks for them to adjust to the time change.

6. Roads become unsafe.
Some research has shown that fatal car accidents increase the Monday after we lose an hour, likely due to sleep deprivation. 

7. You’re not a good sleeper after losing an hour.
In fact, researchers from the National Public Health Institute found that the transition to spring reduced sleep efficiency (how long you spend in bed compared to how long you actually spend sleeping) by 10 percent on average. 

8. You’ll spend more time glued to the computer.
It’s called “cyberloafing,” and researchers from Penn State found that losing just 40 minutes of sleep has been correlated to an increase in surfing the web, checking Facebook, and more unproductive activity. In fact, entertainment-related Internet searches spike the Monday after the beginning of daylight saving time, compared to other Mondays before and after.

Plus, find out how Daylight Saving Time affects your child's sleep, and what you can do to help him or her through the transition.