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I sweat a lot in my sleep, and it's especially bad on hot days, which is a real problem. This article explains the causes and countermeasures for excessive night sweats for people with this concern.
What are night sweats in the first place?
Night sweats are a physiological phenomenon that occurs in anyone, regardless of age or season.
They play a role in regulating body temperature by releasing heat accumulated in the body during the day, and healthy adults are said to sweat about one cup per night. Therefore, sweating during sleep itself is not a problem.
However, severe night sweats that require a change of clothes are sometimes referred to as "toukan" (盜汗) in traditional oriental medicine and are distinguished from normal physiological sweating as an undesirable form of sweating.
Toukan (盜汗) means that essential body fluids and energy are secretly stolen while sleeping, and it can be a symptom of an underlying illness, so caution is advised.
Causes of severe night sweats
Severe night sweats, such as needing to change clothes, waking up to find bedding soaked with sweat, or being woken up repeatedly by night sweats, are primarily caused by the following:
- Excessive stress
- Excessive alcohol consumption
- Diseases such as sleep apnea syndrome
- Sleep environment
- Hormonal imbalance during pregnancy and menopause
- PMS (premenstrual syndrome) before menstruation
Excessive stress
Night sweats are related to the activity of the parasympathetic nervous system, which is part of the autonomic nervous system.
The autonomic nervous system consists of the parasympathetic nervous system, which dominates during sleep, and the sympathetic nervous system, which dominates during the day. When these two work in balance, both mind and body can function well.
However, excessive stress can disrupt the autonomic nervous system, making it difficult to switch between the sympathetic and parasympathetic nervous systems. As a result, body temperature regulation during sleep may not occur smoothly, leading to excessive night sweats.
Excessive alcohol consumption
When alcohol is consumed, a harmful substance called "acetaldehyde" is produced in the body.
Acetaldehyde is broken down by the liver and other organs and expelled from the body through sweat, urine, and breath. Therefore, if you consume too much alcohol, a large amount of acetaldehyde is produced, and the body's attempt to break it down can increase night sweats.
Diseases such as sleep apnea syndrome
Severe night sweats (盜汗) can also appear as a symptom of sleep apnea syndrome, hyperhidrosis, or certain infectious diseases.
Sleep apnea syndrome is a condition where breathing repeatedly stops during sleep. Medically, it is diagnosed as mild if there are 5 or more apneas per hour, and the severity increases to moderate or severe with more frequent episodes.
When apnea occurs during sleep, the body becomes hypoxic, which can lead to discomfort and increased night sweats.
In addition, if you cannot identify the cause of severe night sweats, such as a high room temperature, stress, or excessive alcohol consumption, it may be due to an underlying medical condition affecting the autonomic nervous system, thyroid, or an infection.
If severe night sweats persist daily or do not subside even after changing your sleep environment, it is advisable to seek medical attention promptly.
Sleep environment
Maintaining a comfortable bedroom temperature and humidity is crucial for smooth body temperature regulation during sleep.
Bedroom temperatures vary by season, typically around 25-27°C in summer and 15-18°C in winter. Humidity should ideally be 50-60% year-round. Additionally, the microclimate between the bedding and the person, known as bedding temperature, is considered comfortable at around 30°C and humidity at around 50%.
However, keeping the air conditioner at a constant temperature throughout the night may sometimes hinder proper body temperature regulation during sleep. In such cases, it's advisable to utilize timer functions or "sleep mode" settings that can adjust room temperature between bedtime and after falling asleep, depending on the season.
It is also important to choose bedding and clothing appropriate for the room temperature and humidity. Sleeping in a sleep environment that is not suitable for the season, such as using winter bedding on a hot day or wearing thick pajamas, can lead to increased night sweats.
Hormonal imbalance during pregnancy and menopause
Hormonal imbalances, such as those during pregnancy or menopause, are also factors that increase the amount of night sweats. When hormonal balance is disturbed, it can adversely affect the autonomic nervous system, leading to increased perspiration.
Especially in early pregnancy, not only is there a hormonal imbalance, but basal body temperature also rises, which will likely increase the amount of night sweats.
During menopause, hormonal imbalances due to aging can lead to various physical and mental symptoms, including muscle pain, irritability, and hot flashes. Increased sweating is one of these symptoms and can be a cause of excessive night sweats.
PMS (premenstrual syndrome) before menstruation
For women, PMS (premenstrual syndrome) that occurs before menstruation is also one of the causes of temporary severe night sweats.
Premenstrual Syndrome (PMS) refers to physical or mental discomfort that begins 3 to 10 days before menstruation. Although there are individual differences, women's body temperature rises by 0.3 to 0.5 degrees during the premenstrual high-temperature phase, leading to increased night sweats.
It should be noted that the cause of Premenstrual Syndrome (PMS) is not only changes in female hormones but is also said to be related to various other factors.
What happens if severe night sweats are left untreated?
Leaving severe night sweats untreated can negatively affect your health and cause problems, such as the following:
- Decreased sleep quality
- Cause of body odor and bedding odor
- Increased susceptibility to colds
- Increased risk of skin problems
1: Decreased sleep quality
Excessive night sweats can make the futon feel stuffy and uncomfortable. As a result, you may wake up in the middle of the night or have shallower sleep.
2: Cause of body odor and bedding odor
When bedding and pajamas get wet with night sweats, bacteria can multiply and become a source of odor. If bedding is not washed frequently, unpleasant odors can permeate, disrupting sleep.
Furthermore, if stress or excessive fatigue is the cause of night sweats, the odor of the sweat may become stronger.
3: Increased susceptibility to colds
When a large amount of night sweat cools, it draws heat away from the body, making you more susceptible to colds.
4: Increased risk of skin problems
If severe night sweats are left untreated, they can also cause skin problems such as heat rash and acne.
Heat rash is a condition where the sweat ducts, which are the passageways for sweat, become blocked due to excessive sweating, leading to inflammation. It can be accompanied by itching, which can worsen sleep and thus lead to a decrease in sleep quality.
Severe night sweats may indicate an underlying illness.
If severe night sweats persist, there is a possibility that a serious illness may be hidden behind them.
Diseases that can cause severe night sweats include, in addition to sleep apnea syndrome mentioned earlier, hyperhidrosis (excessive sweating), autonomic dysfunction due to an imbalance in the autonomic nervous system, thyroid diseases such as collagen disease and Graves' disease, and reflux esophagitis.
There is no clear guideline for seeking medical attention, as the amount of night sweats varies greatly with age and individual. However, if you continue to experience bothersome symptoms such as night sweats, slight fever, fatigue, or weight loss, it is advisable to consult a medical institution.
Countermeasures for severe night sweats
When night sweats are severe, it is important to first consider what is causing them and then approach them accordingly.
Some easy countermeasures that can be adopted when night sweats are severe include the following:
- Stress relief
- Improvement of lifestyle rhythms
- Hydration before sleep
- Review of sleep environment and bedding
- Visiting a hospital
Stress relief
Chronic stress can disrupt the autonomic nervous system, leading to excessive night sweats.
Find stress relief methods that work for you, such as exercising, indulging in hobbies, or taking a long soak in the bathtub.
Improvement of lifestyle rhythms
Excessive alcohol consumption is one of the causes of severe night sweats. For those who have drinking habits or consume too much alcohol, try to review the amount and frequency, or create alcohol-free days.
Furthermore, if your waking, eating, and sleeping times are always inconsistent, your internal clock can easily get disrupted, leading to an imbalance in your autonomic nervous system. Improve your lifestyle rhythm, such as by going to bed and waking up early, to stabilize your autonomic nervous system.
A regular lifestyle also helps alleviate stress.
Some people might avoid drinking water before bed to prevent night sweats, but this is actually counterproductive. When you sweat, the sweat becomes sticky and increases discomfort.
Instead, it's recommended to drink a glass of water before bed. This reduces the viscosity of your sweat, making it evaporate more easily and less sticky.
Furthermore, dehydration can lead to sluggish blood flow and activate the sympathetic nervous system. Therefore, hydrating before sleep helps activate the parasympathetic nervous system, leading to better sleep.
Review of sleep environment and bedding
If you use bedding that is not suitable for the season or has poor breathability, the temperature inside the duvet can become too high or steamy, leading to increased night sweats. So, why not review your bedding?
Visiting a hospital
If severe night sweats persist to the point of requiring a change of clothes, even after reviewing your sleep environment and bedding, it could indicate a risk of illness. Therefore, do not self-diagnose and consult a medical institution.
How to choose bedding to combat night sweats
Here's how to choose bedding that can help with night sweats.
Breathability, moisture release
The biggest enemy for bedding throughout the year is humidity. Humidity accumulates in bedding not only during the humid rainy season and summer but also in winter when we sweat.
When you sweat during sleep, the inside of the futon tends to get stuffy and trap heat, but bedding with high breathability and moisture-wicking properties can release the sweat to the outside of the futon, improving sleep quality. Additionally, well-ventilated bedding helps reduce sweating, which can prevent excessive night sweats.
Contact cooling
For hot seasons, people who sweat a lot, or those who tend to feel hot, contact-cooling bedding is also recommended.
Contact-cooling bedding works by absorbing body heat when the body touches the fabric, creating a cool sensation. You can feel a pleasant coolness upon contact, which helps combat the heat.
However, there's a limit to how much heat the fabric can absorb, so once it's saturated, the fabric becomes lukewarm. This can lead to stuffiness, so when choosing contact-cooling bedding, it's recommended to select one with high sustainability.
Surprisingly Easy to Misunderstand!? How to Choose Summer Futons and Precautions for Contact Cooling
Check out items that can reduce night sweats
At Brain Sleep, we develop a variety of bedding tailored to our customers' sleep needs and concerns. Here, we introduce the features and benefits of recommended items that can help reduce night sweats.
For severe night sweats, understand the causes and countermeasures to aim for prevention.
Excessive night sweats can negatively affect sleep quality, so take measures to prevent them and enjoy a comfortable sleep life.
For hot summer nights, it's recommended to use a summer-specific duvet to regulate the temperature and humidity inside the bedding.
