The Relationship Between Melatonin and Circadian Rhythm

While you’re busy going about your day, your circadian rhythm is quietly humming along, telling your brain when it’s time to be alert, and when sleepiness should start kicking in. Everyone’s rhythm is different. If you’re a night person, you may feel more tired at different times compared to a morning person. Most commonly though, the big energy dive occurs in the early hours of the morning while we’re typically already asleep, as well as around 1:00 p.m. and 3:00 p.m., often right after lunch. You can thank your natural circadian rhythm and melatonin secretion for this! But how does melatonin actually play into your circadian rhythm and your sleep/wake schedule? Let’s find out.

You and Your Hypothalamus

The hypothalamus is a part of the brain responsible for a lot of things. It controls many of the body’s regulations and controls, including body temperature, emotional responses, sexual behavior, and the release of 8 major hormones by the pituitary gland. One of these major hormones is melatonin, also known as the sleep hormone. Many think of melatonin as the magic ingredient to getting better sleep. But the process of how your body releases the hormone is finely tuned and can be easily disrupted, confusing your natural circadian rhythm.

Sleep/Wake Cycle

When you think of melatonin, think of the rising and setting of the sun. As we get exposed to more sun throughout the day, your body’s melatonin secretion drops off. And as it gets darker at night, that secretion increases again. Melatonin helps maintain the body’s circadian rhythm, that internal clock we all have running 24 hours per day. We can attribute our sleep/wake cycle to this process.

Disrupting the Cycle

Sometimes life makes it hard to keep our sleep/wake cycle on a healthy path. Things like jet lag, shift work, and even poor vision can disrupt the body’s normal melatonin cycle. Anything that causes us to get less light during the day, or too much of it at night, can cause major circadian rhythm issues. If you have bright lights on during your evenings at home, the secretion of melatonin will be delayed, resulting in you feeling more alert despite the time of day. There are a variety of lights, screen filters, and dimmers that can be implemented to counteract this.

Keeping a Healthy Rhythm

There are a few ways you can maintain a steady sleep/wake cycle so your internal clock never falls too far out of whack. Keeping a regular wake time and bedtime will reinforce the right times to stay alert and get sleepy. Late caffeine boosts and exercising too late in the day can get in the way of keeping a steady bedtime, so be mindful of these lifestyle habits as well. Avoid napping and try to stay somewhat active throughout the course your day. Get a decent amount of natural or bright light during the day, and avoid harsh lights in the evening, including blue light emitted from electronics.

Your circadian rhythm and the secretion of melatonin is a carefully balanced process that can often be disrupted without even knowing how or why. By staying aware of the effect that night, day, bright lights, and other factors have on the sleep/wake cycle, you can take steps to keep your internal clock on-time, and that means better sleep for you!

“Light, melatonin and the sleep-wake cycle.”Nationl Institutes of Health. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1188623/.
“Melatonin Overview”.University of Maryland Medical Center. https://www.umm.edu/health/medical/altmed/supplement/melatonin.
“4 Tips to Maximize Your Circadian Sleep-Wake Rhythm”.Sleep.org. https://sleep.org/articles/4-tips-maximize-circadian-rhythm/.
Published on: February 17th, 2018 by: Leah Perri

Last modified on March 21st, 2018



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