What controls circadian rhythm?
Your circadian rhythm (sleep-wake cycle) is most heavily influenced by light in your surrounding environment, but can also be affected by temperature, physical activity, and social interactions. When your body’s internal clock isn’t synchronized with these external cues, you may feel sleepy but still have trouble sleeping.
Your biological clock
There are many parts of your brain that pick up on these external cues like sunlight, which then initiate signals to be sent to a brain structure called the suprachiasmatic nucleus (SCN). The SCN uses this information to control many different processes in your body, such as digestion, hormone regulation, body temperature, and sleep.
Medically reviewed by
Dr. Colleen Ehrnstrom is a licensed clinical psychologist with a specialty practice in Acceptance and Commitment Therapy (ACT). Areas of expertise include insomnia and other sleep disorders, anxiety, and depression.
Dr. Ehrnstrom is not a medical provider and is not providing any recommendations regarding medications. Rather, she is sharing and reviewing the research as it relates to education when learning how best to treat insomnia.