How To Understand Your Circadian Rhythm and Sleep More
After a busy day of work, you naturally start to yawn and feel sleepy when the sun goes down. But have you ever noticed that even if you’ve stayed inside and binge-watched your favorite new series, you still find yourself yawning at sundown, despite the fact that you only moved between the couch and refrigerator? Why is that?
We feel most energized in the morning and drowsy at night because all human beings share the fact that we have an internal clock that is set to run on a roughly 24-hour rhythm. In fact, all life on the planet follows this same 24-hour cycle, including plants, animals, fungi, and bacteria. This master clock regulates our sleepiness, alertness, and even the times of day we are most likely to eat. In humans, our lowest energy levels occur between 2 and 4 am, the middle of the night, when we are most likely to be asleep. Our energy level also dips slightly between 1 and 3 pm, or after lunch, when we often crave a nap.
Our internal clock is regulated by the hypothalamus portion of our brains and primarily responds to external cues, especially daylight. When the light lessens at the end of the day our eyes send a signal to our brain to begin to release melatonin, the sleep hormone, and thus your eyelids may begin to feel heavy, and you will find yourself yawning and longing for sleep.
This is how our bodies are programmed to respond in a 24-hour cycle of light and dark. But what happens when this normal pattern of our master clock is altered by life events such as working a night shift, traveling across time zones, and even daylight savings time?
Effects of Outside Influences On Circadian Rhythm
We humans first began to subtly alter our natural circadian rhythms with technologies such as artificial lighting and alarm clocks. In 2017, three American researchers received the Nobel prize for a study on circadian rhythms which indicated that bright, blue-toned light had the greatest impact on preventing our master clock from releasing melatonin, whereas yellow or red lighting, such as from firelight, had very little effect on melatonin production and sleepiness.
These subtle alterations in our following of the natural circadian rhythm of our bodies have been more significantly altered in recent decades by the ability to travel across multiple time zones, as well as the necessity of working in bright lights for night shift workers and nighttime medical personnel. How do these unnatural alterations affect us?
A study by the University of Colorado has shown that interfering in our circadian rhythms on a regular basis can cause more harm than just some drowsiness, yawning, and lowering of our work performances. Altering our natural sleep/wake patterns can contribute to long term health problems. Some of the hormones regulated by our master clock are stress hormones, such as cortisol, and can contribute to heart problems. Three times as many heart attacks occur during morning and midday hours than in evening and night hours for this reason.
According to Dr. Richard Stevens, a professor at the University of Connecticut School of Medicine, melatonin has been shown to reduce incidents of breast cancer in mice. This is providing mounting evidence that reducing the hours of melatonin release in humans could be contributing to higher rates of breast cancer in today’s society.
Interfering with our biologically normal patterns of sleeping and waking has also been shown to contribute to depression and insomnia, as well as directly affecting mood and alertness.
How Can We Limit Interference In Our Natural Circadian Rhythm?
• Limit the amount of light you are exposed to during evening hours. When the sun goes down, you should consider switching from bright (LED) lighting to soft yellow light that mimics fire or candlelight.• Reduce screen time! Increasing the distance between the eye and the light source decreases the impact on your circadian rhythm. Watching a television across a candlelit room will not affect melatonin production nearly as much as holding an iPhone eight inches from your face.• Slowly alter your sleep patterns to fit a new time zone during the few days before taking a trip across time zones to avoid jet lag, which is a direct result of the sudden change in light patterns away from the programming of your master clock.• Temperature can also play a role in our circadian rhythm. We’ve all experienced the manner in which cooler temperatures can invigorate and increase alertness, whereas being warm and cozy will promote relaxation and sleepiness. It is helpful to your circadian rhythm to seek warmth and comfort during evening hours.
Just as many people have recently found that eating a diet more closely resembling that of our pre-technological ancestors is beneficial to our health, it also appears highly likely that mimicking the natural sleep/wake patterns of humans who existed before the invention of artificial lighting can also alter our health status in many positive ways.