The Power of Your Internal Clock: Circadian Rhythm and Natural Light

By Dr. Jennifer Paulson, DNP, FNP, CNP

Our bodies are incredible, intricate machines, and one of their most fundamental operating systems is the circadian rhythm – our internal 24-hour clock. This natural cycle regulates countless physiological processes, from sleep-wake patterns to hormone release and metabolism. Increasingly, research highlights the profound impact of aligning our circadian rhythm with natural light exposure for optimal health and well-being.

Years ago when many of my colleagues were slathering up with sunscreen and claiming the sun was harmful, I was screaming a big NO. In fact, I could identify in my very inflammation prone body that the sun was actually anti-inflammatory and I linked my seasonal winter depression to lack of natural light. This started my journey to research the benefits of sunlight, natural light and how it aligns with our biological 24-hour clock. I believe this knowledge was one of the most influential healing modalities in my journey and could be yours too.

Metabolism and Energy Production:

When our circadian rhythm is disrupted, our metabolic health can suffer. Studies have shown that irregular sleep patterns and exposure to artificial light at night can impair glucose metabolism and increase insulin resistance, contributing to weight gain and an elevated risk of type 2 diabetes. Conversely, consistent exposure to natural light, particularly in the morning, helps to synchronize our internal clock, optimizing the body’s ability to process food and produce energy efficiently. This alignment supports a healthy metabolism, allowing our cells to function at their peak.

Mood and Cognitive Function:

Natural light plays a crucial role in regulating neurotransmitters like serotonin, often called the “feel-good hormone.” Exposure to bright light, especially sunlight, boosts serotonin production, which is essential for maintaining a positive mood, reducing symptoms of depression and anxiety, and improving overall cognitive function. Conversely, insufficient natural light exposure can disrupt this balance, leading to seasonal affective disorder (SAD) and general feelings of lethargy.

Hormone Balance:

The circadian rhythm is a master regulator of our endocrine system. Key hormones, such as melatonin (which promotes sleep) and cortisol (our “stress hormone”), operate on a distinct 24-hour cycle. Natural light exposure helps to properly signal these hormonal releases. Morning light suppresses melatonin, promoting wakefulness, while the absence of light in the evening signals melatonin production, preparing the body for sleep. Disruptions to this cycle, often caused by late-night artificial light, can lead to imbalances in these crucial hormones, impacting sleep quality, stress response, and overall physiological equilibrium.

By prioritizing natural light exposure – especially in the morning – and maintaining a consistent sleep-wake schedule, we can support our body’s natural rhythms and unlock a wide range of health benefits, from improved metabolism and sustained energy to balanced mood and optimal hormone function. Embrace the power of your internal clock for a healthier, more vibrant you.

Daily Considerations & Resources

Download the app MyCircadian to learn more about lux (brightness of light in your environment), daybreak/sunrise/sunset times for your location.
Get 3-5 minutes of daybreak light in your eyes in the morning.
Get natural sunrise and daylight exposure to your eyes. Walk outside, sit by a window, measure your lux. You will be shocked the difference this makes!
Change your eating habits to align with eating your meals earlier in the day and fasting in the evening. Fasting times are individualized to gender, genetics, but in general healthy individuals should be resting their GI from digestion for 12 hours overnight.
Use a dawn simulator alarm clock like this one. It this helps me wake up when I must use an alarm clock
Avoid computer screens at least 2 hours before bedtime. OR wear blue blocker glasses ONLY before bed. Blue light exposures suppresses melatonin production for 2 hours from exposure. Melatonin is another blog post, but it’s a super antioxidant and prevents cancers, protects your immune system. Help your pineal gland make melatonin. Turn off the screen, read a book, and use a red light reading light like this one.
Do not block all sunlight and natural light by wearing sun glasses. There is a fine balance here, but the light must enter your eyes. You do not need to stare at the sun, but allow natural light to enter your eyes.
Allow sunlight to hit your skin so you can make vitamin D. The app mentioned above will tell you the best times for UV availability from the sun. Use common sense. Do not burn or damage your skin. Let the app guide you, this is the most natural way to make vitamin D. We have enough evidence to show that the sun is not our enemy when it comes to cancer, it’s our friend when used properly.
Moon bathing is a real thing. Walk outdoors or sit under the moon and stars. This also helps to align your 24-hour clock.