How Our Innate Sleep Cycle and Circadian Rhythm Have Powerful Effects On Our Overall Health
The sleep cycle and the circadian rhythm are fascinating parts of life on this planet we call Earth, almost all known life on earth has a twenty four hour pulse (circadian rhythm) literally built in to it’s cellular structure. This rhythm tells our bodies when it’s time to sleep and when it’s time to wake up. From the smallest bacteria all the way up to human beings, we are all “built” to function within cycles of light and dark. Incredible, but true. And within the 24 hour circadian rhythm, we sleep in definite sleep cycles which can measured within four distinct sections.
It is a proven scientific fact that circadian rhythms will even function when their typical cues or “zeitgebers” are removed completely, even when light and darkness are removed from our external environment our bodies will still show signs of cycling cortisol levels and core temperature. So , if a person was trapped in a cave for a week, their circadian rhythm would still function. It is a so called endogenous condition, as the sleep cycle is as well.
The Historical Beginnings of the Sleep Cycle and the Circadian Rhythm
Life is a circle, so they say, and that’s absolutely true especially when it comes to the sleep cycle and the circadian rhythm. These cycles are encoded into our DNA and in order to function properly we need to harmonize our lives with these cycles. At the beginning of earth’s history, photosensitive proteins within the earliest cells learned to protect themselves from mutation and ultraviolet radiation (the sun’s rays) through enacting protective measures on a 24 hour clock. This can be thought of as the beginnings of sleep, on a cellular level.
Five Distinct Stages Which Repeat Nightly To Restore Us
Our sleep cycle will occur within our circadian rhythm, cycles within a cycle. And within our sleep cycle, when our bodies are functioning normally, we will go through four stages. There are generally thought to be four stages of sleep, with a distinct and special fifth stage called REM sleep which appears on a shorter cycle. In order to function optimally and repair our bodies and minds on a nightly basis we need to cycle through all of these sleep cycle stages uninterrupted.
Stages 1 and 2 are lighter sleep stages somewhere between waking consciousness and deep sleep, stages 3 and 4 are considered deep sleep, and REM sleep is the dream state with it’s own special properties. The REM sleep state is very involved in memory and learning and the deep sleep stages, especially stage 4 sleep are involved in releasing important hormones.
Sleep Disorders Which Disturb the Sleep Cycle or the Circadian Rhythm
Unfortunately when we suffer from something like jet lag, for instance, our circadian rhythm is throw off, and when it is thrown off our sleep cycle will also likely be effected, very likely causing us to be fatigued, groggy, and stressed out because of lack of sleep. So, jet lag is a form of circadian rhythm disturbance, as are taking way to long to fall asleep and waking up well before sunlight and not being able to fall back asleep.
All of these problems will effect sleep cycles negatively. Also, anything which breaks a sleep cycle can effect our health in a negative way. Not having enough REM sleep or deep sleep (stages 3 and 4) will result in poor memory and lack of regeneration. There are many sleep disorders which break or interrupt our sleep cycles, good examples would be sleep apnea and restless leg syndrome.
However, even city noise and bright lights can slightly disturb the sleep cycle, which has subtle yet sometimes lastly effects on our health. It’s extremely important to practice good sleep hygiene and go to bed and wake up at roughly the same times each day, this is how our bodies function best. Paying attention to circadian rhythm and achieving deep sleep is a wonderful safe guard against some very serious health problems both in the short and long term.