I I used to think circadian rhythm was kind of a woo biohacker thing.
Like something only people with red light glasses talked about.
But the more I’ve looked into it, and the more I’ve seen this show up with clients, the more I realize how much this impacts how we feel, how we perform, and how our bodies respond.
And I think people focused on building muscle and losing body fat just brush over it.
Your body runs on a 24-hour cycle. Even without light, most of your internal processes still follow that rhythm. But light has a huge influence on how strong and aligned that rhythm is. And in today’s environment, that’s where things get thrown off.
We’re inside all day.
We’re under artificial light.
We’re on screens at night.
Over time, that adds up.
Circadian rythym dysgreulation is one of the common stressors on the body that adds to someones total stress load.
What Actually Runs on a Circadian Rhythm?
This isn’t just about sleep.
Testosterone runs on a circadian rhythm. It peaks at certain times and drops at others.
Cortisol and melatonin also follow a rhythm, and these two are inversely related. Cortisol should be higher in the morning. That helps you wake up, mobilize energy, and feel alert. As the day goes on, it should gradually come down.
Melatonin should rise at night to promote sleep and recovery.
When circadian rhythm is dysregulated, you’ll often see cortisol staying elevated, spiking at night, or failing to drop properly. That’s when people feel tired all day and wired at night.
Insulin sensitivity also follows a rhythm. It tends to be higher earlier in the day and lower at night. That matters for how we time food. Your thyroid follows a rhythm. Your immune system follows a rhythm. Gut health follows a rhythm. Even gym performance often peaks mid-day for many people.
When this is off, it’s not just that you’re tired. There are downstream effects everywhere.
You’ll often see patterns like:
- Lower total daily movement
- Reduced training output
- Blunted recovery
- Increased resting heart rate
- Lower HRV
- Poor appetite regulation
- More short-term, dopamine-driven decisions
And most people don’t connect those back to circadian rhythm.
They think it’s discipline. Or motivation. Or that something is wrong with their metabolism.
How the Modern Environment Wrecks This
In our current environment, it’s incredibly easy to drift into circadian dysregulation without realizing it.
Screens. Artificial light. Late meals. Caffeine too late. Stress right before bed. Inconsistent sleep timing.
If you stack those consistently, you end up in this flatline state. You don’t get deep, quality sleep. You wake up groggy. Energy feels blunted all day. Your body just feels confused.
And then the effects start stacking.
You feel more tired, so you don’t push training as hard.
Training quality drops.
Total daily movement drops.
Appetite regulation gets worse.
Short-term decisions start winning over long-term ones.
Now total daily energy expenditure drops. Now body fat creeps up. Increased body fat can worsen insulin resistance. You feel worse. Motivation drops further.
It becomes a feedback loop.
If resting heart rate trends up, HRV trends down, digestion feels off, recovery slows, or you feel like you’re working hard but not seeing changes, circadian rhythm is one of the first places I look with clients. Think of it as the foundation.
How This Impacts Body Composition
When circadian rhythm is off, things just become less efficient.
You’re more tired, which means less drive to train hard. Even if you show up, you might not push the same intensity. Over time, that matters for muscle growth.
You’re more likely to make short-term, dopamine-driven decisions. Food choices that feel good now but don’t align with your long-term goals.
Appetite regulation often becomes more dysregulated. Recovery slows. You’re more likely to get sick. You may feel like you’re “doing everything right” but not getting the response you expect.
It’s not one bad night of sleep.
It’s the consistent small misalignments that add up.
The Three Patterns of Circadian Dysregulation
There are three common patterns I tend to see.
The first is the night owl pattern. This is someone who struggles to fall asleep early, even if they try. If left to their natural rhythm, they may fall asleep between midnight and 4 a.m. and wake up late morning. They feel alert and productive at night but groggy in the morning.
The second is the early sleeper pattern. Less common, but it happens. Someone falls asleep very early and wakes up very early. If they want to shift that later, the approach is slightly different.
The third, and probably most common, is low amplitude. The signal just isn’t strong. Energy feels flat. Sleep isn’t deep. There’s no clear peak in the morning or drop at night.
You often see low amplitude with high stress, poor metabolic health, higher body fat, social jet lag, inconsistent sleep timing, aging, and chronic inflammation. As we age, circadian amplitude naturally decreases. Stress lowers it. Jet lag lowers it. Chronic poor habits lower it.
Biggest Circadian Rythm Mistakes
There are a few consistent leaks that show up over and over.
The first is not getting outside, especially in the morning. Morning light is one of the strongest signals you can give your brain. It doesn’t need to be sunny. Even cloudy daylight is significantly brighter than indoor lighting. Getting outside early matters. If someone truly can’t, bright light therapy can help, but natural light is ideal.
Caffeine timing is another big one. Some people are slow metabolizers. Birth control can extend caffeine half-life. Genetics matter. Cutting caffeine off between noon and 2 p.m. is a good rule of thumb for most people. And that includes tea, energy drinks, diet soda, chocolate. It all counts.
Light at night is a major issue. We don’t get enough bright light during the day, then we get too much at night. Overhead lights, screens, phones in bed. That flattens the signal. Turning off overhead lights, using lamps, reducing screen brightness, using night mode, and keeping your phone out of bed can make a big difference.
Irregular sleep and wake times also matter. You don’t have to be perfect. But if you’re sleeping 10 to 6 during the week and 2 a.m. to noon on weekends, that’s social jet lag. One weekend isn’t the issue. Consistency is.
Large meals late at night can also interfere. Digestion slows at night and insulin sensitivity is lower. In general, more food earlier and lighter meals later tends to work better. There are exceptions, like very lean individuals deep in a diet who may benefit from some carbs close to bed. But for most people, shifting calories earlier helps.
Alcohol and THC can help you fall asleep, but they hurt sleep quality. Keeping them as far from bedtime as possible matters.
High stress with no downshift routine is another common leak. Working right up until bed. Watching triggering content. Scrolling. If you don’t create space to downshift, your system stays elevated, and deep sleep suffers.
Movement and exercise help strengthen circadian rhythm. But very intense training right before bed can push your rhythm later.
Again, one time isn’t the issue.
Consistency is.
How to Fix Each Pattern
Now, the fix isn’t the same for everyone.
You have to match the intervention to the pattern.
1. The Night Owl (Delayed Phase)
If you naturally drift later and feel alert at night, your goal is to shift your rhythm earlier and strengthen the morning signal.
The biggest levers here:
- Bright light as early as possible after waking
- Reduce light aggressively at night
- Cut caffeine earlier than you think
- Move larger meals earlier in the day
- Avoid intense training late at night
Light is the biggest driver here. Morning light pulls the rhythm earlier. Night light pushes it later.
If this person keeps training hard at 9:30 p.m. and scrolling in bed, they’re reinforcing the delay.
2. The Early Sleeper (Advanced Phase)
This is less common, but you’ll see it.
Someone gets tired at 7 or 8 p.m. and wakes up at 3 or 4 a.m.
If they want to push that later, you almost reverse the strategy:
- Expose yourself to brighter light later in the day
- Slightly delay bedtime gradually
- Potentially train a bit later (not right before bed, but later than usual)
- Avoid very early morning light exposure
You’re trying to nudge the clock back.
This usually takes gradual adjustment, not one big shift.
3. The Low Amplitude Pattern
This is the most common. The signal just isn’t strong.
Energy feels flat.
Sleep isn’t deep.
There’s no strong morning alertness spike or clear evening wind down.
This is less about shifting timing and more about strengthening the amplitude.
That means:
- Consistent wake time
- Morning outdoor light daily
- Daily movement
- Earlier caffeine cutoff
- More calories earlier in the day
- Downshift routine at night
- Reduce late night stimulation and light exposure.
If metabolic health is poor, body fat is higher, stress is high, or inflammation is elevated, those need to be addressed too.
Circadian rhythm and metabolic health are synergistic.
Improving one helps the other.
When You Dial This In
When circadian rhythm is aligned, everything just runs with less friction.
Energy is more stable.
Mood is calmer.
Appetite is easier to manage.
Training feels better.
Recovery improves.
Fat loss feels easier.
I always say client A who feels good versus client B who is technically doing things right but feels flat and tired. The person who feels good almost always sees better long-term results.
And when I bring this up, the common response is, “I already do that.”
But most people have atleast one or two leaks.
This isn’t about perfection. It’s about tightening up the biggest issues so your body can actually respond to the work you’re putting in.
If you’re training hard and eating pretty well but still feel stuck, this is one of the first places I’d look.
Because if your circadian rhythm is off, you’re just making everything harder than it needs to be.
If this is something you need help with this is exactly the kind of thing we work on inside the Performance Recomp Method, my 1:1 coaching program. If you want to learn more click HERE.
