Sweat Introduction Sweat is a clear, salty liquid. It is made by glands in your skin. Sweating is how your body cools itself. Sweating a lot is normal when it is hot or when you exercise. It is also normal if you are anxious or if you have a fever. If you often sweat too much or too little, it may be a sign of a problem. This reference summary will help you understand sweat. It explains what sweat does, problems related to sweating and when you should contact a health care provider. Sweat Glands & the Skin Sweat glands are special glands found in the skin. These glands produce sweat when the body gets too hot or is under stress. There are two types of sweat glands: eccrine glands and apocrine glands. Sweat Gland Eccrine glands are located all over the body. They open directly to the skin. These glands make and release sweat when the body gets too hot. Apocrine glands are mostly located where a lot of hair grows, such as the armpits, scalp, or groin. The glands open into hair follicles. These glands make and release sweat in response to stress. Sweat is sometimes called perspiration. It is mostly made up of water and salt. Sweat also contains small amounts of certain chemicals, including: Ammonia. Sugar. Urea. 1
Sweat leaves the sweat glands and the skin through tiny holes. These holes are called pores. You sweat mainly under your arms, on the soles of your feet and on the palms of your hands. When sweat mixes with bacteria on your skin, it can cause a smell. Bathing regularly and using antiperspirants or deodorants can help control the odor. Antiperspirants are different from deodorants. Deodorants can eliminate odor but not perspiration. What Sweat Does Sweat is the body s response to heat, anxiety, fear or even illness. Sweating helps keep the body at a normal temperature. For most people, a normal body temperature is around 98.6 degrees Fahrenheit. A little higher or lower is also normal. The part of the brain that controls body temperature is called the hypothalamus. If your body gets too hot, the hypothalamus sends a message to the rest of the body. This message tells the body to sweat. The sweat glands in the skin make the sweat and release it. Once the sweat gets to the top of the skin, it evaporates. This cools the skin and the body back to a more normal temperature. Sweating a lot is normal when it is hot or when you exercise. Just make sure to drink a lot of water or sports drinks to prevent dehydration. Dehydration is a condition caused by the loss of too much water from the body. It can cause serious health problems if it is not treated. Sweating a lot is also normal if you are anxious or have a fever. It happens during menopause, as well. Menopause is the time of life when a woman s ovaries stop making hormones. Menstrual periods also stop. Natural menopause often happens around age 50. Sometimes sweating too much or too little can be a sign of a health problem. The next two sections talk about these problems. 2
Sweating Too Much Sweating a lot when you aren t exercising or when the temperature isn t hot is called hyperhidrosis. Hyperhidrosis often affects the armpits, soles of the feet and palms of the hands. People whose bodies create too much sweat may have a hard time controlling perspiration. Because of this, people with hyperhidrosis may have problems with socialization. Normal everyday activities, such as shaking or holding hands, can be stressful or embarrassing for people with hyperhidrosis that affects the hands. Stress can make hyperhidrosis worse. Writing, using a keyboard or a playing a musical instrument can be very hard. Patients with hyperhidrosis may have to change their behavior to get through normal daily activities. For example, the patient may use pads to prevent ink from smearing when writing. He or she may have napkins with them at all times. Patients often need to change their undergarments and socks. They may not be able to wear sandals or flip-flops. In severe cases, sweat may drip from the body. Embarrassing or difficult social situations are only one problem that hyperhidrosis can cause. Without regular washing and drying, fungal infections can develop. These fungal infections can cause a bad smell. Hyperhidrosis also creates a higher risk of bacterial infections and heat rash. This is why people who suffer from this condition need to pay extra attention to their hygiene. The reason for hyperhidrosis in some people is not known. But the condition can run in families. Hormonal problems can cause the body to sweat too much. Check with your health care provider if you have sudden sweating that is more than normal. It could be the sign of diabetes, overactive thyroid, or an infection. Certain drugs, foods and beverages can make people sweat more or make their sweat smell different. When these cause the sweating, it can be controlled by changes in diet. 3
Medicines, medical procedures and even surgery, in severe cases, can treat hyperhidrosis. Talk to your health care provider for more information on treatment options. Sweating Too Little Sweating too little is called anhidrosis. Anhidrosis can cause the body to overheat. This may lead to serious health problems. Anhidrosis can affect the entire body or just one area. It can also affect small patches all over the body. If anhidrosis only affects parts of the body, the unaffected parts may make more sweat. This means a person with anhidrosis may sweat more than normal on some parts of the body, but not at all on others. Besides little or no perspiration, symptoms of anhidrosis may include: Dizziness. Feeling hot. Flushing. Muscle cramps or weakness. Causes of anhidrosis include dehydration, burns, and certain medicines. It may also be caused by some skin and nerve disorders. Examples of some nerve disorders are: Horner syndrome, which damages nerves in the face and eyes. Parkinson s disease, which affects nerve cells in the brain that control muscle movement. Ross syndrome, which affects nerves in the limbs. Anhidrosis may also happen if the nerves that control sweating are damaged due to an illness. Some examples of illness that can damage these nerves are: Alcoholism. Amyloidosis. Diabetes. Rare metabolic diseases, like Fabry disease. Small cell lung cancer. 4
Amyloidosis happens when abnormal proteins build up and form deposits. The deposits can collect in organs such as the kidneys and heart. This can cause the organs to become stiff and unable to work the way they should. Fabry disease is an inherited disorder, meaning it is passed on from parent to child. It results from the buildup of a particular type of fat in the body s cells. It can cause life threatening complications, such as kidney damage, heart attack and stroke. Treatment is not usually needed for anhidrosis that affects only a small part of the body. If anhidrosis affects a large part of the body, it often gets better when the underlying cause is treated. If you have anhidrosis, it is important to prevent heatrelated illnesses. You can do this by: Monitoring your level of activity. Staying hydrated. Staying indoors during the hottest part of the day. Wearing loose, light-weight and light-colored clothing. When to Call a Health Care Provider See a health care provider if: Sweating is interfering with your daily activities. You are sweating more than usual. You have night sweats for no known reason. See a health care provider if you experience a change in body odor, as well. Changes in body odor may be caused by certain medical conditions, such as kidney failure. You should also see a health care provider if you only sweat a little, especially while exercising. See a health care provider if you: Sweat less than usual. Have the signs of heat-related illness. 5
Signs of heat-related illness are: Fainting or dizziness. Fever. Flushed skin. Headache. Muscle cramps in the abdomen, arms or legs. Nausea or vomiting. Paleness. Rapid pulse. Weakness. Heatstroke is the most serious type of heat-related illness. Heatstroke is when the body is overwhelmed by heat. It can be life threatening and requires emergency medical attention. Seek emergency medical attention if you or someone you love has symptoms of heatstroke. Symptoms include: A high body temperature of 103 F or higher. Confusion or agitation. Dizziness. Headache. Nausea or vomiting. Red, hot skin that lacks sweat. Rapid heart rate. Tiredness. Unconsciousness. Summary Sweat is a clear, salty liquid. It is made by glands in your skin. Sweat is the body s response to heat, anxiety, fear or even illness. Sweating is how your body cools itself. It helps keep the body at a normal temperature. Sweating a lot is normal when it is hot or when you exercise. It is also normal if you are anxious or if you have a fever. But, if you often sweat too much or too little, it may be a sign of a problem. 6
Sweating a lot when you aren t exercising or when the temperature isn t hot is called hyperhidrosis. Hyperhidrosis often affects the armpits, soles of the feet, and palms of the hands. Sweating too little is called anhidrosis. Anhidrosis can cause the body to overheat. This may lead to serious health problems. See a health care provider if sweating is interfering with your daily activities. Also see a health care provider if you: Are sweating more or less than usual. Have night sweats for no known reason. Have the signs of heat-related illness. Experience a change in body odor. 7