Night Sweats: Causes, Symptoms and Treatment

Waking up sweating because of a duvet that's too warm, a spicy dinner, or a bit too much alcohol. All of these things can be the cause of night sweats. However, if night sweating occurs over a longer period, we call this nocturnal hyperhidrosis. The reasons for this can vary widely. We'll show you what you can do and what the possible causes are.

What are night sweats?

Sweating is a natural process. It's how the body transfers excess heat from the inside out, maintaining the necessary temperature balance. This regulating system is important during physical activity, hot weather, or fever, among other things. We also sweat during sleep, but we don't notice it immediately. Under certain circumstances, however, the body releases more heat. For example, when the bedroom is very warm, when too much alcohol has been drunk, or when dinner was particularly spicy. But medications that stimulate metabolism, illnesses, or stress can also cause you to wake up sweating.

There are around two million sweat glands spread across your entire skin. When heat needs to be released, the glands secrete fluid. This evaporates on the surface of the skin, drawing heat away from the blood vessels in the skin. Sweat consists not only of water but also of salts and various minerals such as calcium and magnesium. Sweat also contains substances that support the body's immune system. This allows bacteria and fungi to be repelled from the skin. Certain toxins are also rendered harmless in this way.

What are night sweats from a medical point of view?

From a medical point of view, we speak of night sweats when sweating occurs at night over a longer period of time. This can sometimes be so intense that pyjamas and bedding become soaked. Those affected sometimes wake up and have to change clothes or even take a shower. This heavy sweating is not caused by an overly high room temperature or a duvet that's too warm. People who suffer from night sweats are usually tired and drowsy the following day. Excessive sweating usually doesn't occur during the day. Night sweats are therefore not the same as other sweat-production disorders that occur independently of specific times (hyperhidrosis). Nocturnal sweating is also known as nocturnal hyperhidrosis.

Causes of waking up sweating

Night sweats are often caused by stressful life situations or unfavourable sleeping conditions. But hormonal fluctuations or serious illnesses can also lead to nocturnal sweating.

These are the most common causes of night sweats:

• Unsuitable sleeping conditions such as: a room temperature that's too high, a duvet that's too warm, humidity that's too high
• Drinking alcohol, consuming nicotine, caffeine, and spicy food.
• Certain medications
• Infectious diseases
• Hormonal changes and metabolic disorders
• Autoimmune diseases
• Cancer
• Psychological stress and illnesses
• Neurological diseases

Which medications can make you wake up sweating:

Sometimes night sweats are triggered by certain medications. These are medications that affect the autonomic nervous system, both the sympathetic and parasympathetic parts. The unwanted sweating sometimes only occurs at the start of the medication, while in other cases it can begin when the medication is taken incorrectly or for a prolonged period. After consulting a doctor, they may prescribe a different, equivalent medication. Medications that can cause night sweats in some people include:

• Antidepressants
• Atypical antipsychotics
• Antipyretics such as paracetamol or acetylsalicylic acid
• Medications that lower blood sugar
• Medications for asthma and bronchitis
• Eye drops for glaucoma
• Hormone-blocking medications, for example for treating breast cancer or prostate cancer
• Hormone preparations for endometriosis

Waking up sweating due to psychological or neurological conditions:

Because sweat production is regulated by the autonomic nervous system, psychological processes also affect it. For example, even more stress hormones are released at night if the day's problems can't be let go of. It's also possible for sleep disorders or nerve conditions to lead to nocturnal sweating. Among others, these diagnoses are often accompanied by nocturnal sweating:

• Burnout syndrome
• Anxiety disorders
• Sleep disorders
• Neurological diseases such as Parkinson's disease or spinal cord injury

Infections that cause night sweats:

The immune system responds to infections by releasing substances that raise body temperature. This warming activates certain defence mechanisms, and acute infections are often accompanied by heavy sweating at night. Some chronic illnesses that permanently challenge the immune system can lead to a continuously elevated body temperature. Infections that lead to nocturnal sweating include:

• Influenza (viral flu)
• Endocarditis (inflammation of the heart lining)
• Tuberculosis (TB)
• Lyme disease
• Glandular fever (Pfeiffer's disease)

Autoimmune diseases that trigger nocturnal sweating:

Normally, our immune system fights off foreign invaders or substances. In autoimmune diseases, this system sometimes malfunctions and the body attacks its own cells. In some diseases, this overreaction of the immune system leads, among other things, to a general feeling of illness combined with nocturnal sweating.

Autoimmune diseases that are often accompanied by nocturnal sweating include:

• Rheumatism
• Wegener's disease
• Arteritis
• Polymyalgia rheumatica
• Glandular fever (Pfeiffer's disease)

Waking up sweating due to hormonal fluctuations or metabolic problems:

Both hormones and metabolism affect the body's heat regulation. If there's a disorder in either area, sweat production can be stimulated, so that you sweat even at night, i.e. at rest. These conditions and medical issues that are often accompanied by nocturnal sweating include:

• Hyperthyroidism (overactive thyroid)
• Diabetes
• Menopause

When should you see a doctor about night sweats?

When we sleep, it's usually completely normal to sweat a little. This is the body's way of regulating temperature. What's more, you can make things much more comfortable for yourself with a temperature-regulating duvet. However, if night sweats occur regularly over a longer period, or if the symptoms are very severe, you should consult a doctor. This is especially true if there are other symptoms as well.

Diagnosing nocturnal sweating

During a consultation with a doctor, they will get a thorough picture of your medical history and current symptoms. The doctor will also ask questions about your current life situation. There can be many reasons for nocturnal sweating.

A common reason is regular alcohol consumption, but stress and illnesses such as heart failure, HIV infection (AIDS), or tumours can also trigger nocturnal sweating. It's also important for doctors to know whether and which medications are being used, as some medications also trigger nocturnal sweating.

Treating night sweats

Night sweats disappear once the underlying illness has been successfully treated. For example, if an infection was the cause of the increased night sweats, the symptom will disappear once the illness has passed. If the sweating is caused by medication, the doctor can adjust the dosage or choose a different medication if necessary. If stress is the cause of night sweats, practising relaxation techniques can help many people. Psychotherapeutic support can also help with serious psychological problems. Night sweats are often simply caused by an unhealthy lifestyle. In that case, it's worthwhile to change your diet, avoid alcohol and nicotine, and include exercise in your daily routine.

Night sweats during menopause

Many women experience hot flushes and sweating during menopause. Symptoms such as sweating and a feeling of heat also often occur during sleep. However, these symptoms don't occur in every woman. The intensity of these symptoms varies greatly from person to person. During this period, which is characterised by hormonal fluctuations, female sex hormones such as progesterone and oestrogen are produced only in small amounts or not at all. As oestrogen levels drop, stress hormones such as adrenaline increase. This often leads to increased sweat production during the night. If the symptoms are particularly severe, you should discuss with your doctor what options are available to relieve them. If the symptoms are mild, try a washable duvet, recommended by our night-sweat experts.

Frequently asked questions about night sweats

How long do night sweats last?

There are many possible triggers for night sweats. It can, for example, be caused by a physical illness such as an infection or an autoimmune disease. But hormonal causes or medication side effects can also lead to nocturnal sweating and disrupt restful sleep. Once the underlying illness or condition is no longer present, the sweating usually stops. If night sweats occur only occasionally, eating overly spicy food or drinking too much alcohol may sometimes be the cause. This food should be avoided if it affects you.

What helps against nocturnal sweating?

Night sweats can be a symptom of an illness or have harmless causes. If you have the flu, for example, the night sweats will stop as the illness subsides. If someone is taking medication that causes heavy sweating, the doctor can change the dosage or prescribe a different medication if necessary. Night sweats during menopause can be relieved by temporarily taking hormones. Homeopathic remedies or acupuncture can also help many people with excessive sweating. It's best to consult your doctor or homeopath about this. If someone suffers from night sweats due to stress, regular relaxation exercises can help. With mild symptoms, you can also choose a different type of duvet with more temperature regulation.

Why do you sweat at night when you're stressed?

Stress and worries in daily life can rob you of sleep. What's more, an increased release of stress hormones during sleep often also causes excessive sweating. Sweat production is regulated by the autonomic nervous system. The sympathetic nervous system is responsible for regulating many involuntary bodily functions. These include the release of adrenaline and noradrenaline, an increased heart rate, and the narrowing of blood vessels. This in turn leads to dilation of the blood vessels in the skin, which is why sweat breaks out under stress or anxiety, even during sleep. If stress-related night sweats are keeping you from sleeping, it's best to learn relaxation techniques and practise them regularly.

Why do you get night sweats when you have the flu?

By increasing sweat production, the body releases excess heat to the outside. When you're ill and develop a fever, your body temperature rises accordingly. This is a response from our immune system to the infection. Up to a certain temperature, fever is an important part of the immune system. By then sweating, even at night, the body can release the fever heat. This often already indicates an initial improvement in the illness.

What can you do yourself against night sweats?

If a serious illness isn't the cause of the night sweats, you can use these tips to sleep well again:

• Drink little or no alcohol in the evening.
• Avoid caffeinated drinks.
• Don't smoke.
• Exercise regularly and often.
• If you're overweight, try to reduce your body weight.
• Don't wear tight sleepwear. It's better to wear light clothing made from natural materials.
• Don't keep the bedroom at a high temperature. 18 degrees is recommended.
• Choose a duvet with temperature regulation and a breathable fabric.
• Relax before going to bed. Calming music, a warm bath, or relaxation techniques help.
• Drink sage tea in the evening. It can help prevent nocturnal hyperhidrosis (night sweats).

Sources:
Quest.nl: 10 things about sweating
Isala Hospital: Hyperhidrosis
Dutch College of General Practitioners (NHG)
Textbook of Internal Medicine, Author: Joost van der Meer - Edition: 2017