Editor's Note: This story contains one of our 11 New Years resolutions you can actually keep in 2014. For the full list, click here.
It may seem like a superpower to be able to wake up without an alarm, but it's more attainable than you think. It's really just regular ol' biology—the result of your hormones getting you ready for the day.
As Lucas Reilly writes at mental_floss, your body's circadian rhythms are governed by the suprachiasmatic nucleus, a clump of nerves in the center of your brain that tells you when to feel tired and when to feel awake. The key word here is rhythm: the more consistent your sleeping and waking times, the more readily you'll sleep and wake, thanks to a protein called PERIOD (or just PER).
The number of PER proteins in our cells goes up and down through the day. In the evening, PER levels go down and our systems relax accordingly, as blood pressure, heart rate, and mental processes all begin to wind down. As the morning approaches, your PER levels go up, raising your body temperature and blood pressure. In addition, mobilization (usually called "stress") hormones like cortisol start releasing into your body, weaning you out of slumber and into the activity of the day.
But when you're woken suddenly by an alarm clock, you don't experience the gradual ease of being awoken by your natural sleep cycle; instead you're groggy and stumbling—symptoms of sleep inertia.
A University of Lubeck study where 15 volunteers were asked to sleep in a lab for three nights, proved this. As Reilly writes, the results were, well, jarring:
One night, the group was told they'd be woken at 6 a.m., while on other nights the group was told they’d be woken at 9 a.m.
But the researchers lied—they woke the volunteers at 6 a.m anyway. And the results were startling. The days when sleepers were told they'd wake up early, their stress hormones increased at 4:30 a.m., as if they were anticipating an early morning. When the sleepers were told they’d wake up at 9 a.m., their stress hormones didn’t increase—and they woke up groggier.
In other words, it seems that our bodies can sense the intent we set for waking. This is why diligently keeping a rhythm is so helpful: If we set a time to sleep and wake for every day, then our relaxation and mobilization proteins and hormones can start to activate accordingly. If you do it with a consistent enough rhythm, you may not need that alarm clock after all.
For similar reasons, your snooze button is a deceitful bastard. When you first wake up, your body is coursing with mobilization hormones, but putting your head back on the pillow tells your body to relax again. Which confuses what could be a clear morning routine.
And if you're sleeping through your alarm, you might wanna work on your sleep hygiene.
Hat tip: mental_floss