No sweat, or sweat? Is sweating healthy or unhealthy? What is your sweat telling you?

by Rebecca Lobo August 8, 2025

Sweat, not something we talk about much or know much about, but we spend a lot of time, angst, and money addressing it. So, let’s sweat the details…

Sweat secretion is controlled by the nervous system, specifically the central and autonomic nervous systems.

Science has artificially broken down the nervous system into 2 main parts: central (brain and spinal cord) and peripheral (everything else). The peripheral nervous system is further broken down into the somatic and autonomic nervous systems. The somatic nervous system is made up of the nerves that innervate all the muscles you can control and the organs responsible for sound, smell, taste, and touch. The autonomic nervous system innervates muscles you cannot control and connects your brain to most of your internal organs. Your autonomic nervous system is further broken down into your sympathetic (fight or flight), parasympathetic (rest and digest) and enteric nervous systems. The autonomic nervous system controls involuntary functions such as heart rate, blood pressure, pupil dilation, digestion, breathing, temperature regulation, and mucus, tear, and sweat production.

What is sweat?

Sweat, or perspiration, is the fluid secreted by eccrine and apocrine sweat glands deep within your skin (dermis layer). Sweat travels through tiny tubes called sweat ducts until it reaches the surface of your skin and exits through openings on your skin called pores. (Pores are too small to be seen with the naked eye. So, if you’re concerned about pore size, what you’re worrying about is not actually a physiological pore, but simply a slight depression of the skin surface containing many physiological pores.)

What is in your sweat?

Sweat is mostly water and sodium chloride, but also contains proteins, fats, carbohydrates, and minerals. Importantly, just like other bodily secretions such as tears, saliva, earwax, and mucus, your sweat contains antimicrobial proteins that protect you from infection by microbes (bacteria, fungi, and viruses) in the environment.

Why does your body sweat?

Sweating is primarily a way to cool your body and regulate your body temperature. Whenever your body temperature begins to increase, your autonomic nervous system stimulates your eccrine sweat glands (of which there are 2-4 million in the human body) to secrete sweat. As sweat evaporates, your body starts to cool down.

Besides thermoregulation, sweat also hydrates your skin and protects you from infection.

How does sweat affect body odor?

Sweat contributes to body odor when bacteria on your skin metabolize it. But, body odor is affected by many other factors including medical conditions, such as kidney failure and diabetic ketoacidosis, diet, cosmetics, medications, and the microbes living in and on you. Anti-perspirants and deodorants are the cosmetic industry’s solution to sweat and body odor.

What’s the difference between antiperspirants and deodorants?

Antiperspirants stop sweat production by using aluminum salts to block the physiological pores on the outer layers of your skin.

Deodorants do not block sweat production. Instead, deodorants mask the odors caused when bacteria living on your skin metabolize your sweat using fragrances and essential oils. Deodorants can also contain ingredients, such as baking soda and mandelic acid, that change the pH of your skin, making it inhospitable for odor-causing bacteria to thrive. You’re in a relationship with the microbes living in and on your body. So, using antiperspirants and deodorants changes your skin microbiome, which in turn will have an effect on your health, especially if you’re using these products over your whole body.

Is sweating healthy or unhealthy?

The beauty industry treats sweating and the resulting body odor as merely an embarrassing bodily function that needs to be prevented and/or masked. (“Horses sweat, men perspire, women glow”.) But, how much you sweat, when and where you sweat, and what your sweat smells like says a lot about your health and merits curiosity and investigation. For example, excessive sweating on the face, head, and trunk and less than normal sweating on hands and feet is an early sign of Parkinson’s disease.

So, before you use whole body antiperspirants and deodorants to silence and/or mask your body, ask yourself what your sweat might be trying to tell you. You might just save your life or, at the very least, time, money, and energy.

What is your sweat telling you?

Abnormal sweating can be indicative of hormonal imbalance and immune, skin, and nervous system dysfunction.

Dysautonom ia (dis’-oughta-know’-me-uh) or dysfunction of the autonomic nervous system is a rarely diagnosed, but common cause of abnormal sweating. There are many types of dysautonomia, including p ostural orthostatic tachycardia syndrome (POT S) and ne urogenic orthostatic hypotension (nO H). The leading causes of dysautonomia are d iabet es and Sjo gren’s disea se.

Excessive sweating (Hyperhidrosis)

Hyp erhidrosis is a serious medical condition characterized by excessive sweating not triggered by heat or physical exertion. Primary focal hyperhidrosis refers to excessive sweating that is not caused by another medical condition or drug side effects. Excessive sweating is the medical condition itself. Primary focal hyperhidrosis often begins in childhood or adolescence and is characterized by excessive sweating that occurs symmetrically on hands, feet, underarms, face, and head. People with primary focal hyperhidrosis have episodes of excessive sweating at least once a week, but usually do not experience excessive sweating while sleeping. Secondary generalized hyperhidrosis is caused by an underlying medical condition or a medication. Unlike primary focal hyperhidrosis, secondary generalized hyperhidrosis usually starts in adulthood and is characterized by excessive sweating that’s not limited to specific parts of the body and can occur during sleep. For a list of d rug s and di sease s that can cause hyperhidrosis, please visit w ww.sweathelp .org.

No sweating (Anhidrosis / Hypohidrosis)

Anhidrosis can affect small or large areas of the body and can be caused by one or more factors. Anhidrosis can occur because of dehydration, nerve damage, skin damage, an inherited defect or clogged or obstructed sweat glands, or as a side effect of certain medication (antipsychotics, anticholinergics, and calcium-channel blockers). Anhidrosis can also occur as an isolated condition (hypohidrotic ectodermal dysplasia) or as part of a group of symptoms associated with another disease, such as Sjog ren’s di sease. (If you have Sjogren’s, please take 20 minutes to complete the Livin g with Sjogren’s Patient Survey from the Sjogren’s Foundatio n before September 4.)

People with severe anhidrosis are at high risk for heat-related illnesses such as heat exhaustion and heat stroke. In extreme cases, or if these heat-related illnesses are not treated appropriately, coma or death can result.

How has sweating impacted your life?

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