How your body knows when to wake up from sleep: The circadian rhythm explained

Ever wondered how your body seems to know it’s time to wake up, even before your alarm rings? That’s not luck, it’s biology. Deep within your brain, an intricate timekeeping system quietly regulates your sleep and wake cycles, adjusting to light, temperature, and daily habits. This internal rhythm determines when you feel alert in the morning and drowsy at night, shaping everything from your mood to your metabolism. A peer-reviewed study published in Frontiers in Neuroscience (2022) explained how the body’s master clock, located in a brain region called the suprachiasmatic nucleus (SCN), synchronises with light cues from the environment to control sleep and wake timing. Researchers found that specialised light-sensitive cells in the retina send direct signals to the SCN, allowing it t