It accumulates in the brain and binds to specific receptors, decreasing alertness and suppressing the central nervous system.Īdenosine is unique, as these receptors are essentially 'cleaned out' during sleep, allowing the cycle to start all over again each day. Melatonin is generally only produced toward the end of the day when light levels are declining and you're ready for bed.Īdenosine, on the other hand, is constantly produced throughout the day. AdenosineĪdenosine is the other chemical necessary to normal circadian rhythm function, helping the body wind down at the end of the day. Those who have a hard time falling asleep may find success with melatonin supplements or drugs called melatonin agonists that work through this same pathway. When melatonin is secreted in the brain, typically with dusk and darkness, it attaches to receptors that help make you feel drowsy. Melatonin is a natural hormone secreted by the pineal gland in response to periods of darkness, helping to facilitate tiredness and make the transition into sleep easier.Ī region of the brain known as the suprachiasmatic nucleus (SCN) essentially acts as the circadian rhythm pacemaker, but it also takes information about ambient light levels and relays these messages to the pineal gland. The two primary chemicals involved in regulating the circadian rhythm are melatonin and adenosine. The circadian rhythm works through chemical messengers that regulate the many parts of the body synced to the internal clock. Over millions of years of evolution, the circadian rhythm in humans is closely tied to the light and darkness of day and night. The circadian rhythm controls when you get tired, when you wake up, how your body temperature changes, and even how your metabolism changes throughout the day.

The circadian rhythm describes your internal biological clock that loosely follows the 24-hour earth day. The circadian rhythm is your body’s internal alarm clock and bedtime signal, helping to coordinate all this and more based on a 24-hour cycle.īelow is a closer look at the circadian rhythm, how it works, common circadian rhythm problems, and ways you can support a healthy circadian rhythm and improve your sleep. Why do you get drowsy at night and wake up in the morning? It's all thanks to your master clock, the circadian rhythm. One bodily function that doesn’t get much attention until something goes awry is your natural ability to go to sleep and wake up.

Circadian rhythm wake up time