Circadian Rhythm

How to Align Your Circadian Rhythm for the Best Sleep Schedule

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Your ability to get good quality sleep hinges on whether your circadian system is properly aligned with your desired day/night cycle.

If your brain and body think it’s still time to be awake when you want to go to bed, guess what? You ain’t goin’ to bed. *sassy finger snapping*

What is Your Circadian Rhythm?

Human beings require daily exposure to bright light to help attune our internal clocks to the rhythm of the Earth.

circadian rhythm graph showing the daily rhythms of cortisol, melatonin, growth hormone, potassium, and temperature
As you can see, there are many things in the human body that function on a 24-hour cycle.

We’re going to go over some strategies you can implement to make sure the right signals are being presented at the right time.

I’m not going to get into the nerdy nitty-gritty circadian biology stuff here, there’s plenty of that out there already, this guide will focus on the practical application side of things.

Defining Your Sleep Schedule

Before we get into the daily strategies that will help align your circadian rhythm and get you sleeping like a freshly suckled baby, we need to go over some ground rules.

  • Schedule the time: As an adult, you should be getting around 7-9 hours of sleep every 24 hours. Make sure you are giving yourself time for this. You should be able to wake up naturally to a light alarm after 8 hours or so of sleep without the need of an audible alarm.
  • Step it back if you need to: If the thought of not using an alarm clock perturbs you, slowly step back your bedtime until you can comfortably risk sleeping in a bit in the morning. If you need to step it back by an hour, don’t try it all at once, do 10 minutes every 2-3 days.
  • Keep the same bedtime: Go to bed at the same time every day! You need to stay consistent if you want to sleep well within a confined work-life schedule, there’s just no way around this. Social jet lag is fine and understandable if it’s not happening every weekend, and it isn’t negatively affecting your quality of life.
  • Pay attention to your drowsiness: Even if you think doing everything right, you may need more sleep. I you notice you’re consistently tired during the day (not just after lunch) you may just need to step that bedtime back, or have your dawn simulation turn on a little later. These things can take time to figure out.

How to Wake Up in the Morning

Circadian alignment begins first thing in the morning, so this is where we’ll start.

Use a Sunrise Alarm Clock

Waking up naturally and as peacefully as possible sure does sound nice, doesn’t it?

We should be waking up with the dawn, as the light slowly increases, our brains bring us out of sleep when they’re ready to.

  • In this small trial, eight participants were separated into a control or dawn simulation group. The dawn simulation group experienced better-perceived sleep quality, significantly higher alertness, improved cognitive performance, and better times in a self-paced cycling exercise. [R]
  • In this study, subjective sleepiness after waking was significantly lower in the DsL group. Better waking was attributed to a quicker decrease in skin temperature, signifying better distal to proximal skin temperature regulation. While the authors state that no significant cortisol secretions were found, the DsL group clearly has higher waking cortisol up to 30 minutes. [R]
  • The use of the artificial dawn resulted in a significant reduction of sleep inertia complaints. The dim light melatonin onset (DLMO) was the same in all groups. [R]
  • In this study, participants were sleep restricted for two nights in a row and put into one of three light experiments. Mood and well-being were significantly enhanced after exposure to morning dawn simulation light compared with the dim light and blue light groups. Salivary cortisol was also higher post-wake-up in the dawn simulation group. [R]
  • Seventeen young men were woken up two hours before their normal wake time. In the group that had dawn simulation light (DSL) 30 minutes before being awoken, there was a significantly calmer heart rate gradient upon waking. [R]
  • In this study, the participants who were subjected to changing temperatures similar to the patterns seen in nature, i.e. a gradual decrease as bedtime approached, and a gradual increase as the wake-time approached, experienced better-waking sensation and higher urine melatonin on waking. [R]
  • Gradual changes in light and temperature both in the morning are associated with high melatonin levels in the morning and lower drowsiness upon waking. [R]

The Best Sunrise Alarm Clocks

As you can see, simulating natural dawn, both with gradual light changes and temperature changes, can make a difference in our circadian biology.

With that being said here are the best sunrise alarm clocks:

71jOT4egLTL. AC SL1500

Philips SmartSleep Wake-Up Light

Philips makes the best and brightest wake-up light on the market. It’s a bit expensive, but buy once cry once. This light starts off at a very dim red/orange color and advances into a bright white/yellow light. The cheaper options below suffer in color, brightness, and overall user experience.

61sh804kObL. AC SL1500

Generic Sunrise Alarm Clock

This is a great option for those of you who want a sunrise alarm clock but absolutely cannot swing for the price of the Philips.

How to Use a Sunrise Alarm Clock

You’ll want your sunrise alarm clock to reach full brightness at your desired wake-up time. Setting it for a half hour is enough, although you can experiment with longer.

Don’t use the audible alarm functions! Being jolted out of your peaceful slumber at a specific time is going to defeat the purpose of this whole thing. Duh.

The Best Products to Simulate Dawn Temperature Rise

51e7wknd2PL. AC SL1000

Aireplus 1500W Oil Filled Radiator Electric Heater

Set your thermostat to slowly increase the temperature over a 2-hour period by at least 5 degrees. If you don’t have this capability, you can also schedule a room heater to do the same thing with an outlet timer, just make sure it’s in a safe place, and you have a smoke detector in the room! Safety first. A programmable radiant oil heater is also a good option.

51rOyGRfFBL. AC SL1000

BedJet 3 Smart Climate Bed Fan

The Bedjet is another option for slowly warming up your microclimate. This is my preferred method as it preserves the natural feel of your mattress, unlike pad-based cooling gadgets.

Get Bright Light Exposure First Thing After Waking Up

After you wake up, you’ll want to get into bright light right away. This is of utmost importance if you have issues falling asleep.

Bright light after waking will phase advance all aspects of your circadian rhythm. Meaning you’ll produce more cortisol after waking, and you’ll produce melatonin sooner in the evening.

How Much Bright Light Should You Get?

You want about 15-30 minutes of bright light exposure after waking. This is especially important for those of you with any issues falling asleep or waking up. If the sun is out, go outside and go for a walk. If it’s still dark outside because you work a 9-5 in the winter. Spend some time in the morning in front of or near a very bright source of light.

Build Your Own SAD Lamp

Traditional light therapy lamps use very bright blue phosphor pump LEDs, which will wake you up but are very unlike natural light. You can make your own light therapy lamp by using GE Sun-Filled BR30-style LEDs. This will give off around 10,000 lux at 1 foot, putting it firmly in the light therapy camp, but with a much healthier, fuller light spectrum.

DIY light therapy lamp using five ge sun filled br30 bulbs

DIY Light Therapy Lamp

This is a DIY light therapy lamp using five GE Sun-Filled BR30 LED bulbs. It should cost you around $70 to build this.

Here’s what you’ll need:

Buy a Luminette Light Therapy Device

If you drive a lot in the dark winter mornings, or just want to utilize light therapy in a more convenient on-the-go manner, Luminette is the best option around. They offer glasses and a new driving-compatible light therapy device!

61KNeja3oQL. AC SL1500

Luminette Light Therapy Devices

These can be a great addition to any biohackers toolset.

Tip: Sign up for Luminettes newsletter for 10% off!

Staying Awake During the Day

Getting morning exposure to bright light is important, but the rest of your day cannot be spent in darkness either!

The Importance of Circadian Stimulation

Bright light is needed to set the human circadian “clock”. Since every single process in the body relies on this input, so it’s extremely important that you’re sufficiently exposed to light that can accomplish that.

The Lighting and Research Center (LRC) has developed a metric for this, called Circadian Stimulus (CS). You can read more about that here if you’d like.

A graph made by the LRC that's derived from nocturnal melatonin suppression studies shows that with increasing lux there is more circadian stimulus.
This graph made by the LRC is derived from nocturnal melatonin suppression studies, as they are the best available proxy for circadian stimulation in published literature. As you can see, both warm and daylight lux can stimulate the circadian system, with the biggest determinant being brightness. (Source)

Now, it’s not very difficult to achieve the LRC minimum recommended CS of 0.3, and in my opinion, we should all be striving for a CS of 0.7+ during the day. The lux required to achieve this still pales in comparison to the brightness of even the darkest overcast day.

This is a bit harder to achieve and almost guarantees you’ll need to add a bit more light to wherever you spend a lot of time during the day.

Using the calculator above, make sure your office lighting is hitting 100 fc. My personal office is actually over this, and I could comfortably go higher. This ensures a high CS without needing to do many calculations.

Get More Bright Sunlight Exposure

Daytime is all about bright sunlight. The more bright light exposure you have, the better your sleep will be. From waking up, to falling asleep, to staying asleep, bright light is the answer!

Spend as Much Time Outside as You Can

Regardless of how much light you bring into your indoor space, it will never match the raw power of the sun. Get outside as early and as often as you can, the more you do, the better your sleep will be.

Get Your Office as Close to Windows as Possible

At work or at home, try to get your office space as close to a window as you can, south facing windows are best. If this isn’t possible, then the east is second best, as a bright light in the morning is far more important than in the evening. Obviously, avoid glare and any other uncomfortable issues that can arise.

Replicate Sunlight Where it’s Needed

If you’re trapped indoors all day long, whether that’s at home or in your work cubicle, you need to make sure you’re getting bright enough light in your eyes to thoroughly activate the circadian response. My guide on How to Replicate Full Spectrum Sunlight Indoors is definitely worth a read if you think you might benefit from this.

Stop Needlessly Wearing Sunglasses

There are modern environments where wearing sunglasses if efficacious, such as very shiny roads, snow, or water. But if you’re the type to just slap on a pair of shades because the sun is out and you’re outside, gasp. Stop it.

Wear Tan Through Clothing

Get a tan-through shirt to use as an undershirt for work, when you go outside to eat lunch you can take your work shirt off without drawing much attention to yourself. While typical shirts let in 1% UVB, tan-through lets in 50%. The white is pretty see-through, so you may want to get a darker color.

DIY light therapy lamp using five ge sun filled br30 bulbs

Tan Through Shirts

Cooltan offers tan-through shirts you can wear under your work clothes.

Measure Your Vitamin D Intake

UVB exposure is necessary to synthesize vitamin D3 sulfate, a water-soluble form of vitamin D3 that can travel freely throughout the body.

DIY light therapy lamp using five ge sun filled br30 bulbs

D Minder App

You can track your vitamin D exposure with the D Minder app! It’s interesting to see and gives you an idea of what you’re likely getting.

Winding Down in the Evening

Finally, as our day comes to an end, it’s important that we respect this time as it would be in nature, and the message it has for us to slow down.

Limit Late Night Exercise

  • Intense physical activity within one hour of sleep may negatively affect sleep onset latency, total sleep time, and sleep efficiency. [R] [R]
  • Other than that, in general, exercise in the evening doesn’t appear to be associated with negative sleep outcomes or circadian phase delays. [R] [R] [R]

Keep Calories Low

It’s generally recommended to limit larger meals to earlier in the evening for various reasons.

  1. Glucose tolerance is limited following melatonin secretion. [R] [R]
  2. Gastric emptying is slower. [R]
  3. Resting metabolic rate slows. [R]

So ideally, the evening is not the best time to consume a large number of calories.

However! There are studies and literature on evening meals and snacks not having much of a negative impact on healthy individuals.

  • When shifting the evening meal from 5 hours before bed to 1 hour before bed in 20 healthy adults, no disruption in sleep quality was found. [R]
  • Nighttime snack consumption does not appear to be detrimental, and may even be useful in some cases. [R]

That being said, it’s probably best to keep large meals 2-3 hours away from bedtime, but if you’re hungry before bed, you may find sleep comes easier and deeper if you indulge in a little snack, I know it does for me.

Lower the Temperature

This one is pretty simple, the temperature of your environment should gradually decrease as your bedtime approaches.

Just set your thermostat to drop by 5 degrees two hours or so before you’ll be nodding off.

  • Gradual changes in light and temperature both in the evening are associated with high melatonin levels in the morning and lower drowsiness upon waking. [R]

Warm Dim Evening Lighting is Important

As a general rule, it’s important that we keep our lighting dim and warm before bed.

  • In this study using a 4000K light source and around 50 participants, lux levels of just 10 were enough to suppress melatonin by 50% in some. While others did not reach 50% suppression until light levels reached 400 lux. [R]
  • In a study comparing red light exposure with bright white light, the red light still phase shifted a few people, with two participants shifting just as much as the bright light group. [R]
  • Circadian responses to 555 nm green light are too strong to account for just a melanopsin response, meaning that cone receptors contribute to circadian entrainment. [R]

Now, you’ll often see red and orange/amber lights recommended here. I personally find the spectrum from lights like this to feel very unnatural and unpleasant, and quite frankly, it’s unnecessary. They’re also typically much too bright and every single low-wattage LED light bulb I’ve found has insanely high levels of flicker, which I’m not very comfortable with.

I’ve personally tested several of these light bulbs (you can find the test data here), and I’ve come to the conclusion that a C7 incandescent night light is where the parties at, the slumber party that is.

Now before you ask… yes, incandescent lights give off some short wavelength light, but what’s important is this amount is so small that it has no meaningful chance of disrupting your melatonin secretion at night.

The Best Low Blue Light Bulbs

So here’s all the light you’ll need to get all cozy before bed:

DIY light therapy lamp using five ge sun filled br30 bulbs

The Bedtime Bulb

This is a great custom phosphor LED bulb perfect for use late at night. It comes in both a regular and candela size.

You’ll want to utilize dimmers for these as the night draws on as they are a bit bright for the latter hours of the night.

  • 4-6 watts
  • 300-450 lumens

DIY light therapy lamp using five ge sun filled br30 bulbs

Incandescent Night Lights

These bulbs give off a really dim, warm (2200K) full-spectrum light that will have you snoozing in no time.

The 7w 50 lm bulbs are great for living rooms, kitchens, and bedrooms, while you might prefer the 4w 15 lm bulbs for bathrooms and smaller bedrooms.

You’ll likely need an adapter to use these in standard light sockets as well.

DIY light therapy lamp using five ge sun filled br30 bulbs

Glocusent USB Rechargeable Book Light

If the lights above aren’t bright enough to read by, you’ll need something else.

I like this light because it remembers the dim warm setting, and you don’t have to cycle through the brighter options once it’s set.

Blocking Blue Light From Electronics

If you have any trouble sleeping at all, I recommend complete abstinence from electronics two hours before bed.

However, if you’re going to use them anyway, it should be done responsibly.

Below are some strategies for mitigating blue light from electronic devices:

Turn on Night Mode on Your Devices

Whatever your device, be it a Windows PC, MacBook, iPhone, or Android, it should be set to night mode two hours before you plan to go to bed. Below are some examples of what this does to the light output on your devices.

Use a Web Page Darkening App

You can drastically cut down on blue light and the overall brightness emitted from your computer by installing Dark Reader on your web browser. This website has its own night mode, as you will have hopefully seen.

DIY light therapy lamp using five ge sun filled br30 bulbs

Dark Reader

I prefer setting this up so that it turns on when my device shifts to night mode. It helps to remind me that it’s getting close to bedtime and to start wrapping up my work.

Download the IRIS App

IRIS is an application that allows for better dimming control on Windows machines, which I consider essential. If you own a webcam, you can let IRIS use that for monitor auto-dimming, even if your computer doesn’t support such a thing.

DIY light therapy lamp using five ge sun filled br30 bulbs

Iris App

A great application for Windows machines, however some of the features didn’t work as well on my Macbook Air so I’ll recommend the program below for MacOS users.

  • Get 10% off with the link below

Download the Lunar App

If you own a MacBook, you owe it to yourself to get Lunar on it. Lunar gives you far more control over dimming, including the ability to auto-dim external monitors in sync with your laptop.

DIY light therapy lamp using five ge sun filled br30 bulbs

Lunar App

I have my Lunar app set to Sensor mode so that my external monitor dims with my MacBook as I dim my office lights.

The Best Blue Blocker Glasses

It’s nice to have a pair of blue blockers for travel, late nights, or even at home if you have rather unhealthy roommates. The mainstream blue blockers are all really overpriced, so I recommend staying away from basically all of them.

I’ll link to some more affordable options, then some of the better-looking more stylish pairs available.

DIY light therapy lamp using five ge sun filled br30 bulbs

Infield Terminator Blue Blocker Glasses

This is definitely one of the better budget blue blocker options I could find. Don’t look half bad either!

DIY light therapy lamp using five ge sun filled br30 bulbs

Low Blue Lights Fitover Blue Blocker Glasses

These are the best fit-over version I can find, for those of you who need to wear glasses.

DIY light therapy lamp using five ge sun filled br30 bulbs

Bon Charge Blue Blocker Glasses

If you’re looking for something a bit more stylish and don’t mind spending a bit more, the offerings over at Bon Charge are a decent pick!

Block Bright LED Lights

There are a few other ways we can block out pesky blue and green wavelength lights.

DIY light therapy lamp using five ge sun filled br30 bulbs

Amber Screen Filters

If you like to read at night with an electronic device, you might find it useful to attach an amber screen filter to it to mitigate the more energetic blue light. And remember to use it as dimly lit as comfortably possible!

DIY light therapy lamp using five ge sun filled br30 bulbs

Light Blocking LED Covers

Blue LED indicator lights should be made illegal, who’s with me?! Bring pure darkness back into your life by extinguishing all the annoyingly bright lights in it.

The Best Ways to Darken Your Room

As you go to sleep, it’s important to keep your bedroom dark at night.

The natural night is extremely dark, and you don’t want any man-made light causing your body any confusion about what time of day it is.

Make sure your room is blackout dark at night, you shouldn’t be able to see your hands move in front of your face. This is necessary above and beyond eye masks because even your skin has photoreceptors that can detect light.

Use a combination of blackout shades and blackout curtains if you have to, the darker the better. When setting up curtains, use a wraparound rod. You can also use a draft stopper to block light from under the door.

DIY light therapy lamp using five ge sun filled br30 bulbs

Blackout Shades

A good pair of blackout shades over your bedroom window can make a world of diffierence at night. Select blinds have a ton of options to choose from if you can’t find what you need locally.

DIY light therapy lamp using five ge sun filled br30 bulbs

Blackout Curtains

Depending on where you live, blackout curtains might do the job, or maybe they can assist in light blocking with the shades.

Where I live I have street lights to content with, so I need both to effectively eliminate outdoor light.

DIY light therapy lamp using five ge sun filled br30 bulbs

Wraparound Curtain Rod

You’re going to need a curtain rod for those curtains!

DIY light therapy lamp using five ge sun filled br30 bulbs

Door Draft Stopper Snake

Block that pesky roommate light from interrupting your beauty sleep with a draft stopper snake!

DIY light therapy lamp using five ge sun filled br30 bulbs

Attachable Door Draft Stopper

Block that pesky roommate light from interrupting your beauty sleep with a draft stopper snake!

The Best Sleep Mask

Everybody needs a good sleep mask. If you can’t get your room dark enough, either your partner is reading with the light on, or you’re traveling, a sleep mask is the solution.

DIY light therapy lamp using five ge sun filled br30 bulbs

Manta Sleep Masks

Manta makes the best sleep masks on the market by far. Check out their collection to find which one would suit you best.

TLDR: Putting it Into Action

This section is for those of you who either don’t have time to connect all the dots above, or just want a quick list of things that can be done to optimize your biology.

  1. Wake up around the same time every day with a dawn-simulating sunrise alarm clock.
  2. Expose yourself to bright light within 15 minutes of waking up for at least 10 minutes.
  3. Get all-day bright light exposure, and create your own light setups if necessary.
  4. In the evening, keep your exercise and meals light.
  5. Keep evening lighting very dim and warm, two hours before bed.
  6. Blackout your bedroom to keep artificial light from disrupting your circadian rhythm and sleep.

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