If you’ve ever suffered from insomnia, of any kind—think difficulty waking up or feeling rested, sleeplessness in the middle of the night, or not feeling tired until much later than you’d like to go to sleep—you likely understand the feelings that accompany poor sleep (loss of control and frustration sound familiar?) Furthermore, as sleeplessness tends to compound on itself, it can drive people to anxiety, obsession, and hopelessness. However, what if I told you that you have more control over this process than you think? When I recently learned about zeitgeber rhythms I was shocked that 1. I’d never heard of this sleep science, and 2. It’s not better known to the general public.
I learned that we have the power to harness our body’s functions—a lot more than we realize! This idea of discovering control over one’s body is deeply fascinating to me, especially in the context of the one thing we’re all seeking—a good night’s sleep. The idea that our brains are malleable, able to shapeshift and change with minor adjustments from our end is mindblowing to me! Okay… so if you’re not excited yet, you may not be as big of a brain nerd as me, but I promise this information is worth a read, if only for a more complex understanding of our brains and how our movement through the world affects our rest.
So, follow along below while I talk about zeitgeber rhythms and how you can reset your body’s internal clock using cues you control in your environments such as light, temperature, and mealtime. Yes, really!
Why do I care about a Zeitgeber Signal?
The word zeitgeber is German for the timekeeper. In the study of sleep science and neurobiology, zeitgeber signals refer to external factors that influence our body’s circadian rhythm and biological clock. It’s a fascinating web of environmental, social, planetary, and biological factors that signal and timekeep our body’s inner clock! To understand zeitgebers, it is helpful to have a basic understanding of the circadian rhythm. I really like the way The Sleep Foundation explains circadian rhythm.
“Circadian rhythms are 24-hour cycles that are part of the body’s internal clock, running in the background to carry out essential functions and processes. One of the most important and well-known circadian rhythms is the sleep-wake cycle. Different systems of the body follow circadian rhythms that are synchronized with a master clock in the brain. This master clock is directly influenced by environmental cues, [these are zeitgebers!] especially light, which is why circadian rhythms are tied to the cycle of day and night.”
The Sleep Foundation
Both the circadian rhythm and zeitgebers are important because when our circadian rhythm is in sync, we respond to the zeitgeber cues as they normally occur throughout the day, and all is well. But when our circadian rhythm is influenced improperly (think blue light or working the night shift), we sleep poorly, our schedule is “off” or we may have insomnia. There are a handful of different environmental cues or Zeitgebers that influence our circadian rhythm—it’s more than just light! By understanding them we can be sure to cue our bodies correctly and sync up with nature to harness our sleep and energy most efficiently.
We live in a world that is so far removed from how nature originally created our bodies, so it’s shockingly easy to throw off our internal clock without even realizing what’s happening, or how seemingly “normal” things we do may contribute to a sleep problem. Below, I dig into zeitgeber signals and what you can do to optimize them, hence stabilizing your internal clock.
Zeitgeber 1: Light
The most powerful zeitgebers are sunlight and darkness, and how they shift throughout the day. Light as a zeitgeber cue is very well researched in how it affects our circadian rhythm. Our bodies are carefully attuned to produce and suppress the hormones serotonin, melatonin, and cortisol according to the amount of light we are take in through our eyes. Interestingly there are special retinal cones and cells within our eyes, (that have nothing to do with sight, so they still exist in those that are blind! Whaaaa!?) that register this change in light from day to night.
Essentially, in the morning, when your eyes see sunlight your body kicks into gear for the day, producing cortisol, starting your daily clock, and giving you energy and wakefulness for the day. As the sun begins to set, and darkness settles in, the signal that suppresses melatonin (the sleepy hormone), begins to fade and your natural melatonin levels begin to rise, this causes you to feel sleepy. You might really be noticing this as we have moved into daylight savings time and it’s getting dark sooner.
Have you ever woken up in the middle of the night, turned on a light to go to the bathroom, and then had a hard time going back to sleep? Your body likely got the incorrect signal it was time to wake up and began to produce cortisol, the hormone that supplies energy to our muscles and brain, and helps us feel alert! This is a perfect example of how modern living and technology make it easy to give false zeitgebers and throw off our internal circadian rhythm. Now, let’s talk about how to support this natural process, stop interrupting it, and optimize your health!
How to employ this signal to your advantage
I’ve said it before and I’ll say it again—let nature be your guide. Following the natural rhythms of light and dark throughout a 24 hour period will best support your circadian rhythm, biological clock, and sleep patterns! Even if you can’t follow them exactly, try to simulate them within your home and with the light sources you have available.
- In the morning, to optimize energy throughout the day, throw open those curtains and stare into the sky towards the sun (not directly at it) for two to three minutes. It sounds straight out of a scene from a movie but its real! If you have a home with natural light, open all your curtains and let light in baby. This will actually set you up for a better sleep that night. Live in the PNW or somewhere with dreary weather? Going outside is still worthwhile, as you will get a good amount of “lux hours” or necessary sunshine in your eyes, even in indirect light. Research has proven that spending time in the sunlight first thing helps you wake up, feel energetic and boosts healthy levels of energy hormones like coritsol throihgout the day.
- Can’t squeeze in some sun? Use a light box. It’s not uncommon to be super busy in the morning, but if you’re suffering from insomnia or having a hard time getting your sleep cycle regulated (perhaps you work night shift or travel internationally often), investing in a light box could help you kick the rough Z’s. While not as helpful or strong as some sunshine time au natural, a light box produces similar effects to getting morning sun. This brand is a good one, Carex Day-Light Classic, or any option that supplies 10,000 lux or more will do the trick! Pst… This can also be helpful for people who suffer from seasonal affective disorder or live in dark parts of the world. If you’re worried about jet lag you can even travel with a box like this to help you adjust at your destination. I’ve heard fascinating interviews with sleep scientists who light box every morning believing its key to a longer life and more comfortable living.
- Try stepping outside and getting light throughout the day! An exposure in the morning, at lunch, and in the late afternoon is proven to help you sleep better through that night. The more days you’re able to get this in, the more your internal rhythms will begin to sync and naturally flow allowing for good sleep. If you cant get outside for lunch due to weather or time constraints, try eating near a window in your office or home.
- Avoid blue light and artificial light in the evening. There are about a million buzzy articles on the internet about this now, including a lot of blue light filtering glasses on the market to help combat artificial light influence throughout the day. While the idea is great, the jury is still out in regards to research on the actual benefits for your circadian rhythm. The best sleep hygeine you can employ is to try avoid blue light in the evenings as much as possible. Consider making it a rule that when the sun goes down, you begin to dim the lights in your home and use tablets, kindles, cell phones, and TVs less. This is a hard one but your sleep and levels of restfulness will thank you. Not sure about it? Try it for a week. The more we align our natural rhythms with what nature shows us the more our bodies will thank us in the long run.
Zeitgeber 2: Temperature
Sleep biology research shows that when the temperature drops at night, better sleep is ahead. This is because our bodies are programmed through our internal clocks to slightly decrease in temperature in the evenings—this change actually coincides with our natural melatonin (sleepy hormone) release. Follow your body’s cues and adjust your thermostat to support this natural cycle. On the flip side, keeping the temperature steady in your home through the day and night (72 degrees for life anyone?) could lead you to get poorer sleep. The optimal temperature for sleep is 65 degrees F.
How to employ this signal to your advantage
Depending on where you live you can achieve this nighttime drop in temperature in a few different ways:
- Turn down the thermostat or turn off the heat in the winter months when its time for bed.
- Try a hot shower before bedtime. When your body temperature is nice and steamy from the shower, you get out of the shower wet, your body between evaporative cooling and thermoregulation will begin to balance your temperature causing a drop, and signaling sleepy times ahead.
- Sleep with socks on! When your feet are warm, your body will try to regulate by cooling the rest of your body.
- Turn on a fan when you sleep and/or rethink your bedding for cooler sleep. Layering on a thick winter down comforter in the summer may not be supportive of big healthy Z’s.
- Run perpetually hot? Invest in a bed cooling system. My friends who have these rave about them. These are mattress pads that send cool air or water through them to cool your core temp. Here’s an option on Amazon. They can be pricey but if you’re a hot sleeper, it may be worth the investment.
Zeitgebers 3: Meals
When we think of sleep and rejuvenation, we often think of how we feel through the lens of emotions, mental state, alertness, and sleepiness, etc. However, it’s not only our brains that need rest, our entire body, including all of our internal organs, are impacted by our circadian rhythm, and need time to rest overnight. When it comes to our internal organs (and most specifically our digestive organs) their clock starts in the morning the moment we take our first bite of breakfast. After this initial cue, they work hard all day intaking and digesting calories to feed the rest of our body with energy.
From the time we take our last bite of food, our organs begin to wind down to rest—they too need a break from constantly being “on.” This allows them to function at their best through the next day and allows us to sleep better at night because our whole body is truly resting. When we eat late at night or eat for longer than 12 hours through the day, our digestive organs and larger system have no choice but to keep working, processing all the food and calories they now have to “make use of.” Additionally, newer research suggests that improper eating habits may affect insulin resistance, weight gain, and general metabolic health.
How to employ this signal to your advantage
- When it comes to food and zeitgeber cues the key is to stop cueing your body early enough in the evening that your organs have time to rest overnight. It is also helpful to eat on some kind of schedule to give your body regular and reliable cues about when to expect energy, so it can use it most efficiently. Be gentle on yourself though, life is crazy, so remember this is a shoot for the moon, land in the stars idea—just do your best!
- From the time you wake up and eat your first bite of breakfast, remember your internal digestive alarm clock just went off and your organs are beginning to work! Try to get your meals in for the day within 12 hours or less from your first bite of breakfast. If that’s not possible, do your best, the key is to eat for the same time, or less, than the time your organs are resting.
- An outstanding side effect of employing this zeitgeber cue is that many people shed pounds without changing their diet when they simply give their body time to be efficient. It actually goes hand in hand with intermittent fasting. Check out this article to read about the connections.
Takeaways for better sleep:
To wrap it all up, don’t forget if you’re having a hard time sleeping, or just want to dig into living as healthfully as possible, you have more control over your internal clock than you think! Employ these simple changes every day for a while and see how you feel. Do you notice that you sleep better? Do you feel more rested in the morning? It can be mindblowing to really tune in to your body, employ evidence-based changes, and watch yourself flourish day by day. Think about looking to nature as your guide, slowing down a little, and employing mindfulness into each part of your day—I promise you won’t be disappointed with the results.