The connection between using an air conditioner or fan during sleep and muscle pain is not a figment of your imagination or an old wives’ tale. It’s a real phenomenon with clear physiological explanations. To solve the problem, it’s important to understand what exactly happens to our body when we’re exposed to cold air currents for extended periods.
Local cold and direct airflow: Muscles tend to contract when they’re cold. If the air conditioner or fan is directed at a specific area of the body (like the neck or back), it creates a kind of "local freezing," an involuntary muscle contraction that can lead to stiffness, pain, and even waking up in the middle of the night.
Sudden temperature changes: When moving from a hot to a cold environment suddenly—like entering a bedroom with an air conditioner set to a very low temperature—the muscles experience a kind of "temperature shock." This sudden change causes muscle contraction, which can persist even after the body adjusts to the new temperature, leading to morning pain. This effect is particularly strong when the air conditioner is set to a very low temperature or when a person sleeps very close to a strong airflow.
Unnatural sleep posture: To avoid strong or overly cold airflow, your body might shift to distorted or contracted sleep postures during the night. These unnatural postures can put significant strain on the muscles and spine. Additionally, the combination of an incorrect sleep posture with exposure to cold creates a "perfect recipe" for muscle pain.
Using an air conditioner correctly can ensure a cool, comfortable sleep environment and a morning free of muscle pain. The basic principles are simple but very important.
Use a timer: Many of us run the air conditioner on regular cooling mode all night. A better approach is to use the "sleep" mode available on most modern air conditioners or set a timer to turn off the unit after 2–3 hours. During the first few hours of sleep, the body needs cooling to relax and fall asleep, but toward the early morning hours, the temperature drops, and the need for artificial cooling decreases.
Drink water and check the air conditioner’s cleanliness: Air conditioners dry out the air, which can lead to mild dehydration that affects muscle flexibility, especially in those who don’t drink enough water during the day. Additionally, dirty filters create dry, polluted air, which can worsen headaches and general discomfort and reduce the air conditioner’s efficiency, prompting you to lower the temperature further.
Don’t direct the fan straight at your body: Just like with an air conditioner, an angled direction or toward the ceiling is preferable. If that’s not possible, place the fan at least one meter from the bed or use the oscillation feature to avoid continuous exposure of a specific body area to the breeze. With ceiling fans, such adjustments aren’t possible, so it’s doubly important to follow the other tips.
Choose a medium to low speed: A fan on high speed not only creates disruptive noise but also an overly strong airflow that can cause muscle contraction. Most modern fans offer at least three speed settings—use the lowest speed that still provides a pleasant cooling sensation.
Prefer a fan with a timer: Like with an air conditioner, it’s not always necessary for the fan to run all night. Sometimes a few hours of airflow are enough to create comfortable sleep conditions, and the body will continue to sleep comfortably after the fan turns off.
Drink water and check the fan’s cleanliness: Using a fan mainly dries out the outer parts of the body and can cause dryness in the skin, lips, and even throat. So, even if you don’t use an air conditioner at all, it’s still advisable to stay hydrated throughout the day and before bed. Additionally, it’s a good idea to clean the fan blades and cage occasionally to avoid being "attacked" every night by dirty air filled with dust particles.
If you wake up at night with pain or stiffness, it’s a sign that something in your sleep conditions is unbalanced. Try moving the fan, changing the temperature, or adding a light blanket layer.
