Some people are still wired for two sleep periods

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Your body's natural schedule is based heavily on light, people used to wake up with the sun and sleep when it got dark. It's possible your body is on a similar system but with a delay, meaning instead of getting tired as soon as it's dark, it gets dark and then your body slowly starts getting tired. More likely, however, is that you're keeping the lights on too late and staring at your phone in bed and you aren't getting the morning sun to light up your room.

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