Imagine waking up without needing an alarm. Sounds ideal, right? But for most of us, having an alarm is essential—especially since it’s often on our phones, leading to a doom-scrolling session before we’ve even brushed our teeth.

Still, it’s hard to believe that some people can naturally wake up before their alarm even goes off.

As someone who works shifts, I can confidently say that this isn’t an option for me. But for those who do, there’s actually a scientific explanation for it—one tied to the fascinating workings of the brain and body.

At the center of this mystery is a bundle of nerves called the suprachiasmatic nucleus, located in the brain. This group of nerves is like your body’s master clock, regulating blood pressure, body temperature, and, most importantly, your sense of time.

The suprachiasmatic nucleus determines when you feel tired or wide awake, so it’s the one to blame when you want a nap even after a full eight hours of sleep.

Your body’s internal clock thrives on routine, becoming more efficient when you go to bed and wake up at the same time every day. A protein called PER plays a key role in this process by regulating your sleep-wake cycle.