Sleep Cycles and Stages Explained: Why You Feel Like a Zombie Without Them Ever wake up feeling like a bus hit you... even after a full night's sleep? (No? Just me? Cool.) Well, it might not be how long you slept — but how well you cycled through the glorious symphony known as your sleep stages . Let's break it down, nice and easy. No snoozefest science lecture here — just the good stuff. What Are Sleep Cycles, Anyway? Picture sleep as a VIP concert. You can’t just walk in, hear one song, and bounce. You have to go through all the acts: warm-up bands (light sleep), headliner (deep sleep), encore ( REM dreamland ). Each night, your brain shuffles through 4 main stages in about 90-minute cycles , and it repeats this set list 4–6 times before your alarm screeches at you. If the set gets interrupted (thanks, noisy neighbors or late-night TikTok scrolling), your body misses key parts of the show — and that’s when you wake up feeling awful. Meet the Sleep Stages: Your Bod...