Sweat is a salty liquid that your skin’s glands produce. Sweating (also called perspiring) occurs when your body becomes heated and attempts to cool itself. As such, you might notice that you sweat on hot days, when exercising, when experiencing anxiety, or when you have a fever.

This article explains sweat’s structure, function, and causes. It also covers conditions associated with sweat.

The Production of Sweat

Glands in your skin produce sweat. There are two types of sweat glands: eccrine and apocrine.

Apocrine glands are an extension of hair follicles. They release a cloudy liquid in hairy body parts, like the armpits and groin. However, the liquid they produce does not help regulate body temperature.

Eccrine glands release water that contains electrolytes (minerals such as sodium that have an electrical charge when dissolved in water). The liquid these glands produce works to cool the body.

Eccrine glands are located all over the body in the skin’s epidermis (outermost layer) and dermis (middle layer). These glands develop in utero at around three months into gestation and are fully mature by eight months.

Sweat mainly consists of water. But it also contains:

  • ElectrolytesPheromones (substances that trigger a social response in other humans)BacteriaToxins

Function of Sweat

Sweat’s primary role is thermoregulation (regulating body temperature). As sweat releases onto the skin, it evaporates and cools the body. Without sweat, humans would overheat and die.

In addition to cooling the body, researchers believe sweat has even more roles, including:

  • Excretory function to clear toxins from the body
  • Maintaining skin health through moisturization
  • Micronutrient balance (sodium chloride and trace minerals)

What Causes Sweating?

Because sweating’s primary role is cooling the body, you will usually sweat when your body experiences excessive heat. Sweating may occur for several reasons, including:

  • Elevated environmental temperature
  • Exercise
  • Anxiety
  • Fever
  • Hormonal fluctuations, like during menopause
  • With some health conditions

Associated Conditions

Though sweating is a normal human function, it can also be a side effect of some health conditions. Some of these conditions result in excessive sweating, while others result in too little sweating.

Hot Flashes

Hot flashes are sudden and intense flashes of heat in the body. They usually last for a few minutes at a time. Sweating often accompanies hot flashes.

Hot flashes commonly occur with menopause, but they can occur for other reasons, including:

  • Cancer treatments like chemotherapy and radiation
  • Hormone therapy
  • Side effects from medication such as opioids, tricyclic antidepressants, and steroids
  • Depression and anxiety

Most people deal with hot flashes by wearing layers they can take off, using fans and cool compresses, hydrating, and avoiding triggers.

Prickly Heat

Prickly heat (also called heat rash or miliaria) is a rash that occurs when sweat glands get clogged and trap sweat in the skin. Prickly heat is more common in children than adults. Symptoms include:

  • ItchingDiscomfort that feels like pricklingSkin bumps or blistersLarge, red rash

To prevent prickly heat, wear loose-fitting clothing, keep yourself cool in hot weather with baths and showers, change out of sweaty clothes or wet diapers, and stay hydrated.

Hyperhidrosis

Hyperhidrosis (excessive sweating) is different than profuse sweating from something like exercise. Instead, excessive sweating from hyperhidrosis occurs due to another health condition or for no apparent reason.

If you have hyperhidrosis, you may visibly sweat without exertion or exposure to heat. Often, the condition interferes with everyday life. For example, your skin may turn soft and white and peel. And you may be more prone to skin infections.

Hyperhidrosis treatment includes:

  • AntiperspirantsMedicationSurgical sweat gland removal or surgery to stop nerve signals to sweat glandsMedical devices to destroy sweat glands

Hypohidrosis and Anhidrosis

Hypohidrosis is the opposite of hyperhidrosis—it is reduced sweating. Anhidrosis, the absence of sweating, is the most extreme form of decreased sweating. Because sweating is critical for controlling your body’s temperature, these are concerning conditions that can threaten your life.

Anhidrosis is rare. It most often occurs as the result of severe injury to the skin, including:

  • Burns
  • Radiation
  • Infection
  • Inflammation
  • Some medications
  • Health conditions that affect nerves, connective tissue, or sweat glands

People who do not sweat enough need to take extra care not to overheat. That means staying hydrated and avoiding overexertion and high temperatures.

Cold Sweats

Diaphoresis (cold sweats) sometimes occurs when you feel anxious or stressed. In addition, it can happen in response to a medical condition, like shock or a heart attack. Fevers can also lead to cold sweats.

Because cold sweats can indicate a medical emergency, seek medical attention if they are accompanied by the following:

  • ConfusionChest, abdominal, or back painHeadacheBloody stoolsPersistent vomitingShortness of breathWeak pulseDrug use

Frey Syndrome

Frey syndrome (also called gustatory sweating) is a condition that causes you to sweat after eating. Sweating usually appears on the face and occurs after eating spicy foods. This condition is more likely to develop in people who have had surgery near the parotid (salivary) glands.

Treatment for Frey syndrome includes medications that block nervous system activity or sweating or surgical removal of the affected skin.

Night Sweats

Night sweats can occur with hot flashes while you sleep. However, night sweats are more than mild sweating—often, with night sweats, you wake in soaked bedding and clothing. The most well-known cause of night sweats is hormonal imbalance, like those that accompany perimenopause and menopause.

Other night sweat causes include:

  • IllnessInfectionCancerLow blood sugarHormone disordersNeurological conditionsMedication side effectsCancer treatmentCaffeine, alcohol, or drug use

If you experience night sweats, talk to a healthcare provider to identify the cause.

Managing Sweat

Sweating can be uncomfortable and even embarrassing. But remember, everyone sweats, and it’s a normal, necessary bodily function. Even so, there are some ways to manage sweat, including:

  • Use antiperspirant or deodorant.Identify triggers and avoid them (for example, spicy foods, caffeine, or alcohol).Wear sandals or natural shoe materials like leather that allow air circulation.Change clothing and socks when they are wet.

When to See a Healthcare Provider

If you experience excessive sweating or do not sweat enough, it’s a good idea to see a healthcare provider. You may fall on a spectrum of typical sweating, but because over- and under-sweating can indicate some health conditions, it’s best not to take a chance.

Summary

Sweat is a bodily function that keeps human bodies from overheating. Sweat consists of water, electrolytes, pheromones, bacteria, and toxins. Most commonly, heat and exertion cause sweating. However, some health conditions can lead to excessive sweating and not sweating.