Circadian Rhythm: Nervous System Health Starts with the Sun

Hi dear one,

There’s a quiet wisdom in your body that most of us overlook. It’s your circadian rhythm, your body’s internal clock that governs nearly every process in your system. It plays a huge role in how regulated or dysregulated your nervous system is.

I first discovered the benefits of taking care of my circadian rhythm shortly after I listened to one of the first Huberman Lab episodes about sleep and wakefulness, probably back in 2022. I learned very quickly from my own experience that there is no “method” more powerful to help you regulate, heal, be present, more positive, more energised throughout the day than being in line with your internal rhythm.

Yes, you can do ice baths, you can do breathwork, you can eat right, take walks or try any other biohacking trick there is, but if your circadian rhythm is severely disrupted, the benefits just aren’t going to be as good.

The best part of all this is that I didn’t have to completely change my life, just introduced a few simple rules that I stayed consistent with. Even better, all the tools are completely free.

Let’s talk about what it is, why it’s so important, and what you can do to improve it.

What is a Circadian Rhythm?

Circadian rhythm is your body’s internal 24-hour clock that governs sleep, alertness, hormone release, digestion, body temperature, and more. Supporting it helps regulate your nervous system by reinforcing predictable cycles of rest and activation, which your brain and body rely on for safety and stability.

Because circadian rhythm coordinates so many processes and is built in nearly every cell in our body, when it gets disrupted your nervous system can become dysregulated. This imbalance can affect your mood, energy, immune function or even overall health.

Common Disruptions and Simple Ways to Regulate It

Morning Sunlight

Morning sunlight is one of the most powerful tools for regulating your circadian rhythm. Getting outside within 30-60 minutes of waking helps anchor your internal clock for the day. It boosts cortisol at the right time (for alertness), and promotes melatonin release at the right time (for sleep).

This works only if you do it when the sun is still low in the sky, a time known as the low solar angle - because the light at this time contains the wavelengths your brain relies on to signal wakefulness and set the timer for melatonin release later.

You don’t need to stare directly at the sun, just being outside with your eyes open is enough (never look directly at the sun if that’s uncomfortable or painful). It’s important not to wear glasses or try to get this light through windows because glass filters out the key signals. You have to get outside to get this benefit or at least stand next to an open window.

On bright, clear mornings, just 2–10 minutes is often enough. On cloudy or overcast days, aim for 15–30 minutes. It still works — it just takes a little longer.

Consistent wake/sleep times

Consistent wake and sleep times are foundational for nervous system health. Your brain and body operate on a circadian rhythm that thrives on regularity. When you wake up and go to bed around the same time every day (yes, even on weekends), you’re reinforcing a strong internal rhythm. This consistency helps regulate hormone cycles (like cortisol and melatonin), stabilizes mood, supports immune function, and increases your capacity to handle stress.

One of the most powerful anchors of the circadian clock is the timing of your waking. Getting up at a consistent time each morning, ideally shortly after sunrise, is more impactful than the exact hour you go to bed. This regular rhythm trains the brain to anticipate both wakefulness and rest, which in turn makes falling asleep easier and staying asleep more reliable.

When I decided to try this for the first time, I needed an alarm clock for the first three nights. I set it to 5am. It was summertime, which probably explains why I felt so brave to start this early. To my surprise after just 3 days of doing the “morning sunlight” ritual I started to wake up just minutes before the alarm clock was supposed to go off. After a week, I decided I didn’t need the alarm clock anymore because my internal clock worked just as precisely. But I didn’t just find the ability to wake up earlier, I also started genuinely enjoying early mornings.
Something I didn’t think was possible before, as I used to dread the days I had to wake up early.

Meanwhile, if we have irregular sleep-wake patterns, waking up one day at 9am, another at 11am, going to bed a few nights per week at 2am, can lead to so-called “social jet lag,” where your internal clock becomes misaligned with your actual schedule. Over time, this can affect mood, focus, and even metabolic health. The nervous system, in other words, doesn’t just want sleep but wants rhythm and consistency.

Dim the evening light

Bright lights at night, especially overhead lighting and blue light, can delay the natural rise of melatonin, the hormone that prepares your body for sleep. This disruption signals your nervous system to stay alert, making it harder to wind down.

Scrolling your phone or using screens late in the evening adds to the disruption, as the blue light they emit mimics daylight. For me, this was one of the hardest things to conquer as I was addicted to scrolling reels every night before bed. The irony was that I was telling myself I need to do this because I’m having trouble falling asleep otherwise. If I didn’t use my phone in bed, I would toss and turn for 30 minutes or more trying to fall asleep. I didn’t realise that using blue light late at night was what had been causing the issue in the first place. So, I made a pact with myself to simply leave the phone outside of the bedroom. I don’t need it next to me when I sleep. Everything will wait for the next morning and I won’t pick it up until after I’ve done my morning sunlight viewing.

One of the most natural ways to cue your system that it’s time to slow down is to view the sunset. Just as morning sunlight helps your waking rhythm, watching the light shift in the evening supports the body’s transition into rest. After sunset, keep your environment dim and warm. Soft lamps, candles, salt lights or better yet, a red light can help signal safety and relaxation to your nervous system, allowing melatonin to rise and sleep to come more easily.

Avoid Caffeine too late

Caffeine works by blocking adenosine, a chemical in the brain that builds up throughout the day and signals when it’s time to rest. When caffeine blocks that signal, we feel more alert, but this can backfire when used too late in the day.

For most people, having caffeine within 8 to 10 hours of bedtime can interfere with the body’s ability to wind down. And it’s not just about whether you can fall asleep or not. Often I hear people say “oh but I can fall asleep just fine after coffee late in the day, even right after”. Sure, I believe you. But there is a high chance that your sleep will not be deep or restorative enough. You may wake up feeling groggy or unrefreshed, without realizing caffeine was part of the reason.

With that in mind, I have a simple rule in my house: no caffeine after 12pm, but before that, enjoy as much as you like.
We love our coffee and matcha and I’ve found that even within this short window, it works really well for me. I actually don’t feel the need for caffeine later in the day at all.

Evening rituals

For those who want to be really extra, you can add the step of creating an evening ritual. This can include breathwork, journaling, a warm drink (I sometimes make myself a really good quality, sugar-free cacao), some stretching or yoga, maybe just sunset viewing is enough for you. It really should be your ritual, decide on what makes you happy.

Other habits that influence your circadian rhythm

Other things that influence your circadian rhythm include the timing of food intake, timing of exercise and temperature shifts.

Eating at consistent times during the day, especially avoiding heavy meals late at night, helps set your internal clock. Movement also acts as a time cue, so if your goal is to start waking up earlier in the morning, try scheduling your exercise earlier in the day and avoid late-evening exercises.

Exposure to cold like a morning cold plunge or a cold shower can increase alertness and be very beneficial in waking you up in the morning. However, again, if your goal is to wake up with the sun the next morning it’s best to avoid it late in the day. The opposite goes for sauna or heat exposure, it can help your body relax and prepare for rest. So it is recommended to do sauna in the evening.

No matter where I am in the world, I always make it a point to wake up early enough to catch the low solar angle sunlight in the morning, and to make time, even if just for a few minutes, to watch the sunset in the evening.

Ultimately, the key to nervous system health and deep restoration lies in reconnecting with the natural rhythms that have guided humans since the beginning. Our modern lifestyle often pulls us away from those rhythms. But I truly believe that going back to basics, honouring the sun’s rise and set, and making a consistent sleep-wake schedule is the simplest, most powerful path to balance. With going back to what our bodies always relied on, we not only support better sleep and energy, but also become more resilient, emotionally stable and happier.

With light and love,
Ema