Thermoregulation and Why Humans Sweat

Internal body temperature is controlled and regulated through a process called thermoregulation. The body constantly tries keeps its core temperature around 98.6 degrees, although it can waver within a narrow range between 91.76 and 100.72 degrees safely. Thermoregulation is part of a constant process the body goes through to stay in balance, called homeostasis. To maintain such a specific temperature range a part of the brain called the hypothalamus uses thermoreceptors (cells that sense temperature) throughout the body to determine what the body needs to do in order to heat up or cool off based on the environment it is in. The main reason why humans sweat is to cool off the body during times of high heat. The body also uses other processes like dilating or constricting blood vessels, shivering, and behavioral adaptations to control its internal temperature.[1]

How Sweating Cools the Body

When the environmental temperature exceeds a person’s internal body temperature various processes begin to induce sweating in order to keep that person’s core body temperature stable and cooler than their environment. Sweating is actually the only automatic way the body has to cool itself off when exposed to hot temperatures, which makes it very important for human survival. The body begins to sweat when a person’s brain senses that the body’s core temperature is beginning to rise, at which time it activates sympathetic cholinergic fibers, a part of the sympathetic nervous system that is responsible for activating sweat glands. Specifically, the body uses eccrine sweat glands, which are located all over the body, to regulate temperature. There is another type of sweat gland, called apocrine sweat glands, but they are not thought to be important in the process of thermoregulation. Once sweat glands are activated vasodilation occurs (expanding of the blood vessels) and sweat glands begin taking liquid from inside a person’s body and pumping it onto the surface of the skin. When the sweat is on the surface of the skin is evaporated as water vapor it transfers heat from the body to the surrounding environment. This essentially cools the human body as sweat transfers heat energy as it moves away from the body. When the body is cool enough the brain sends signals to sweat glands to stop producing sweat and the process is halted.[1]

Some people have a condition, called hyperhidrosis, that causes them to sweat too much. Luckily, hyperhidrosis is not particularly dangerous, although it is quite uncomfortable and can have a significant detrimental impact on a person’s quality of life. Hyperhidrosis is probably the most common sweating disorder, but there are other sweating conditions that cause people to sweat too little, have stinky sweat, or even have colored sweat.[1]

In addition to sweating because of high of surrounding temperatures, the body also produces sweat because of other factors that influence body temperature, like exercise and fever. Exercise, in and of itself, increases the body’s internal temperature and so the body responds by sweating to cool itself down.[1] In the instance of a fever, the body is trying raise its internal temperature in order to kill off intruders that are causing illness. Often sweating is a symptom of fever and it may also be a way the body uses to resolve a normal temperature once a fever is over, although the mechanism is not well understood.[3]

It is clear that sweating is an important process for regulating homeostasis in the human body. The brain and body work within a delicate balance to ensure that a person’s temperature is never too high nor too low and sweating is an essential part of its ability to do so.

Sources

1. Tansey, E. A., & Johnson, C. D. (2015). Recent advances in thermoregulation. American Physiological Society. Retrieved February 26, 2019, from https://doi.org/10.1152/advan.00126.2014.
2. Pariser, D. M. (2014). Hyperhidrosis (4th ed., Vol. 32). Philadelphia, PA: Elsevier.
3. Del Bene, V. E. (1990). Temperature. Clinical Methods: The History, Physical, and Laboratory Examinations. Retrieved February 26, 2019, from https://www.ncbi.nlm.nih.gov/books/NBK331/.

Humans sweat for a reason, sweating is a physiological process the body uses to cool itself down and maintain its internal temperature, which is called thermoregulation. However, some people have conditions that cause them to sweat too much or not enough due to various physiological issues. It is called hyperhidrosis when a person sweats in excess of what is needed by the body to maintain thermoregulation. This just means that a person is sweating more than is useful for the body. Hyperhidrosis itself is not dangerous, but the underlying issues that cause it can be. There are two main types of hyperhidrosis, primary focal hyperhidrosis and secondary generalized hyperhidrosis. Primary focal hyperhidrosis develops when a person is younger and is not dangerous. However, it does cause both physiological and psychological problems for people that can greatly impact their quality of life. Secondary generalized hyperhidrosis comes on suddenly in adulthood and it can be an indication that someone is unwell.[1]

Secondary generalized hyperhidrosis can indicate a serious underlying health issue and this type of hyperhidrosis needs to be managed by a doctor. Most often, secondary hyperhidrosis is caused by a medication side effect. In this case a patient can choose to stop the medication or use an oral medication to treat hyperhidrosis symptoms if going off of their medicine is not an option. Sometimes however, there is a physiological condition or disease that is causing hyperhidrosis, and it is very important to have it checked out by a doctor. Some conditions that cause secondary hyperhidrosis, like pregnancy, are not medically dire, but some are. Cancers, like lymphoma, and infections, like tuberculosis, can cause excessive sweating so someone who suddenly develops secondary hyperhidrosis needs to seek medical attention. In most instances excessive sweating is caused by a medication or a benign medical condition, but it is important to have it checked out.[1]

Primary focal hyperhidrosis is not physically dangerous, but it can be bad for your health in general, and cause some physical issues if it is not well managed. Excessive sweating can make it difficult to maintain cleanliness, make it more likely for someone to develop a skin infection, and can destroy a person’s clothing. Hyperhidrosis has a larger impact on a person’s quality of life, and this is how it does the most damage. People with hyperhidrosis often struggle with anxiety due to the effect it has on their lives. It can be an extremely embarrassing condition and it can cause people to lose out on experiences they would have otherwise enjoyed. Many people with hyperhidrosis find that it impacts several aspects of their daily lives including intimate relationships, leisure activities, personal hygiene, work, and self-esteem. The effect hyperhidrosis has on a person’s quality of life should not be underestimated. It is just as important to seek treatment for the psychological aspects of the disease as the physical. Luckily, there are several effective treatment options that can help people with hyperhidrosis improve their quality of life. Specifically, botox treatment for axillary hyperhidrosis and a surgical procedure for primary focal hyperhidrosis, called endoscopic thoracic sympathectomy, have shown that they significantly improve patients quality of life. This is especially true when someone suffers from severe hyperhidrosis. There are many other treatments for sweaty hands and feet, and axillary hyperhidrosis, that can also improve patient’s symptoms and their quality of life. There has been some question about whether antiperspirant is safe and, so far, no studies have found negative health outcomes for those who use aluminum based antiperspirant.[1]

Sources

1. Pariser, D. M. (2014). Hyperhidrosis (4th ed., Vol. 32). Philadelphia, PA: Elsevier.

The short answer is “yes” - hyperhidrosis does seem to get better with age. It depends on how you get hyperhidrosis, however. For people who suffer from primary focal hyperhidrosis, the most common type, age does improve symptoms. It has been noted by researchers that hyperhidrosis is significantly less prevalent in elderly populations and this fact has led some to believe that there may be a regression of the disease over time.[1] A study of the prevalence of hyperhidrosis in the US population captures this effect over time. The results from the study show that 2.1% of children age 18 and under have hyperhidrosis, 8.8% of people ages 18 to 39 have it, and only 2.1% of people older than 65 have hyperhidrosis.[2] Trends like this one demonstrate that the disease is most active during the middle years of a person’s life and that symptoms tend to lessen or disappear as people grow older. However, there haven’t been specific studies done on this topic, so researchers speculate that this is the case but they do not know for sure.

Age has an interesting impact on the progression of hyperhidrosis, and even on the type of symptoms people experience. Hyperhidrosis tends to begin between the ages of 14 and 25 for most people with the condition. However, symptoms can begin much earlier as eccrine sweat glands, which become overactive in those with hyperhidrosis, are present and functional at birth. People who get the condition as children, before puberty, are usually affected by excessive sweating of the hands and feet. In fact, 88.9% of children who present with hyperhidrosis experience palmar and plantar sweating. People who get hyperhidrosis after puberty usually experience heavier axillary sweating.[1] It appears that symptoms then tend to be significant throughout middle adulthood, until people grow old. Some have suggested that hyperhidrosis spontaneously regresses at some point in old age.[3] However, it could also be that symptoms gradually reduce over time. More studies need to be done in order to verify what causes the disease to decrease in the elderly.

Hyperhidrosis is a relatively common condition, with an estimated 2.8% of the US population reported to have it. There is also a hereditary component to hyperhidrosis that can affect the age at which a person begins experiencing symptoms. With so many people struggling with this disorder, it is important that research is done to develop future treatments for hyperhidrosis. For the time being, there are several effective treatments that people can use to manage their sweat, and in at least one respect, patients can look forward to the fruits of old age.

Sources

1. Pariser, D. M. (2014). Hyperhidrosis (4th ed., Vol. 32). Philadelphia, PA: Elsevier.
2. Doolittle, James, et al. “Hyperhidrosis: an Update on Prevalence and Severity in the United States.” Archives of Dermatological Research, vol. 308, no. 10, Dec. 2016, pp. 743–749., doi:10.1007/s00403-016-1697-9.
3. Benson, R A, et al. “Diagnosis and Management of Hyperhidrosis.” BMJ : British Medical Journal, vol. 347, 25 Nov. 2013, doi:10.1136/bmj.f6800.

Hyperhidrosis, a disorder characterized by excessive sweating, does have a hereditary component. There are two main types of hyperhidrosis: primary focal hyperhidrosis and secondary generalized hyperhidrosis. Secondary generalized hyperhidrosis is not heritable, but rather it is caused by medication or an underlying physiological condition or disease. However, primary focal hyperhidrosis, is influenced by a person’s genetic makeup. Primary focal hyperhidrosis typically begins between the ages of 14 and 25, but it can begin earlier. People with it experience excessive sweating due to overactive sweat glands on both sides of the body that affects specific areas like the hands, feet, armpits, and face. It is a lifelong condition and it can have a negative impact on a person’s quality of life. Hyperhidrosis is also quite common, as approximately 2.8% (some studies say upwards of 5%) of the US population is estimated to have it.[1]

It is known that 35% to 56% of people with hyperhidrosis have other family members with the same condition. This implies that it is, to an extent, a heritable disease. It is thought that hyperhidrosis is an autosomal dominant condition with variable penetrance. Autosomal dominance means that a person only needs a gene from one parent with the mutation in order to get hyperhidrosis. Variable penetrance means that even if an individual receives the genes that could cause them to have hyperhidrosis, they may or may not get it.[1]

The specific genetics involved in the development of hyperhidrosis are still not well understood. Recently, however, it has been reported that there may be a genetic link for hyperhidrosis on chromosome 14. It is thought that a higher percentage of people may have a familial link to hyperhidrosis than is currently known because people tend to underreport symptoms due to embarassment and stigma. One study done on patients with palmar hyperhidrosis found that 65% of the people who with it had family members with the same condition. It has also been found that the earlier a person get hyperhidrosis the more likely it is to have a genetic component. Most of the current data available regarding the heritability of hyperhidrosis comes from anecdotal evidence and personal communications, which makes it harder to study. Another study that took a history of several families with the condition found that it is most likely autosomal dominant and that it is probably not passed down on the X chromosome. Even in families with hyperhidrosis there were some individuals who didn’t get it, and it is not yet understood why some get it and others don’t.[1,2]

Like many diseases, hyperhidrosis is influenced by both genetics and environment. One study even looked at how genetics and personality traits impacted a person’s likelihood of developing hyperhidrosis. Similarly to other studies, it found that hyperhidrosis had a genetic component and it found that people with the condition tended to be stoical, rigid, orderly, monotonous and did not seem to be extroverted or neurotic. These findings were only from one study and the results could have been caused by chance. Hyperhidrosis and anxiety are known to be closely related, but typically because hyperhidrosis causes people to experience anxiety. The parts of the nervous system that control emotional sweating, or stress sweating, are thought to be overactive in people with hyperhidrosis, and it remains to be seen if this is caused by a genetic abnormality. Correlations like these show how genetics underlie many facets of a person’s life.[3]

Ultimately, hyperhidrosis is a diagnosis that involves both genetics and other factors in a person’s life. Thankfully for those who have it, there are effective treatments and ways to cope with the symptoms. It is also thought that hyperhidrosi may get better with age. People with hyperhidrosis may not have won the genetic lottery, but it could have been a lot worse.

Sources

1. Pariser, D. M. (2014). Hyperhidrosis (4th ed., Vol. 32). Philadelphia, PA: Elsevier.
2. Kaufmann, Horacio, et al. “Primary Hyperhidrosis: Evidence for Autosomal Dominant Inheritance.” Clinical Autonomic Research, vol. 13, no. 2, Apr. 2003, doi:10.1007/s10286-003-0082-x.
3. Karaca, Semsettin, et al. “ Temperament and Character Profile in Patients with Essential Hyperhidrosis.” Dermatology, vol. 214, no. 3, Mar. 2007, pp. 240–245., doi:10.1159/000099589.

Hyperhidrosis is a sweating disorder characterized by sweating that is in excess of what is needed by the body. The reason that humans sweat is to maintain homeostasis of thermoregulation, or to regulate their body temperature. When someone sweats, it releases heat and cools down their core body temperature. People with hyperhidrosis sweat excessively, even when there is no physiological need to. This may sound like an uncommon condition, but it is actually quite prevalent.

It is estimated that approximately 2.8% of the United States population has a form of hyperhidrosis. This number was reached after a survey inquiring about excessive sweating was sent to 150,000 people who live in the US. Other studies have found that up to 5% of the US population have hyperhidrosis, but it is impossible to know the exact number.[2] This is because hyperhidrosis isn’t well known by many doctors, and it is thought that because hyperhidrosis can be an embarrassing condition, it is often underreported. Of those who have hyperhidrosis, it is thought that about 93% have primary focal hyperhidrosis. This is a version of the disease that typically develops during adolescents and affects a person throughout their lifetime. Secondary generalized hyperhidrosis is the second most common type of the disease. It begins suddenly in adulthood, and this type of hyperhidrosis is usually caused by a medication, or a physiological condition or disease. There are other forms of hyperhidrosis, like Hexsel’s hyperhidrosis, Gustatory sweating, localized unilateral hyperhidrosis, and a few others, but they are much more rare.[1]

Both sexes are affected by hyperhidrosis, but it may affect men more prevalently and with more intensity. For example, a study of in Japan found that 16.66% of men had hyperhidrosis while only 10.66% of females had it. A contradictory study in Canada found that women were more likely to report severe hyperhidrosis symptoms, so more studies need to be done in order to know for sure. Men are more likely to have craniofacial sweating and sweating in other areas while women are more likely to have axillary sweating.[1]

People who have primary focal hyperhidrosis most often experience sweating of the face, armpits, hands, and feet. Other locations can be affected, but less commonly so. Roughly 29% of people had an isolated axillary distribution of sweating (affecting the armpits only), while 25% had a pattern of sweating that only affected the hands and the feet. Other patterns of sweating occur, but with less frequency. Only 1.3% of cases involved excessive groin sweating. When a person develops the condition especially early, before puberty, 88.9% of the time it involves palmar or plantar sweating.[1]

It is evident that hyperhidrosis is a common disorder and that it affects people around the World. There are other conditions that cause sweating issues, but they tend to be less common than hyperhidrosis. Luckily, there are several effective treatments for hyperhidrosis that allow people to live more comfortable and productive lives.

Sources

1. Pariser, D. M. (2014). Hyperhidrosis (4th ed., Vol. 32). Philadelphia, PA: Elsevier.
2. Doolittle, James, et al. “Hyperhidrosis: an Update on Prevalence and Severity in the United States.” Archives of Dermatological Research, vol. 308, no. 10, 2016, pp. 743–749., doi:10.1007/s00403-016-1697-9.

Caffeine is massively popular in today’s culture, in fact one study has estimated that 85% of the adults in the United States drink at least one caffeinated beverage a day.

For most people this is not a bad thing, several studies have documented the positive effects of moderate caffeine consumption.

Benefits of caffeine: 

• mental alertness
• concentration
• fatigue reduction
• athletic performance[1]

However, for certain people, caffeine can cause side effects that have a negative influence on their quality of life.

This is especially true for people who suffer from hyperhidrosis, a condition in which a person sweats in excess of what their body needs for thermoregulation.[2]

For people who already struggle with excessive sweating, adding caffeine can cause a bad problem to become worse.

Coffee Causes People to Sweat

Caffeine is a type of mild stimulant.

Even though most people don’t think of it as a drug, it does cause notable psychological and physiological changes in the human body when ingested.

As it is a stimulant, caffeine accelerates the functions of the central nervous system.

While caffeine speeds up several processes within the central nervous system, its specific ability to increase thermogenesis of the body is the primary reason that caffeine causes people to sweat.[3]

Thermoregulation, the ability of the body to regulate its internal temperature, is the reason why humans sweat.

As caffeine accelerates thermogenesis, or causes the body to creates heat, the temperature of the body exceeds its natural set point in the hypothalamus.

The hypothalamus is the part of the brain that regulates physiological processes and it acts as a natural thermostat.

So, when the hypothalamus alerts the body that it is too hot it activates the sympathetic nervous system, which causes physiologic changes like sweating and vasodilation.

Hyperhidrosis, The Nervous System and Coffee

Primary hyperhidrosis is sometimes described as a disease caused by chronic autonomic nervous system dysfunction. The autonomic nervous system is responsible for unconscious bodily functions that keep a person alive, like breathing, temperature regulation and heartbeat.

Specifically, it is thought that the overactive sweat glands and excessive sweating caused by primary focal hyperhidrosis is a result of a hyperactive sympathetic nervous system, a part of the autonomic nervous system that is responsible for the “fight or flight” response.[4]

This is interesting because caffeine consumption also activates the sympathetic nervous system which then causes people to sweat. For someone with hyperhidrosis, drinking caffeine directly activates the part of their brain that is causing their problems in the first place.

Caffeine is also associated with a higher incidence of stress sweating.

This is because it can trigger emotional activity, which by itself can stimulate sweat glands to produce sweat, and affect the neurotransmitters that sweat glands utilize.

Secondary hyperhidrosis is a type of hyperhidrosis that is caused by a specific biological factor.

For example, many common medicines cause hyperhidrosis as a side effect. There are also several conditions and diseases that cause hyperhidrosis as a result of their impact on the body.

Menopause is one of the conditions that can cause secondary hyperhidrosis, and caffeine can actually have an effect on the amount of night sweats and hot flashes that women in menopause experience.

Studies have shown that caffeine intake increases the amount of night sweats and hot flashes menopausal women experience due to the way it influences the nervous system.[5]

The Takeaway

Surveys have shown that the majority of caffeine that adults in the U.S. consume comes from coffee.

This differs from children, who get the most caffeine from carbonated soft drinks.

It has also been found that coffee does not have any substantial health risks when a quantity of 400 mg per day or less is ingested.[1]

That is equivalent to about four cups of coffee.

For someone with hyperhidrosis, it is probably best for them to consume less than that daily maximum.

Caffeine can induce sweating, even when consumed in lower doses, so it is important for individuals with hyperhidrosis to understand how caffeine affects their body specifically.

The goal for a person with hyperhidrosis is the find a balance between drinking the amount of caffeine they want and minimizing the symptoms it causes.

It is not necessary to completely cut out coffee, but in order to manage their sweat, a person with hyperhidrosis should aim to consume around 200 mg per day or less.

Unfortunately for those with hyperhidrosis, like caffeine, alcohol can also cause excessive sweating. So, in order to keep sweating in check, using moderation when consuming tasty beverages is key.

Sources

1. Mitchell, D. C., Knight, C. A., Hockenberry, J., Teplansky, R., & Hartman, T. J. (2014). Beverage caffeine intakes in the U.S. Food and Chemical Toxicology, 63, 136-142. doi:10.1016/j.fct.2013.10.042
2. Pariser, D. M. (2014). Hyperhidrosis (4th ed., Vol. 32). Philadelphia, PA: Elsevier.
3. Tae-Wook, K., Young-Oh, S., Jeong-Beom, L., Young-Ki, M., & Hun-Mo, Y. (2010). Effect of caffeine on the metabolic responses of lipolysis and activated sweat gland density in human during physical activity. Food Science and Biotechnology, 19(4), 1077-1080. doi:10.1007/s10068-010-0151-6
4. Huddle, J. R. (2014). Hyperhidrosis: Causes, Treatment Options and Outcomes. New York, NY: Nova Science.
5. Caffeine intake may worsen menopausal hot flashes, night sweats. (2014, July 14). Science News. Retrieved September 27, 2018.