In today’s article I want to touch on what’s the best humidity level for sleeping?

Short Answer: Between 30-50% in  your bedroom.

I always sleep better when the air is less humid. It’s something I’ve noticed since I was in my early 20s. I had a chance to travel around the world for an entire year when I was 26 years old and traveled to some really hot countries like Australia, South Africa and Brazil to name a few.

Not only were they hot but the air was muggy and you always felt like you were sweating all the time. Your skin always felt “moist”. Girls love the humidity because it gave them that “glowy skin” they’re always looking for.

But first…

Let’s understand what humidity really is…

• Definition: Humidity refers to the amount of water vapor present in the air.
• Measurement: It is typically measured in grams per cubic meter (g/m³) of air.
• Types:
  • Absolute Humidity: The actual amount of water vapor in the air, regardless of temperature.
  • Specific Humidity: The ratio of the mass of water vapor to the total mass of the air parcel, including the water vapor.
• Implications: Absolute humidity is a straightforward measure of water vapor content, but it doesn’t consider the temperature of the air.

I don’t mind the moist air but I don’t love sleeping in it. You can invest in a little humidity checker for your bedroom just so you can check the levels throughout the day and night.

As you probably know I’m a guy and most guys tend to be hot sleepers. I sweat in bed quite a bit.  Since I’m already a warm sleeper any added temperature or humidity levels just add fuel to the fire.

We live in Southern California where the humidity typically averages between 55% and 65% for the year.

For me I like around 30% humidity. When the air is more dry it carries an electrical charge and it’s just easier to regulate temperature that way. When there’s a lot of water particles in the air it becomes heavier and more dense which make is more difficult and requires more energy to cool down.

I’ve also noticed that even if I have an air conditioner on in the summer, I could still be sweating underneath my sheets because the air is thicker and more dense.

More Humidity = Less Colds & Flu?

The upside higher humidity levels is that people tend to not spread the cold or flu as much. There’s less contagion. My theory is that particles that become airborne when people cough or sneeze cannot travel as far (because the humid air is more dense, think about shooting bullet in a pool) and any viral particles that do become airborne attach to water molecules and fall to the ground.

That’s just my theory on humidity levels and spreading a cold or flu.

Humidity Levels – Find The Sweet Spot

The trick about humidity levels is that there’s a sweet spot.

If the air is too dry then it could cause breathing issues during the night and it could cause skin issues like itchiness and scratching. Dry air also seems to be better at spreading colds and flus too. The upside of dry air is that it’s easier to regulate the temperature. It’s easier to make colder to sleep in.

The benefits of warmer more humid air is that it could actually help with breathing issues during sleep and skin issues.

The best humidity level for sleeping is 30 to 50% but you have to find what works for you and your current sleep schedule.

If you sleep with a partner you’ll have to figure out what he or she likes as well since this is a shared space.

How I Regulate Humidity Levels

Summertime Humidity Levels

During the summer months when there’s a heat wave I’ll use an air conditioner in the bedroom along with a high quality dehumidifier. The benefits of this is that it makes the air conditioner work much less hard because it’s not trying to cool air that is dense, warm and full of water particles and water vapor. I also combat this with the Chilipad bed cooling system which uses much less energy than an air conditioner but it’s much more expensive also.

If you have the funds, personally I would invest in anything that helps you biohack your sleep so you can have more energy, and live longer.

Wintertime Humidity Levels

In the winter you have a couple things going for you. It’s much colder which creates a much more conducive sleep environment. For this reason you don’t really have to run an air conditioner so that will also save you some money.

What I like to do in the Winter is to use a high quality cold humidifier, in case the humidity levels are too low, which does happen from time to time here in Southern California.

Managing Light From Bedroom Devices

Many of these devices have green, yellow or blue “indicator” lights on them. We know that even a few photons of light can impact melatonin secretion.

There’s an interesting study which I’ll paste a few lines from below:

Twenty-six healthy individuals participated in a 9-day inpatient protocol that included assessment of dim light melatonin onset time before and after exposure to a single 15-second or 2-minute pulse of bright light (9,500 lux; 4,100 K fluorescent) or control background dim light. Both 15-second and 2-minute exposures induced phase delay shifts of –34.8 ± 47.2 minutes and –45.4 ± 28.4 minutes, respectively, that were significantly (P = 0.04) greater than the control condition. These findings may have real-world implications for circadian disruption induced by exposure to brief light stimuli at night.

How do these indicator lights affect sleep if our eyes our closed? Many people sleep with their eyes partially open, this is a condition called nocturnal lagophthalmos. Through what’s known as light refraction or photon scattering, the light from these devices can enter your eye (if they’re open during sleep) and prevent the release of melatonin.

You don’t want that.

This why I cover all the indicator lights from any devices with special blue blocking tape that blocks the specific frequency which alter circadian rhythms. I also sleep with a sleep mask on “just to be safe”.  I also highly recommend blocking any light coming in from your windows during sleep.

Light at night is not recommended for insomnia or any sleep condition. In fact it has been associated with a higher risk of all cause mortality.

Exposure to brighter light at night, recorded with personal light sensors in >88,000 participants, was associated with higher risk of mortality across a subsequent 6-year period. Computational modeling indicated that disrupted circadian rhythms may explain this higher mortality risk. Minimizing exposure to light at night and keeping regular light-dark patterns that enhance circadian rhythms may promote cardiometabolic health and longevity.

and then there’s this paper.

“Dim light at night (LAN)-induced melatonin suppression disrupts this circadian-regulated host/cancer balance among several important cancer preventative signaling mechanisms, leading to hyperglycemia and hyperinsulinemia in the host and runaway aerobic glycolysis, lipid signaling and proliferative activity in the tumor.”

When it comes to sleep and light, I don’t mess around.

Conclusion

As you continue to play around with different sleep environments you’ll notice that some things you do will help you sleep better while other things you do don’t seem to make much difference. You can track what actually works using an Oura Ring but honestly you don’t need that. You can know how well you slept by how you feel the next morning.

I mention all the time to stack the odds in your favor and keep refining and tweaking not just your daily habits but also items in your room to create the ultimate sleep environment for yourself. The air we breathe while we sleep is one of those components that you can change.

I encourage you to keep trying new things and see what kind of effects it has.

Questions

• Do you notice a difference if the air is dry vs more humid?
• Does your partner like the same or opposite?
• What humidity levels do you feel best sleeping in?

Comment below.