What’s Your “Zeitgeber”?
Zeitgeber: noun
zeit-ge-ber (ˈtsīt-ˌgā-bər )
a rhythmically occurring natural phenomenon which acts as a cue in the regulation of the body's circadian rhythms.
I recently had a fascinating discussion with one of my morning clients, who has a series of great questions about light and health.
This started because she was having some sleep troubles, and I suggested that she go outside every morning around sunrise, no glasses or sunglasses, to get natural light in her eyes.
Now, you might be wondering what the sunrise has to do with sleeping, right? It’s all about our circadian rhythms - internal processes in our bodies that regulate our sleep and wake cycles, digestion, body temperature, hormone production and release, and much more.
Think of it like your body’s own internal, master clock.
Those circadian rhythms last about 24 hours, and they are set by two main “Zeitgebers” - the combination of two German words: zeit meaning “time” and geber meaning “giver.”
Light is the #1 zeitgeber for humans. Food is #2.
Let’s go back to my morning client . . . she began sitting outside on her patio, reading, for about 30 minutes around sunrise. And she does feel a difference. And you will too.
Here is a recap of our conversation, set in Q&A format for ease of reading.
Q: Why is it important to see the sunrise?
Light and darkness are fundamental to the health of all animals, including humans. Our bodies are wired to sense daytime and nighttime and to respond differently. For example, during the daytime, it’s good to be alert, energetic, and active. During nighttime, those things are not good, because we should be resting, relaxing, and sleeping. Our bodies completely change our hormones and other parts of our biology in the daytime versus the nighttime.
So when we get our “light” signals mixed up, by staying up too late with bright light and/or not getting enough bright light in the mornings and daytime, our bodies get mixed up. And over long periods of time, that results in fatigue, sickness, disease, and ultimately, early death.
Fun fact: melatonin, the “sleep hormone” is released at night, but did you know that it’s mostly produced in the morning? That’s another reason why early morning sun can help you sleep better later that day.
Q: How long should I be outside in the morning?
Initially, I suggest at least 30 minutes if possible. As you do this regularly for a few weeks, you can reduce your time if needed.
The habit and regularity of seeing the early morning sun is more important than doing it for a specific amount of time.
For example, with all my morning classes during the week, I can usually only stand outside for 2-3 minutes each hour, but I do it every single day without exception.
Q: Do I look directly at the sun? What about glasses or sunglasses?
No, don’t look straight at it. I’d suggest looking about 30 degrees off to the side of the sun.
If you wear sunglasses, glasses, or contact lenses, you are preventing the full spectrum of sunlight to enter your eyes. That’s a problem. The “master clock” of your entire body is the suprachiasmatic nucleus, which sits right above the optic chiasm in your brain, where your optic nerves cross. It receives light directly from the retina in the back of your eyes.
Related: if you are highly sensitive to sunlight or changes in light, you could be deficient in magnesium. Try 600-800 milligrams of magnesium glycinate or magnesium threonate for 1-2 months and you may see improvements.
Q: Does it matter that the light is coming through a bunch of big trees? Do I need to see it directly?
Not enough to worry about - the sun is bright enough that being anywhere outside in the early mornings is sufficient to tell your brain and body to “wake up.”
Q: What should I do if it’s cloudy or overcast in the morning?
You can still go outside and get all the benefits of early morning sun.
Q: When should I eat breakfast? Before I go outside, after, during?
Ideally, eat breakfast during or just after you are outside in the morning. The early morning sun will prep your digestive system for better assimilation of your breakfast. This works even better if you expose your stomach to the sun directly, no clothing.
I eat breakfast before sunrise most days because of my schedule at the gym. So I stand in front of my red light box, shining directly on my stomach, for 5-10 minutes while I’m prepping breakfast and making coffee. I do feel this helps my digestion throughout the day.
Q: What about at night? I’ve been wearing the red-tinted, blue-blocking glasses - what else should I do?
The eyes are the most important to protect at night, so blue-blockers are very important. The skin also detects and responds to light, so if you’re going to be up past sunset watching TV or on a computer, I would also wear clothing that covers most of your skin.
IN SUMMARY: Early morning sun, bright days, dark nights.
Go outside, no glasses and as little clothing as legally and morally permitted, each morning for at least a few minutes.
Do the same thing in the middle of the day if possible.
Do the same thing again at sunset if possible.
Avoid too much artificial light at night.