Several months ago, I (Jen) wore a CGM—continuous glucose monitor—and it was super eye-opening.
It showed me something encouraging: when I ate the right foods, my blood sugar was actually pretty stable. But it also revealed that I still had some things to work on.
One of the most surprising things the CGM showed me was a huge blood sugar spike every night around midnight. What? After not eating for six hours? What on earth was going on?
It was incredibly frustrating to see a big nighttime spike that seemed completely unrelated to anything I’d eaten that day.
So, I started to dig.
What I learned was that a blood sugar spike in the middle of the night like that is often tied to cortisol. Instead of getting a healthy rise in cortisol in the morning—to help me wake up and feel alert—I was getting it at night – at midnight.
Are you kidding me? No wonder I hadn’t been able to sleep well for… years.
As frustrating as that realization was, it was also deeply empowering. Because once I understood the cause, I could start looking for a real solution. This wasn’t random. My cortisol rhythm was simply flipped.
But that raised an important question: How did my cortisol cycle get off in the first place?
Here’s what I learned.
Cortisol follows a light-driven rhythm. When we wake in darkness, go straight to screens, skip morning light, stay up late under artificial lighting, or rely on caffeine instead of natural circadian cues, the brain loses its sense of timing.
Cortisol then either spikes too late, stays elevated all day, or drops when we actually need energy—leaving us wired at night and exhausted in the morning.
It’s not a cortisol problem. It’s a timing problem.
Hmm… yep. That sounds like me.
So, what could I actually do about it?
Let’s look at what’s happening behind the scenes—and why this one habit can ripple through your sleep, mood, metabolism, and mental clarity.
Your Eyes Are Doing More Than You Think
Your eyes aren’t just for seeing what’s in front of you.
They’re also how your body tells time.
Inside your eyes are special light-sensing cells whose main job isn’t vision at all. Their job is to let your brain know whether it’s morning, daytime, or night.
When natural morning light hits your eyes, those cells send a simple message to your brain:
“It’s morning.”
That message goes straight to your body’s main timekeeper—the part of your brain that sets the daily rhythm for everything else.
Think of it like the conductor of an orchestra. Once the conductor raises the baton, every section knows when to come in. Without that signal, things get out of sync.
The Kind of Cortisol You Actually Want
One of the first things morning light helps regulate is cortisol.
Cortisol gets a bad reputation, but it’s not the enemy. In a healthy rhythm, cortisol is what helps you wake up, focus, and feel motivated.
Morning light triggers a natural rise in cortisol that:
- Helps you feel alert
- Gently raises energy and blood sugar
- Supports motivation and mental clarity
- Helps you wake up without relying on caffeine
This isn’t “stress cortisol.”
It’s timing cortisol.
When it rises in the morning like it’s supposed to, your body tends to feel energized during the day and calmer at night.
When it rises at the wrong time… everything feels harder.
How Morning Light Affects Your Sleep Tonight
Here’s something most people don’t realize:
Your sleep tonight is shaped by the light you got this morning.
Morning light tells your brain, “It’s daytime—turn melatonin off.”
But it also quietly starts a countdown.
About 12–14 hours later, your brain knows it’s time to turn melatonin back on.
When morning light is missing, delayed, or weak:
- Melatonin can show up too late
- Falling asleep becomes harder
- Sleep becomes lighter and less restorative
This is why screens at night and darkness in the morning both disrupt sleep.
Your body needs contrast—bright days and dark nights—to feel safe and settled.
Light, Mood, and the Brain
Morning light also boosts serotonin in the brain.
Serotonin isn’t just about feeling good—it’s also what your body uses later to make melatonin.
More serotonin in the morning often means:
- Better mood
- Better focus
- Better sleep later
This is why regular morning light exposure has been linked to improved mood, reduced anxiety, and greater emotional resilience.
Your brain expects light as a daily signal that the world is predictable and safe.
How to make this work
To get the benefits:
- Go outside within 60 minutes of sunrise (windows don’t work the same way – the glass blocks the right rays from getting to your eyes)
- Face the general direction of the rising sun in the sky (no staring at the sun)
- Aim for 5–10 minutes on bright mornings
- 10–30 minutes on cloudy days
Sunglasses can block the signal—save them for later in the day when possible.
It’s really as simple as that!
I know what you’re thinking – it’s the middle of winter!
Yep. I did just suggest that you go sit outside for 10 minutes every morning… in the middle of winter.
I almost didn’t write this blog post thinking it would be much more practical to wait until summer to encourage you to get outside. But this habit has made such a difference in my life, I couldn’t wait.
My answer… just bundle up! Most mornings, if it’s not below freezing, you’ll find me sitting outside in fuzzy socks, warm slippers, insulated leggings, a warm coat, wrapped up in a blanket with a beanie on my head.
I look absolutely ridiculous.
But it’s 7am. No one’s looking at me.
When it’s below freezing, like most days now, it’s a little too cold. A friend of ours helped me find a solution.
Stay inside but open the window and look out. Opening the window removes the glass barrier that blocks the right rays of light from hitting your eyes.
You’re still going to get hit with cold air, but at least your body is inside where it’s warm. You only need 10 minutes.
How this has made a difference in my life
I am NOT a morning person.
So, when our friend, Suzanne Bates, first taught me this solution I didn’t see any way I could make it happen. By the time I was rolling out of bed, it was WAY past sunrise.
But I knew I needed to make a change. My insomnia was getting worse and worse a long with all of the other symptoms of not sleeping well.
So, I just had to suck it up and make it happen. I started this fall when the sun was coming up around 7am. I knew I had an hour, so I set my alarm for 7:00 hoping to be out of bed by 7:30.
It was brutal. But I did it and sat outside getting morning sun. I was able to do it every day for a week before my schedule was disrupted but even in that first week, I had a huge shift!
By 9pm I was tired. By 10pm, I couldn’t keep my eyes open and had to go to bed.
What?
After years of taking melatonin, rubbing on lavender essential oil and anything else I could think of and begging my body to let me sleep; only to go to bed at midnight or 1am and lay in bed not sleeping for several more hours after that-
Being able to sleep was awesome! I wasn’t perfect but was able to get morning sunlight at least 4-5 times a week for the next month.
Then life happened and my morning schedule got disrupted and I wasn’t able to get morning light for about 2 weeks. And my insomnia came back.
I realized how important this part of my morning routine is and have committed to not skipping weeks every again. It’s not about perfection, it’s about consistency.
This one simple habit has completely changed my life. Give it a try today
