What happens to your body when you don't sleep enough?

When you don't get enough sleep, your body and brain suffer in multiple ways. Cognitively, you experience impaired concentration, slower reaction times, poor decision-making, and memory problems. Your immune system weakens, making you more vulnerable to illness. Hormones are disrupted, including increased cortisol (stress hormone) and ghrelin (hunger hormone), which drives overeating and weight gain, while leptin, which signals fullness, drops. Physically, chronic sleep deprivation raises blood pressure, increases inflammation, and elevates the risk of heart disease, diabetes, and stroke. Your body also produces less growth hormone, which is essential for tissue repair. Even a few nights of poor sleep can impair your body similarly to being legally drunk, affecting coordination and judgment significantly.