Scientific American presents Everyday Einstein by Quick & Dirty Tips. Scientific American and Quick & Dirty Tips are both Macmillan companies.

Hi I’m Dr. Sabrina Stierwalt, the Everyday Einstein, bringing you Quick and Dirty Tips to help you make sense of science.

As an astrophysicist, I am happiest when I am at a telescope observing distant galaxies. My happiness is not just because I’m gathering data to further my research, but also because my body and mind feel their best at night. But that's not the case for everyone. I know plenty of folks who functon best in the early morning.

Do we learn our sleep patterns or are they hard-wired in us from the start? Are there real biological differences between early risers and night owls? Let's find out.

Are Night Owls Born or Raised?
Scientists have long believed that our preferred sleep patterns (called our “chronotypes”) are genetically determined at birth. After all, it makes evolutionary sense for people to have varied sleep schedules. Someone needs to guard the cave at night!

I can also tell you from firsthand night owl experience that living with an early riser has made caring for our infant much easier. There is never a question of who should get up with her in the middle of the night versus the early morning. (Dibs on the night!)

Our preferences for early riser versus night owl behavior are encoded in genes called “clock” or “period” genes that regulate our circadian rhythms and are thus linked to our blood pressure, metabolism, body temperature, and hormone levels. Studies have shown links between the length of certain period genes and people’s chronotypes, as well as the amount of sleep they need per night.

Environmental cues like light and diet (called “zeitgebers”) can work to alter our body’s sleep clock. Anyone who has taken an overnight flight knows the groggy feeling of jet lag upon landing. Your body feels like it's 3am while the sunrise outside tells your brain something different. The glow of our tablets, smartphones, and televisions is enough to delay the body’s nightly release of melatonin, the brain’s message that it is time for sleep.  

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