Chronobiology and your circadian rhythm

Chronobiology and your circadian rhythm

November 29, 2020 0 By Rick

Chronobiology was a new term for me until I read “The Power of When,” by Dr. Michael Breus. I’m sure you’ve heard the expressions night owl and early bird. Well, Dr. Breus expands this concept into four different “chronotypes”: Dolphins, Lions, Bears and Wolves (more about these later). Are you more productive in the morning or much later in the day? Once you’ve identified your chronotype, you’ll be surprised at how much more this can affect you aside from prompting you to go to bed at night and get up in the morning. You might also be surprised to find that your body contains several “clocks” that help keep everything running smoothly. But there’s one “biggie” that drives your circadian rhythm, which controls things like your body temperature, hunger and sleep. And that internal clock is connected directly to your eyes, so light has a big effect on it. It’s called the circadian clock.

A biological clock
The circadian system, also known as your biological clock, affects every area of functioning in your body from the multiplication of cancer cells to the integrity of your immune system. This is the biological clock we have which controls our sleep-wake cycle, the release of hormones at important intervals, body temperature, blood pressure, and other critical mechanisms, to maintain homeostasis or balance. It seems that all life has this internal clock that falls in line with the Earth’s rotation and helps us adapt to changing aspects of the day and environment. All life as well as plant an animal behavior responds to the sun, i.e., is determined by the light-dark cycle. You might call us “slaves” to the sun. The circadian clock is a core feature for understanding life. So, let’s take a closer look at this all-important clock and how it affects us.

As soon as you open your eyes in the morning, light prompts your brain to turn certain genes on and certain genes off to fire you up for the day. Light also signals your brain to stop producing melatonin – the “sleepy” hormone. As day gradually turns to night, your melatonin production commences again to get you ready for sleep. Although our clocks seem to run on the same schedule for most of us, there are outliers that sometimes baffle us. You know, the people that jump out of bed, fully alert and primed for action and the people that you literally must drag out of bed. Let’s take a closer look at Dr. Breus’ chronotypes.

(15-20% of the population) are super productive early in the morning and up to mid-afternoon and then seem to crash. They often turn in early at night, which causes their social life to suffer in many cases. Their key personality traits are conscientiousness, stability, practicality and optimism. Wolves (15-20% of the population), on the other hand, start off slowly, get increasingly more productive as the day goes on and are really rolling as evening approaches. They seem to be able to party all night. Their key personality traits are impulsiveness, pessimism, creativity and moodiness. Most of us fall somewhere in between these two extremes and are Dolphins (10% of the population) with key personality traits such as cautiousness, introversion, neuroticism and intelligence. Bears (50% of the population) with key personality traits such as cautiousness, extroversion, friendly/easy to talk to and open-minded. And there are hybrids, of course. If you’re wondering why that is, Scientists think these variations have to do with the “speed” of your internal circadian clock – Lions have slightly faster clocks while Wolves have slower ones. It really doesn’t matter what the speed of your clock is, the trick is to work with your clock and not against it.

Our bodies need routine
Remember your university days when you pulled several all-nighters to make up for the studying you should have done instead of partying? If you were like me, you thought you could make up any sleep you lost on the weekend. How did that work out for you? Not only did I “lose” a weekend, but I felt like crap when I did get up. That’s because our bodies need routine, and the best way to get that is to get up and go to bed at the same times every day. There’s a reason why sleep deprivation is used in military training (and other areas, interrogations, for example) to push people to and sometimes past their limits. Ask me, I know. During Hell Week in BUD/S, we got 4 hours of sleep in 5 ½ days. And we didn’t get it all at once, either! Talk about zombies.

Front-loading food Our circadian rhythm even affects our eating habits and weight loss, according to nutritionist and author Tamara Duker Freuman, who has developed a meal-timing based plan she describes as the “circadian-synced diet.” Research has shown that when you front-load your calories (eating most of your calories early in the day), you have a much better chance of making those unwanted kilos disappear. “What we’ve seen is that people on diets with the same number of calories who front-load calories to the earlier part of the day fare better in terms of subjective and objective measures of satiety,” Freuman says. “They feel more satiated in evening, and there are actually differences in their hunger and satiety hormones … and this seems to contribute to weight loss success.” But wait, there’s more.

Healthy cellular function
Researchers at the University of Zürich discovered in a study that our circadian rhythm regulates protein transcription. “When you’re feeling tired and head off to bed, the proteins necessary for healthy cellular functioning are produced, peaking at two points in the day: right before bed and upon waking up. Sleep sets into motion the transcripts for protein-building, while waking up promotes synapse-firing, the communications device that allows neurons to speak,” according to the researchers. What can we take away from this? Honoring our circadian rhythm (getting seven-to-nine hours of sleep works for most people) promotes the  optimal building of proteins and communication between neurons. If you deprive yourself of sleep, you’ll not only be tired but your mental health will end up paying a steep price over time.

Circadian rhythm and disease
We’re becoming increasingly aware that the more we get divorced from our circadian rhythm, the more we run the risk of getting sick. That’s right, your immune system can be affected, too. Some studies have demonstrated a link between messed-up circadian rhythms and cancer, diabetes, bipolar disorder and even obesity. Researchers have found that circadian rhythms can influence the treatment of disease. Apparently, even the time of day you have surgery or take a medication plays a role. Moreover, some scientists believe that our circadian rhythms may also influence the treatment of disease. A growing body of research shows that we may want to pay more attention to circadian rhythm and our chronotype. Finding out if we’re more of a lion or wolf might enable us to help predict our risk of potential health problems, according to a recent study from the Scandinavian Journal of Medicine and Science in Sports. 

The study
The study, which looked at the physical activity levels of more than 5,000 participants, found that wolves had 60 to 90 minutes lower physical activity per day than lions. More research needs to be conducted, but it seems that certain body clock patterns and health conditions run together. There are a number of potential factors that come into play, one of which is cortisol. Cortisol, a hormone we associate with stress, has a powerful influence on sleep and waking in the human body. Cortisol gets you ready to fight, freeze or take flight. It can can also affect your mood, influence metabolism and digestions and aid your immune system when you’re ill or injured. So, how does cortisol relate to sleep and chronotypes? The production of cortisol in your body also follows a circadian rhythm, dropping to its lowest point around midnight and peaking about an hour after you wake up. 

Turn off the lights
If you’re having a hard time falling asleep, try these tips. Turn off the TV and dim the lights at least an hour before bedtime. Put away any screen that gives off a blue light as that glow signals your brain to stop producing melatonin. Take a bath, listen to some soft music and read a good book. Don’t fight your circadian rhythm, work with it instead! Remember, well over 90% of the repair work done on our bodies takes place at night. That’s what sleep is for.  Getting eight hours of sleep is a means of preparing us for tomorrow. And for most of us, if we don’t get our required amount of sleep, we still have to do tomorrow. Sleep on that!