What happens to your body when you skip sleep?

When you skip sleep, your brain immediately starts struggling with focus, memory consolidation, and decision-making because neurons can't fire efficiently without rest. After just one night, cortisol and adrenaline spike, raising blood pressure and putting your cardiovascular system under stress. Your immune system produces fewer cytokines, making you more vulnerable to illness. Metabolically, hunger hormones like ghrelin increase while leptin drops, driving cravings for high-calorie foods. Reaction time slows to levels comparable to being legally drunk after about 17-19 hours awake. Extended sleep deprivation causes microsleeps, hallucinations, and cognitive collapse. Chronically skipping sleep is linked to increased risk of diabetes, heart disease, obesity, and even accelerated cellular aging.