What is night sweats? How much sweating is normal?

Night sweating in the medical sense means sweating regularly over a long period of time while sleeping, which is usually viewed as painful by those affected. Up to half a liter of fluid loss is considered normal, although the exact amount depends on body weight, for example. However, if you regularly wake up bathed in sweat, you should seek medical advice. As a rule of thumb, if night sweats last longer than three weeks, you should see a doctor. If there are other additional symptoms, they may also occur earlier.

Causes of night sweats

The causes of night sweats can be varied. Often it's just the conditions in the bedroom . Especially on hot days, the rooms become very hot and are difficult to cool down without air conditioning. The high temperature causes the sweat glands to become active. The only thing that helps here is to dress as loosely as possible and sleep with a thin blanket or no blanket at all.

By the way, a blanket that is too thick is a common reason for night sweats, even in winter. We like it cozy and warm in bed. The thick blanket may seem comfortable at first, but due to the heat that our body continually gives off, it heats up more and more as the night goes on under the blanket. In addition, thick blankets are heavy and limit our freedom of movement.

Bad air in the bedroom can also lead to night sweats. Experts therefore recommend ventilating the room briefly before going to bed so that there is an exchange of air. Unless the temperature outside is below zero, it would be even better to sleep with the window open - provided the noise from outside is not so strong that it reduces the quality of sleep.

Ideal room temperature for sleeping

The room temperature has a significant influence on the quality of sleep and, of course, on whether we sweat at night or not. Experts recommend a room temperature of 15 to 18 degrees Celsius in the bedroom, although the ideal temperature always depends on your personal feeling of cold.

Anyone who finds these temperatures unpleasantly cold will not be able to sleep well and may increase them. Especially when the heating is running, many people find it difficult to choose a comfortable, constant temperature throughout the night. This should be practiced so that the heating does not cause night sweats. A thermometer in the bedroom helps.

Unhealthy lifestyles promote night sweats

We often intuitively adjust the environmental conditions so that we get the best possible sleep. Then it is the (unhealthy) lifestyle that makes us sweat at night. A classic example is excessive alcohol consumption. But smoking and heavy or spicy food can also be a cause of night sweats.

Overweight people in particular sweat profusely at night. This is usually directly related to the high body mass. The only long-term solution is to reduce weight. Overweight people generally sleep more restlessly, snore more often and, on average, have more pauses in breathing during sleep (sleep apnea) than people of normal weight.

Night sweats as a symptom

If night sweats are not a well-known phenomenon and the problem cannot be brought under control by adjusting your sleeping habits, then it is reasonable to suspect that night sweats are a symptom of illness. There are numerous illnesses that can trigger night sweats. Doctors then speak of nocturnal hyperhidrosis.

This is typical, for example, for infectious diseases. The body reacts to this with an increased temperature in order to ward off the pathogens. At the same time, our sweat glands produce more sweat so that the body does not overheat. This applies to acute infections such as the flu as well as chronic infectious diseases such as AIDS and tuberculosis.

Metabolic diseases such as diabetes, autoimmune diseases such as rheumatoid arthritis, hormonal fluctuations such as those that occur during menopause and cancer can also be responsible for night sweats.

Another common cause is psychological stress and illness. Stress and fear are typical factors. At night there are no distractions from everyday life and the body processes its problems. Night sweating is an external characteristic of this processing process.

Sometimes sweating while sleeping is a side effect of medication. For example, blood sugar lowering agents, fever lowering agents, antidepressants, beta blockers and hormone preparations cause night sweats.

What to do about night sweats?

If night sweats are not a temporary phenomenon and are accompanied by other symptoms, a medical examination should always take place in order to find out the cause and combat it medically.

More tips against sweating at night

Here are more tips to prevent night sweats:

• Ventilate the bedroom before going to bed
• Darken the bedroom on warm summer days to ensure a comfortable sleeping temperature
• If you have one, use air conditioning to continuously cool down the bedroom
• Choose your duvet and pajamas according to the season
• Avoid physical exertion and excitement at least an hour before bedtime
• Don't drink alcohol in the evening
• Avoid overly fatty or spicy foods in the evenings