When our clocks spring forward, people lose sleep, have more heart attacks, and might not even save energy

Groggier than usual? No surprise there: Americans set their clocks ahead by an hour yesterday and lost an hour of sleep. "Springing forward" creates another hour of sunlight in the evening. It also has some effects on health and public safety that many people are unaware of. Interesting facts about daylight saving time include:

1. Officially, it's "daylight saving time," not "daylight savings time." But don't feel bad if you thought there was a final "s" on "saving"; far more people Google the incorrect phrase than the correct one.

2. Daylight saving time has mixed effects on people's health. Transitions into and out of DST can disturb people's sleeping patterns, for example, and make them more restless at night. Night owls tend to be more bothered by the time changes than people who like mornings, Finnish researchers concluded in 2008.

3. There's a spike in heart attacks during the first week of daylight saving time, according to another study published in 2008. The loss of an hour's sleep may make people more susceptible to an attack, some experts say. When daylight saving time ends in the fall, heart attacks briefly become less frequent than usual.

Still tired?  See the full list of 12 things you don't know about Daylight Saving Time here.