Our sleep-wake cycle, related to the sun, is the most basic rhythm we all live by.
This and other daily patterns are a part of our circadian rhythm. The word circadian derives from ‘circum,’ meaning ‘around,’ and ‘dies,’ meaning “day.” Our circadian rhythms are governed by the body’s internal biological clock nestled deep within our brain.
Research has found that our body clock is responsible for much more than our sleep and wakefulness. Some of the other systems that operate on daily rhythms include hunger, mood, mental alertness, heart function, immunity, and stress.
Our biological clock is more apparent when it’s off-kilter. Shift work and jet lag are two examples of things that throw our everyday patterns out of whack. When daylight savings begins or ends, it profoundly impacts our circadian rhythm.
The idea of a biological clock is often considered a metaphor. Still, a very distinct brain region is in charge of keeping time. It’s the area called the SCN or suprachiasmatic nucleus, and it’s situated above the area of the brain where our optic nerve fibers cross. The location of the SCN enables it to receive cues from light in our environment to help it keep time.
Because our genes also influence our body’s clock and circadian rhythms, our system requires both input types – genes and light- to keep it on the right track. Our brain needs the input of sunlight through our eyes to reset itself every day to stay on the 24-hour cycle.
Melatonin is one of the hormones responsible for our regular cycle; when night falls, there is less natural light input to the SCN, which increases melatonin production. When it gets dark, even more melatonin gets secreted, signaling our brain that it’s time to go into sleep mode. As the sun rises, our body inhibits melatonin secretion, and we return to “wake mode.” This is one of the reasons it’s difficult for some people to work the night shift.
Many of our other systems follow a daily rhythm, controlled by hormones and other compounds. For instance, the hormones responsible for metabolism and hunger naturally rise and fall throughout the course of a day. Chemicals involved in our immune system function also vary. Compounds that encourage our body’s inflammatory response are elevated at night, so fevers spike at that time. The compounds that inhibit the inflammatory response boost during the day.
Paying attention to our body’s natural rhythms is more critical to our health than many realize. It isn’t merely sleep deprivation but the alteration of our biological rhythms that interferes with various body functions. In turn, these disruptions cause us to be more prone to health issues like mood issues, infections, and heart disease.
You likely have a good sense of your own body’s natural rhythms, so try to avoid disruptions to your eat-sleep cycles and practice good sleep hygiene. Stick to a regular schedule that works well for your system’s natural rhythm. This might include heading to bed a little earlier, cutting back on caffeine later in the day, and limiting your screen time before bed. These little tips can significantly impact how our internal clock functions and how we feel overall.