We spend approximately one-third of our lives unconscious, resting in bed. Yet, most people have very little idea what their bodies and brains actually do during those eight hours.
From sudden involuntary falling sensations to why yawns spread across a room, here are 7 bizarre, science-backed fun facts about human sleep biology.
1. That "Falling" Feeling Has a Name: The Hypnic Jerk
Have you ever felt like you were stepping off a cliff or falling from a building just as you drifted off, causing your entire body to twitch awake? This is called a Hypnic Jerk. It happens when your muscles relax so rapidly that your brain misinterprets the sudden drop in muscle tone as a sign that you are physically falling!
2. Contagious Yawning Is an Empathy Response
Seeing or hearing someone yawn triggers a mirror neuron response in your brain. Evolutionary scientists believe contagious yawning evolved as a social bonding mechanism to keep ancient human tribes synchronized in their sleep-wake schedules.
3. Humans Are the Only Mammals That Delay Sleep Intentionally
While animals go to sleep as soon as their bodies feel tired, humans are the only mammals on Earth that willingly push back sleep to watch videos, finish work, or socialize.
4. Your Body Is Taller in the Morning
During the day, gravity compresses the cartilage discs in your spine. While you lie flat in bed at night, your spine decompresses and rehydrates, making you up to 1 cm taller when you first wake up!
5. Dreaming Helps Cleanse Painful Memories
During REM sleep, your brain replays emotional memories while suppressing stress neurochemicals like noradrenaline. This allows you to process difficult experiences without feeling the original emotional pain, functioning like overnight therapy.
6. Color Dreams Were Rare During Black-and-White TV Era
Studies in the 1950s showed that over 80% of people who grew up watching black-and-white television reported dreaming in black-and-white! Today, with color screens everywhere, over 95% of people dream in full color.
7. You Can’t Sneeze While Sleeping
The brain signals that trigger sneezing are completely shut down during deep sleep. Even if dust or allergens enter your nose, your brain won't trigger a sneeze until after you wake up!
Optimizing Your Body for Rest
Understanding sleep biology helps us respect how much work our bodies perform at night. Giving your spine proper ergonomic support with an award-winning foundation like the Sonno Original Mattress or a contoured Sonno Memory Pillow gives your body the ideal environment to recharge.
To learn how to sync your daily routines with biological timing, read our complete guide on how to become more of a morning person.