Jay Summer is a health content writer and editor. She holds a B.S. in psychology and master's degrees in writing and public policy.
Taking a hot bath or shower at night may be the best way to unwind after a stressful day. In fact, a number of studies have shown that a hot bath or shower before bed can improve overall sleep quality, as a change in body temperature may bring on that sleepy feeling and help someone fall asleep more quickly.
For some people, bathing at the end of the day includes washing their hair, which may still be wet when they get into bed. It is a commonly held belief that sleeping with wet hair is a bad idea, increasing the risk of waking up with a cold or leading to a head of tangled and broken tresses.
Despite these widely held beliefs, there is not a lot of strong scientific evidence that sleeping with wet hair is going to cause problems for everyone. Rather, there are certain circumstances that may make a person want to consider whether it is okay to sleep with wet hair or to take the time to let it dry before bed.
We take a closer look at the potential risks of sleeping with wet hair and provide tips for taking care of your hair while you sleep.
As wet hair dries overnight, some water evaporates into the air and some becomes absorbed by pillows and other bedding. Sleeping on a warm damp surface can create an environment near the face and scalp that might cause problems. People who regularly go to sleep with wet hair may want to look out for any changes in the health of their skin or hair when deciding whether to continue with this kind of bedtime routine.
Although research studies have not thoroughly explored the potential side effects of sleeping with wet hair, some people still caution against this habit, believing that sleeping with dry hair can help prevent certain health problems.
Sleeping with wet hair does not always cause damage, but there are some circumstances that may increase the likelihood of waking up with tangled or broken strands.
Each strand of hair is made of a complex network of proteins and cells that determine the strand’s strength and elasticity, or how much it can stretch before returning to its original state. Wet hair that has not been chemically treated has the ability to be stretched by up to 30% of its original length without causing serious damage or breaking.
However, chemically treated hair is more fragile and prone to breakage. Each strand of hair is naturally protected by a layer of brittle scale-like cells called the cuticle. The cuticle contains certain types of fatty acids that make it hydrophobic, or less likely to absorb water when wet.
Some hair styling products strip fatty acids from the cuticle, allowing more water to be absorbed. This can cause a hair strand to swell and weaken its overall structure. Without proper care, chemically treated hair is more likely to become frizzy and tangled as it dries. The added friction from sleeping on a pillow with wet hair may also make things worse, pulling some strands of hair farther than their elasticity allows, leading to breakage.
There is no direct evidence that sleeping with wet hair will cause a person to develop acne. Nonetheless, some people caution against sleeping on a damp pillow, believing it to be an ideal environment for certain types of bacteria to thrive, potentially increasing the risk of skin problems like acne. However, the reality of how acne occurs and why sleeping with wet hair may pose a problem is a little more complex.
Acne can happen when pores become blocked by the body’s natural oils and dead skin cells. Most people experience acne at some point in their lives, usually during adolescence. In most cases, acne is due to family history or to changes in hormone levels which can increase the body’s natural oil production and influence how well the skin clears away oil and dead skin cells.
If bacteria becomes trapped in a clogged pore, it can trigger the immune system to react, causing an inflammation commonly referred to as a pimple. The types of bacteria that cause acne exist naturally on the surface of everyone’s skin and do not usually cause problems unless they become trapped in a pore.
The risk of developing acne is not related to poor hygiene or even the likelihood of coming into contact with bacteria in the environment, like on a pillowcase. Rather, a pillow that is damp or has collected residue from hair products could potentially make acne worse by creating an environment that is humid or oily, leading to clogged pores. For these reasons, some experts suggest it is better to sleep with clean and dry hair that is pulled away from the face.
For some people, sleeping with wet hair may lead to problems with their scalp. Both pillows and hair follicles can harbor certain types of fungi, a type of organism that can thrive in moist or damp environments.
There are many types of fungi on our bodies and in the environment that do not pose problems to our health. However, in the right conditions, some can cause infections and diseases that affect the scalp and other areas of the body.
Most fungal infections are more likely to occur in people with weakened immune systems. Those who are concerned about their risk of a fungal infection should talk to their doctor about their bedding and if sleeping with wet hair could pose a risk to their health.
Many people believe that sleeping with wet hair can increase the risk of developing a cold. However, there is no scientific evidence that wet hair directly causes any type of illness, including the common cold.
Common colds can occur around two to three times per year in most adults. Colds are caused by a viral infection of the respiratory system, as they travel within air droplets released by coughing or sneezing. It has been long thought that exposure to cold temperatures causes the common cold, but there is little evidence to support that theory.
People may sleep with wet or damp hair for a variety of reasons. Some may choose to shower at the end of the day as part of their relaxing bedtime routine and feel more comfortable getting directly into bed with wet hair. Some hairstylists may suggest sleeping with conditioned damp hair to enhance certain hairstyles.
Whether intentional or or not, there are steps you can take to make sleeping with wet hair a better experience overall.
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