Welcome to my blog. Here I help shift workers have more energy, stamina, get more sleep, and improve their diet while working shift work. I cover things like nutrition, exercise, sleep, mindfulness, and increase positivity. Today we are going to discuss your circadian rhythm, your biological clocks, and your master clock. Hopefully by the end, you will have a better understanding of each of these and be able to improve your sleep.
Circadian Rhythm
A circadian rhythm is a physical, mental, and behavioral change that follows a 24-hour cycle. These natural changes or “processes” respond primarily to light and dark and affect most living things, including animals, plants, and microbes. (Chronobiology is the study of circadian rhythms). One example of a light-related circadian rhythm is sleeping at night and being awake during the day. But how do these rhythms affect your health?
They can influence very important functions in our bodies. For example, Hormone release, eating habits and digestion, and body temperature. However, most people notice the circadian rhythm in their sleep patterns especially if you do shift work. The suprachiasmatic nucleus, or SCN, controls the production of melatonin in your body. The melatonin is what makes you sleepy. Basically, it receives information about light from the optic nerve in your eyes which sends a signal to your brain. The SCN tells the brain to make more melatonin, so you get more and more sleepy. This is what happens at night during shift work. Your body is producing melatonin and you are forcing yourself to stay awake and work. This has dramatic effects on the body.
I have heard people say that their bodies are “used” to working nights and it doesn’t affect them anymore, however, it’s not so much as they are “used” to working nights per se, it’s that their body has learned to adapt to the years of working nights. Your body makes and keeps its own circadian rhythm by important genes called the Period and Cryptochrome genes. These genes code for proteins that build up in the cell’s nucleus at night and lessen during the day. These proteins help activate feelings of wakefulness, alertness, and sleepiness. However, signals from the environment also affect circadian rhythms. For example, as stated above, exposure to light at a different time of day can reset when the body turns on Period and Cryptochrome genes. This is why it is crucial that you get to sleep within a certain time frame after working a night shift. You only have a small window of time before these genes reset your circadian rhythm and you are awake.
Biological Clocks
Biological clocks are organisms’ natural timing devices, regulating the cycle of circadian rhythms. They’re comprised of specific proteins that interact with cells throughout the body. Nearly every tissue and organ contain biological clocks. No, we are not talking about rushing out to have babies, we are talking about the fact that most organisms inherit the innate ability to keep track of time on a 24-h scale. For example, birds use their biological clock during migration to help compensate for the changing position of the sun throughout the day, chipmunks use an innate biological clock to properly time foraging to avoid predators, monarch butterflies use a circadian clock that participates in initiating migration by tracking seasonal changes.
Researchers have identified similar genes in people, fruit flies, mice, plants, fungi, and several other organisms that make up the “clocks” molecular components. However, research has shown that the biological clock is not equally sensitive to light at all times of the day as has been shown subsequently for many organisms that use light as an entraining signal. Light exposure in the early night produces a “phase-delay” shift (that is, the rhythm is delayed to a later hour). Light exposure in the late night produces a “phase-advance” shift (the rhythm is advanced to an earlier hour). Light during the day produces very small or no phase shifts at all. So, in other words the response to light is dependent on the organisms’ internal sense of time, and the magnitude and direction of these responses is dictated by the organisms own circadian phase when the light was presented.
According to the National Library of Medicine,
“Humans living in industrialized societies with widespread use of artificial light, round-the-clock jobs and social activities, and the ability to travel rapidly across time zones are often exposed to conditions in which their internal circadian rhythms become desynchronized from the experienced light–dark cycle. There is now increasing evidence that disruption of internal rhythmicity can have negative health outcomes in people, including insufficient sleep and the corresponding drowsiness and associated safety issues, increased susceptibility to immune challenges, increased risk of cardiovascular and metabolic disease, and increased cancer risk”.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6120700/
The biological clock of humans adapts slowly to the rapid transitions between different shift schedules. This will lead to a desynchrony or misalignment of the physiological system. This includes such things as sleep, alertness, performance, metabolism, and melatonin and cortisol levels. Research has shown an increased risk of certain cancers with hypothesized causal roles of light at night, melatonin suppression and circadian desynchrony.
Conclusion:
I know this particular topic was short and sweet, but I hope you got something out of it and learned something. As you can see here, sleep is very important in shift work. Some helpful tips are to limit the amount of light you’re exposed to after working a night shift. Try to get black out curtains and get to bed shortly after your shift to avoid the melatonin suppression. Please reach out to me if you need any help. I will be launching a course here in the near future for shift workers to improve their lives and make their schedule a little easier.
Until next time,
Darren
Harmony Shift 