How does your body know when to wake up?

Your body knows when to wake up largely due to the circadian rhythm, a natural internal clock that regulates sleep-wake cycles over a 24-hour period. This rhythm is influenced by environmental cues, especially light exposure, which signals the brain to produce hormones like cortisol that promote alertness. Additionally, the body’s sleep cycles, including REM and non-REM stages, play a role in determining the optimal time to wake up, often leading to a natural awakening as sleep becomes lighter. Overall, a combination of biological processes and external factors helps regulate when you feel ready to wake up.