Why Do Fans Help You Sleep

Silver fan

I’ve personally been using a fan for the past 10 years of my life, and to anyone who hasn’t used one yet, I highly recommend it. I’ve gotten so used to having one on while I sleep that I wouldn’t know how to get to sleep without one. I’m addicted to the white noise and cool breeze it provides when I sleep. But this got me wondering why does sleeping with a fan on actually help you sleep. Well, today I’m going to answer that question from what I’ve learned.

As mentioned earlier fans provide us with white noise, a cool breeze on our face, and just a general sense of calm.

The white noise helps to drown out other noises that would otherwise disturb our sleep. And the air that the fan blows on your face helps to regulate your body’s temperature.

If you’ve ever stuck your foot out from under the covers and have enjoyed the feeling, then you’ve experienced some form of temperature regulation.

To go further white noise allows us to concentrate on a constant noise. Have you ever walked into the room with a strong smell only to realize a few minutes later that you can no longer smell it? This is called olfactory fatigue, and it is defined as “the normal inability to distinguish a particular smell after prolonged exposure.” Our brains grow accustomed to the smell; an evolutionary advantage that humans developed to help distinguish between new smells. Being able to sense new stimuli helped our ancestors to detect new danger, such as an approaching predator, and thus you can see why it was passed on.

Just like olfactory fatigue, your brain grows accustomed to noise, and since the white noise produced by the fan drowns out the other noise while sleeping, the result is a quiet room (from the viewpoint of your brain) perfect for sleeping.

In terms of the temperature regulation component that a fan provides, sometimes I find it most comfortable to sleep with a fan blowing on my face in a cold-ish room, with 2-3 blankets on me. Did I just guess the way you like sleeping? Maybe, maybe not! Everyone is different. Some people have a lower internal temperature. A normal adult usually falls in the range of 97°F to 99°F, while a child’s temperature could be anywhere from 97.9°F to 100.4°F. And so how you likely sleep will greatly depend on your normal internal temperature. If you aren’t sick right now, go rummage through your medicine cabinet and find a thermometer. Take your temperature a few days in a row (around the same time). Mine runs a little low, at 98.1°F.

Also, a quick myth I want to bust is that we lose half of our heat from our heads. The heat we lose is actually fairly proportional to the surface area of skin. Which is why we only lose roughly 7% to 10% through our heads.

Is it Bad to Sleep With a Fan on?

So we’ve already covered why using a fan can help you sleep, but is it bad to sleep with a fan on? The answer is probably not. While there are some health concerns associated with the dust that a fan blows around the room in terms of allergies, the general consensus from the medical community is that a fan is not at all harmful. Just by taking some simple steps to minimize the dust found around your room, by just dusting regularly, you should be okay! My fan itself usually does get quite a bit of dust that gets stuck inside it and usually just taking a vacuum cleaner and cleaning out the fan blades will suffice. If you notice that the dust still won’t budge, consider taking apart the fan (carefully), vacuuming it, then using a wipe, wipe down the fan blades, put it back together and let it sit for at least 20 minutes to dry. I usually have to do this twice a year, so make a habit of keeping your fan clean if you want to avoid allergies.

If you use your fan in an especially cold room, pointing right at you, watch out for a stiff neck in the morning. The cold air directed at your head and neck area will cause the muscles in your neck to tense overnight, and so you might wake up with a sore neck if you crank the A/C too and use a fan at the same time.

The last thing to watch out for is the potential for a fan to dehydrate you. And we will talk about that next.

Does Sleeping with a Fan on Dehydrate You?

Does sleeping with a fan on dehydrate you? Yes, it very well could. It happens to me all the time so I thought it was important to add this section in. According to LiveScience, “anything that causes rapid air movement, including a fan, can evaporate moisture from your mouth and nasal passages, drying them out.”. So if you have your fan on high, right in front of your face the entire night then yes it could definitely happen, especially if your mouth is slightly open. What I do if I notice I have a dry throat a couple of nights in a row is I’ll move the fan back a few feet, or I will put in on a lower setting. Having a bottle of water right next to you in case you wake up during the night works too. And if you are adamant about having your fan blowing in your face all night consider buying a humidifier to help add some moisture to the dry bedroom air.

I personally recommend the Pallas Humidifier from Amazon. I have used it extensively in my dry room (with the fan on), and I never wake up with a sore throat. From experience, I’ve never realized how much having the correct amount of humidity in the room can affect how you feel waking up, especially if you are prone to waking up with a dry/sore throat!

Does Sleeping With a Fan on Make Your Throat Hurt?

So I covered this part in the last couple sections, but yes, sleeping with a fan on may make your throat hurt, especially if you’re sleeping with one on high, and close to your face. The air could evaporate the moisture in your mouth and throat causing some soreness. In addition, if you are already in a cold room with the A/C cranked up, or the window opens the cold air could cause vasoconstriction (decreasing size of blood vessels). The mucous membranes inside your nose and throat experience this normal automatic response which helps to reduce the amount of heat lost to the cold air. The decreased blood flow causes a decrease in the normal secretions our mouth and throat provide to keep everything from drying up, making your throat hurt as a result.

I wrote an entire article about why you get a sore throat from sleeping with a fan on, and some useful tips and tricks to prevent it from happening – you can check that out here!

Why Do I Get Sick Sleeping with a Fan On?

Sleeping with a fan on won’t directly cause you to get sick. It’s not that the circulating air is harmful to you. But it is possible for a fan to indirectly cause you to get sick. Since we’ve established that sleeping with a fan on or more prominently in a cold room will cause you to dehydrate and your throat to be sore, let’s go a step further and talk amount one of the properties of mucus in your mouth, nose, and throat.

According to MIT Scope, “The average person generates more than a liter of mucus a day, including snot, saliva, cervical mucus, as well as protective coatings for the digestive system, urinary tract, lungs, nose, and eyes”. Which is a crazy amount, they continue by saying that, ”
Mucus covers 400 square meters of surface area in an adult body, roughly the same area as a basketball court”, which in my opinion is an absolutely mind-blowing fact about the human body.

The role of mucus is actually more important than I had once thought. Here is yet another quote from MIT Scope that explains further explains the role of mucus.

Mucus performs a number of important functions to keep the body safe from infection. New microbes constantly attempt to invade the human body, many of the disease-causing pathogens. When fragile parts of the epithelium — the outer layer of skin and the linings protecting organs — crack, microbes have an easy access point. To prevent this, mucus keeps the epithelium well-lubricated. Mucus also coats the existing entry points into the body, such as the nose, mouth, and stomach, and catches pathogens that try to get in that way. The mucins form a powerful sticky mesh, like a glue trap that the invading microbes get stuck in, preventing them from moving any farther into the body. Then antibodies, immune cells, antimicrobial proteins, and bacteria-infecting viruses contained in mucus can kill the pathogens or isolate them to prevent them from building up.

MIT Scope

Since mucus is reduced in the throat and mouth, and since it performs such a vital role in our immune response, it’s easy to see how having a reduction in it would make a pathogens job easier at infecting us. So while sleeping with a fan can make you sick (indirectly) as long as you take the proper precautions, you’ll be fine. Prevent your nose, mouth, and throat from drying up by using a humidifier, moving the fan farther away, putting it on a lower setting, closing the window during a cold night, or not cranking the A/C up too high in the summer. Follow those things and you should be golden!

It might be the level of air quality in your bedroom getting you sick; if you are serious about not getting sick from sleeping with a fan on, or in general I highly recommend using an air purifier. I recently bought the LEVOIT Air Purifier from Amazon. You’ll enjoy the benefit of actually breathing in dust-free clean air, and not being worried about getting sick from pesky allergens and other irritants living in our bedrooms.

Can You Sleep With a Fan on All Night?

Yes. Definitely. I love sleeping with a fan on all night. I’ve been doing it for the past 10 years. I’ve had it turned on during the whole night throughout that entire time. I can’t imagine how much I’ve spent on electricity because of it, but I wouldn’t ever consider not using one!


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