Shadow and Light

The Science Behind Your Circadian Mood Swings

Most people feel better on sunny days. That’s not a preference, it’s biology.

Light affects your mood, focus, and creativity.

These shifts follow a rhythm called the circadian cycle, which runs on a 24-hour clock, guided mostly by light.

Your brain has a small region called the suprachiasmatic nucleus. It’s located near the optic nerves and acts like a timekeeper.

When light hits your eyes, it sends signals to this part of the brain. That signal tells your body what time it is and helps regulate hormones like melatonin and cortisol.

Melatonin helps you sleep. Cortisol helps you wake up and stay alert.

When light exposure is strong in the morning, cortisol levels rise and melatonin drops. You feel awake, focused, and ready to move. If you miss that morning light by staying indoors or waking up late, your body stays sluggish longer than it should.

This is why people feel groggy on cloudy mornings or during winter. It’s the lack of light triggering your internal clock.

Light exposure affects serotonin, a chemical linked to happiness and emotional balance. Bright light, especially in the morning, helps boost serotonin.

That’s why people who get outside early feel more upbeat. Artificial lighting leads to lower serotonin levels, causing irritability or sadness.

Creativity follows this rhythm. Many report feeling most creative during early morning or late evening. These times line up with lower distractions and softer light. Morning light helps with clear thinking and planning. Evening light, especially during sunset, triggers reflection.

This is where sunrise and sunset meditations come in.

Meditate during sunrise to reset your internal clock. You’re exposed to natural light, which regulates hormones and improves alertness. It’s a quiet time, easier to focus. 10 minutes facing the light can help.

Sunset meditation works differently. As light fades, your body prepares for rest. Melatonin rises. Meditate during this time to slow down, process the day, and ease into sleep. It’s a time for gratitude, journaling, or quiet breathing.

A writer who wakes up at 6 a.m. and sits near a window while planning their day feels focused and productive. Their cortisol levels rise, and their brain fires. By 9 a.m., they’re deep into work.

Someone who works late into the night under harsh artificial light struggles with sleep. Their melatonin cycle is disrupted. They feel tired the next day. If they switch to dimmer light in the evening and add a sunset meditation, their mood stabilizes.

Take a walk outside in the morning, open blinds early, or step out during lunch to reset your rhythm. Avoid bright screens before bed to wind down.

Pair light exposure with reflection. Use sunrise to plan. Use sunset for review. These habits need to be consistent.

Your body responds to light. Work with that rhythm or fight against it. The more you align with natural light, the better your mood, focus, and creativity.