Sleep deprivation is no joke. You can’t cheat sleep. Exhaustion is the most obvious symptom, but that’s only the tip of the iceberg. Turns out, you have a physiological need for sleep. Without it, your cells don’t function properly, you stress your heart, and you can have sleep deprivation hallucinations. Plus, when you’re tired, your brain doesn’t function correctly, making it harder to remember things and also making you accident prone.