The Sleep-Wake Cycle

Understanding your internal clock
You’ve heard the term “biological clock.” It’s not just an abstract expression—there really is a specific area of the brain that’s responsible for regulating bodily functions that relate to timing. This area is often called the body’s “internal clock.” Doctors refer to it as the circadian rhythm.

The sleep-wake cycle regulates sleep

The master clock regulates many things in your body
Heart activity, body temperature, and hormone secretion are just a few of the master clock’s responsibilities. But the most familiar is the sleep-wake cycle. The sleep-wake cycle is what makes us feel alert during the day and sleepy at night. It’s your body’s way of adapting to the daily cycle of light and dark as the Earth rotates every 24 hours.

Disruptions can bring about insomnia

Disrupting the sleep-wake cycle
We live in a 24-hour society. Some of us regularly work night shifts, pull “all-nighters,” or travel across several time zones in one day. And if you’ve ever felt sleepy or groggy after doing one of these things, it’s because there’s been a disruption to your sleep-wake cycle. Your body thinks it’s one time when the outside world says it’s another.

Disruptions to the sleep-wake cycle, whether brought on voluntarily or by other issues like everyday stress or illness, can bring about insomnia. Fortunately, there’s Rozerem. Learn more about how Rozerem works with your body’s normal sleep-wake cycle to help you fall asleep.

Rozerem is approved for adults having trouble falling asleep.

Important Safety Information
Don’t take Rozerem if you’re taking LUVOX® (fluvoxamine) or have severe liver problems. Avoid taking it with alcohol. Don’t drive or operate machinery until you know how you’ll react to Rozerem. Rozerem may affect testosterone and prolactin. Consult your doctor if you have concerns about a change in your period, libido, fertility, or if your insomnia doesn’t improve. Take Rozerem right before bed. Side effects may include drowsiness, fatigue, and dizziness.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch, or call 1-800-FDA-1088.


If you need help paying for prescription medicines, you may be eligible for assistance. Call 1-888-4PPA-NOW (1-888-477-2669) or go to www.pparx.org.

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