Fireplaces can make you sleepy by generating warmth that relaxes your muscles and from the white noise generated by the burning firewood. Fires are also usually lit at nighttime, after the last meal of the day has been consumed and darkness has fallen, which also both trigger your body to go to sleep.
It is also important to keep in mind that although fireplaces do help us relax and often make us sleepy, you should never actually go to sleep with your fire still burning. Risks from an unattended fire include poisoning from noxious fumes as well as house fires.
1. Fires Are Warm
You were probably able to guess this one, but one of the main reasons that fires can make you sleepy is because they also make you warm.
Warmth is commonly used to treat sore muscles after workouts. This does a few things for you, including dilating your blood vessels (which helps to flush out toxins like lactic acid), making your muscle fibers more elastic, and even stimulating your nerve endings to block pain.
The same things happen to your muscles when you’re in a warm room. In this case, a warm room heated by a fire. Your blood flow increases, your muscles relax, and you literally feel less pain. All of these can definitely guide you into a resting state, especially when coupled with other attributes of fire like the sound it makes.
2. Burning Firewood Is Natural White Noise
The sound of an open fireplace is a distinctive one, with the crackling of flames on the wood and the occasional snapping or popping. A lot of people know that they find the sound of an open fireplace soothing, but they don’t know exactly why.
Turns out that it’s for the same reasons that many people use white noise machines to help them sleep in noisy places: In sound engineering terms, actively burning firewood is a source of acoustic noise that effectively masks other background noises that might disturb you.
The soundscape of a fireplace is a combination of white noise and impulse noise. White noise is the combination of sound in every frequency that the human ear can detect (~20 to 20,000 hertz) played together at the same amplitude in a continuous flow. Think of the quiet crackle of the wood slowly dissolving under the flames. Impulse noise, in contrast, is an intermittent or instantaneous noise in those same frequencies. Think of the pop of escaping moisture or the sudden snap of a collapsing log.
Together, these acoustic features of a fireplace create a smooth “wall of sound” that covers up undesirable, sporadic sounds like traffic going past your house or the voices of your neighbors.
Combined with the warmth generated by the flames, this soundscape naturally encourages your body to relax. This wall of sound also helps the brain to rest by cutting off its auditory stimuli, allowing it to take a break from processing and interpreting the sounds around you.
3. Fires Are Lit At Night
The typical time that people light fire is at night, either for warmth or for light. Regardless of whether you are an early bird or a night owl, your body has a sleep-wake system that is largely triggered by natural light levels i.e., sunrise and sunset. You may have heard of this system, which is known as the circadian rhythm. It is your body’s master clock, and it decides when certain systems in your body and brain are turned or powered down.
The greater darkness after sunset is interpreted by your body as a signal to begin producing melatonin, which is a hormonal trigger for sleep. And if you’ve also recently eaten dinner, the release of hormones related to digestion can further trigger drowsiness.
And if you enjoy beer or wine with your dinner or after it, the alcohol in these beverages acts as an additional depressant to your system, slowing you down and increasing your feeling of sleepiness.
Do Gas Fires Make You Sleepy?
Gas fires can trigger sleepiness as well, though their effect is more muted than that of an open fireplace.
Unlike open fireplaces, gas fires provide the atmosphere of a fire without as much warmth. They are also missing the soundscape of snapping, crackling wood that combines impulse noise and white noise.
However, gas fireplaces are usually still located in comfortable locales like living rooms and bedrooms, where they can add to a relaxing ambiance and encourage sleep. And if you’re close enough to the glass pane of the fireplace, the radiant heat will still reach you and provide its benefits too.
However, there is a more sinister reason that your gas fireplace might be making you sleepy.
Are Fumes From Gas Fireplaces Harmful?
The biggest hazard of a gas fireplace is carbon monoxide poisoning, and it is important to properly maintain both your fireplace and your carbon monoxide alarms to prevent this.
Many gas fireplaces are ventless inserts, which means that they were installed into what was originally an open firebox and have no exhaust system that removes gas fumes from the house. These ventless systems are designed to completely burn all gases within the combustion box, and many of them do come with an oxygen depletion sensor (ODS) that acts as an automatic shutoff if levels of CO reach a certain threshold.
But you should still make sure that you also have a separate carbon monoxide detector in the same room and regularly check its batteries.
Remember that carbon monoxide is odorless and colorless, and its symptoms include dizziness, chest pain, weakness, disorientation, and headache, all of which might keep you from acting effectively to save yourself–that is if you’re even able to realize you’re having a problem.
Most fatal carbon monoxide poisoning cases occur when a person is sleeping or heavily inebriated, and thus, unable to recognize the fact that something bad is happening to them.
Is It Bad to Sleep With the Fireplace Still On?
So if fires make us sleepy by keeping us warm, wrapping us in a cocoon of soothing white noise and synchronizing with our circadian rhythm, then shouldn’t fires be safe and effective to use as a sleep aid? Not really. Although it is tempting to do so, in this case, the safety risks far outweigh the benefits.
Going to sleep while leaving your gas fireplace still on, or with wood burning, is generally not a good idea. Even when contained in the confines of a fireplace, fire is a powerfully destructive force and it does require monitoring from a conscious human being.
We just touched on how fumes and carbon monoxide poisoning can be an issue with gas fireplaces, but open fireplaces can also be a source of noxious fumes, especially if the wood you’re burning is wet, unseasoned, or a kind of pressure-treated wood like plywood.
Burning inappropriate kinds of firewood is never a good thing, but it becomes even worse when you do so while you are sleeping. When unconscious, you are unable to respond to symptoms like dizziness or confusion that might be your only clue that something is wrong.
Additionally, houses and the things that are in them are generally flammable. This makes leaving a fire unattended at night very dangerous; even with a metal screen or glass in front of the firebox, there is no way to one hundred percent guarantee that nothing will go wrong, and sparks or embers might still escape. Like candles, fires should only be lit when a conscious human being is nearby to intervene if an emergency situation arises.