Daylight-saving time is a killer. The annual ritual in which we "gain" an hour of evening light by pushing the clocks forward may seem like a harmless shift. But each year on the Monday after the springtime switch, hospitals report a 24% spike in heart-attack visits around the US.
Just a coincidence? Probably not. Doctors see the opposite trend in the fall: The day after we turn back the clocks, heart attack visits drop 21% as people enjoy a little extra pillow time.
"That's how fragile and susceptible your body is to even just one hour of lost sleep," sleep expert Matthew Walker, author of "How We Sleep," previously told Business Insider.
Walker said daylight-saving time, or DST, is a kind of "global experiment" we perform twice a year. And the results show just how sensitive our bodies are to the whims of changing schedules: In the fall the shift is a blessing; in the spring it's a fatal curse.
In addition to the heart-attack trend, which lasts about a day, researchers estimate that car crashes caused by drivers who were sleepy after clocks changed likely cost an 30 extra people in the US their lives over the nine-year period from 2002 to 2011.
The problems don't stop there. DST also causes more reports of injuries at work, more strokes, and may lead to a temporary increase in suicides. Our bodies may not fully recover from the springtime bump for weeks.