Circadian rhythms are like your own personal assistant that lets you know what you should be doing or how you should be feeling. These are 24-hour cycles that are part of the body’s internal clock, running in the background that tells the body when to sleep, wake, and eat—the biological and psychological processes that oscillate in predictable patterns each day. This internal clock is influenced by external cues, like sunlight and temperature, which help determine whether one feels energized or exhausted at different times of the day. One of the most important and well-known circadian rhythm cycles is the sleep-wake cycle. Circadian rhythms exist in all types of organisms. For example, they help flowers open and close at the right time and keep nocturnal animals from leaving their shelter during the daytime when they would be exposed to more predators.
Circadian rhythms are governed by a master clock, a group of neurons called the suprachiasmatic nucleus, located in a region of the brain called the hypothalamus. This master clock translates cues from the environment into directives for the body. This master clock is directly influenced by environmental cues, especially light, which is why circadian rhythms are tied to the cycle of day and night. Cues like this can then can affect the levels of certain Hormones in the body like melatonin and cortisol. Melatonin is a hormone that makes you sleepy, and your body releases more of it at night and suppresses it during the day. Cortisol can make you more alert, and your body produces more of it in the morning.
Another important property of the circadian rhythm is the strength of rhythm. If people have a strong consistant circadian rhythm, you really get that intrinsic sense of there are periods in the day when you feel alert, energetic and couldn’t sleep and other periods in the day when you feel really sleepy and no matter what, you couldn’t even stay awake even if you tried. When your circadian rhythm is healthy and properly aligned, it can promote consistent and restorative sleep. But when this circadian rhythm is thrown off, it can create significant sleeping problems, including insomnia. Research is also revealing that circadian rhythms play an integral role in diverse aspects of physical and mental health.
How To Maintain a Healthy Circadian Rhythm
While we don’t have full control over our circadian rhythm, there are healthy tips that can be taken to try to better entrain our 24-hour sleep cycles.
- Spend some time in the sun: Exposure to natural light, especially early in the day, helps reinforce the strongest circadian cue.
- Try to adhere to a routine each day. Varying your bedtime or morning wake-up time can hinder your body’s ability to adjust to a stable circadian rhythm.
- Get enough daily exercise. It is recommended that you try and get at least twenty or more minutes of aerobic exercise a day. Activity during the day can support your internal clock and help make it easier to fall asleep at night.
- Avoid alcohol, caffeine, and nicotine in the evenings. Stimulants like caffeine can keep you awake and throw off the natural balance between sleep and wakefulness. Everyone is different, but if you’re having trouble sleeping, you should avoid caffeine afternoon.
- Limit the ammount of light before bed: Artificial light exposure at night can interfere with circadian rhythm. Take this time before bed to really wind down by dimming the lights and putting down electronic devices in the lead-up to bedtime and keeping electronics out of the bedroom and away from your sleeping surface.
- Keep naps short and early in the afternoon: Late and long naps can push back your bedtime and throw your sleep schedule off-kilter.
- Sleep in an environment that promotes rest with proper lighting, a comfortable temperature, and a supportive mattress.
These steps can be taken to help support a healthy circadian rhythm, but other steps may be necessary depending on the situation. Generally, people who are in good physical health, good mental health, not taking any medications, maintaining a regular routine and being physically active will have a type of strong circadian rhythm.