What Is Sleep Pressure? Your Sleep Debt Explained

Ever fought to keep your eyes open during an afternoon meeting, despite getting what you thought was a full night’s sleep? You’re experiencing sleep pressure—your body’s biological alarm system is telling you it’s time to power down.

Your brain tracks wakefulness by accumulating adenosine molecules—tiny chemical messengers that build up hour by hour like sand in an hourglass.

The longer you stay awake, the more adenosine collects, and the stronger your urge to sleep becomes.

This invisible force...