The circadian rhythm is an internally regulated biological process, also known as the internal clock. Derived from the Latin words “circa,” meaning “around,” and “diem,” meaning “day,” it refers to the roughly 24-hour cycle that impacts various bodily functions, such as sleep patterns, hormone production, body temperature, and alertness.
You can see circadian rhythms as internal timetables that are present in every single cell, in every organ in our body, including the brain and responds to the environment. The cells of the body respond to environmental conditions, such as light or dark, and rely on signals from the body to give to the brain. These signals help determine whether you feel sleepy or awake. Circadian rhythms are regulated by a circadian clock whose primary function is to rhythmically co-ordinate biological processes, so they occur at the right time to maximize the fitness of an individual.
Hormones such as cortisol and melatonin are also linked to the circadian rhythm. Their production may increase or decrease according to the circadian rhythm and environmental conditions. Melatonin is the hormone that makes you feel sleepy, which you need in the evening and during the night. Cortisol is the hormone that makes you feel more alert, which you need during the day. The suprachiasmatic nucleus (SCN) in the brain acts as the master clock, synchronizing the circadian rhythm with external environmental cues, primarily light and darkness. This makes the production of these hormones highly influenced by the environmental factors like light & dark.
It’s all about receiving sunlight in your eyes (don’t look right into the sun) in the morning. Receiving morning sunlight directly in the eyes provides a signal from the retina to the biological clock. Your body responds by blocking melatonin and starting cortisol. Cortisol will release sugars from the liver and muscles to start your day with energy. Exposing yourself to sunlight early in the morning will make you feel energized, just as dimming the lights and limiting blue lights in the evening will help you feel sleepy.
These timely activities in your body help you to prevent disease and improve your immune function to better fight infectious disease. They also optimize brain function to improve your emotional and intellectual health and accelerate repair mechanisms to help you recover from injuries faster.
Sleep is probably the most important recovery strategy for your body. Another reason why supporting your circadian rhythm is so important is that a healthy circadian rhythm translates to good sleep, and good sleep promotes healing, consolidates memories, and cleanses the brain.
Understanding and respecting your body’s internal clock is not just about getting a good night’s sleep; it’s about nurturing your overall health and unlocking your full potential for productivity and well-being. When you take care of your circadian rhythms, everything in your body and brain falls into place. Even when you get sick, nurturing your circadian rhythm can be your secret power.
Tips to optimize your circadian rhythm and maximize quality sleep:
1. Expose yourself to sunlight in the morning. Your body will respond to these natural light cues and regulate your circadian rhythm and associated hormones.
2. Limit exposure to bright and blue lights in the evening. Blue light mimics sunlight and tricks your body into thinking it should stay awake. This causes a reduction in the production of melatonin, your sleep hormone, leading to poor sleep quality and less alertness the next day. The more blue light you get, the less alert you are during the day.
3. Keep a consistent sleep schedule. Maintaining sleeping and waking times within about a ninety-minute window helps regulate your circadian rhythm.
4. Create a consistent bedtime routine to help your body wind down towards bedtime.
5. Eat your last meal at least 2-3 hours before bedtime. Avoiding late-night snacking can help your body align with the natural light and dark cycles and may also reduce your blood sugar the next day.
6. Don’t drink alcohol or caffeine in the evening. Try to cut out caffeine consumption before noon, especially if you have any trouble sleeping.
7. Go outdoors. Being outdoors for 30 to 60 minutes in daylight, even on a cloudy day, is the best way to re-synchronize your brain clock and improve your mood.