Hyperhidrosis – What Causes Excessive Sweating?

Welcome to the Hyperhidrosis-Center – your online guide to hyperhidrosis and overcoming excessive sweating! We’re glad you made it here and hope you find the all the information you need to tackle your hyperhidrosis problem.

We all sweat, but many of us never consider what sweat actually is and why we sweat in the first place. It is not until sweating becomes excessive (hyperhidrosis) that we actually start to pay attention to our sweating. Under normal circumstances, we sweat primarily in response to an increase in our body temperature.


Typically our body temperature is approximately 37ºC and when the temperature rises higher than this level, our bodies must do something to bring the temperature back down to normal. This is achieved through sweating – a bodily function under control of the hypothalamus in the brain and the mechanism by which we lower our temperature naturally.

This is a response that is out of our control and is a protective mechanism; an elevated body temperature can be dangerous to our health. The elevated temperature can occur for a number of reasons such as the weather, environment and physical activity. The hypothalamus stimulates the nerves that control the sweat glands and sweat is released, lowering our temperature back to a safe level. This occurs as water (one of the main components of sweat) is a natural coolant and as the sweat evaporates off the skin, it draws heat to the surface and cools us down.

Different Types Of Sweat Glands

Humans have anywhere between 2-4 millions sweat glands and these can be found over the entire surface of the skin of the human body, except for a few limited locations. We have two primary types of sweat glands: Apocrine and Eccrine and this is where the secretion of sweat occurs.

Eccrine sweat glands can be found all over the body, although in some areas there will be a higher concentration of these sweat glands than others. The palms of the hands, soles of the feet and the scalp of the head are where the concentration of these glands is at its highest. Sweat is released directly on to the skin surface from these glands (as they are not associated with hair follicles) with the primary function of thermoregulation – the cooling effect discussed previously. This is known as normal sweating or sensible perspiration. The sweat secreted from these glands is a watery, clear liquid.

The other type of gland is the Apocrine sweat gland and these are not nearly as widespread as eccrine sweat glands. The apocrine glands are associated with hair follicles and are mainly found in the armpit and genital regions. These glands are much larger than eccrine glands and produce a cloudy appearing liquid that interacts with bacteria on the skin and forms the class body odor smell of humans. The sweat produced here has no thermoregulation influence and is thought to contain pheromones – chemical stimulants that are used to attract a member of the opposite sex.

Too Much Sweat?

Now you know that sweating is a temperature regulating response (also known as thermoregulation) but how much do we need to sweat to achieve this and why do some people sweat more than others? We all sweat as a response to a rise in body temperature (heat) and also in cases of emotional disturbance e.g. when we are stressed or anxious. Some people sweat more than others, and typically men will sweat more than women. In some circumstances, people sweat in the absence of any of heat, emotional disturbance and for the majority of the day. For people that suffer from excessive sweating it will feel like they sweat for no apparent reason and find it very difficult to stop sweating. This type of sweating is known as hyperhidrosis.

Hyperhidrosis can be divided into two main categories – general or local hyperhidrosis. General hyperhidrosis is characterized by excessive sweating throughout the whole (or the vast majority) of the body where as local hyperhidrosis will usually be limited to only one of two (sometimes more) regions of the body. Most commonly, it is the armpits, groin, hands, face/head or feet that will be affected by localized hyperhidrosis. These areas have a higher concentration of eccrine sweat glands than other areas of the body and this may explain why local hyperhidrosis tends to occur here. Hyperhidrosis has a different name depending on which body part is affected, and these types are detailed below:

In addition to this, hyperhidrosis can be further classified as primary or secondary hyperhidrosis. If hyperhidrosis is present in the absence of any other medical disease or condition (including some medications) that may otherwise cause excessive sweating then this is termed primary hyperhidrosis. In other words, there is no clear or obvious reason why someone would be sweating excessively. If however the excessive sweating is associated with a different medical condition, disease or as a side effect of certain medications then this is termed secondary hyperhidrosis. In other words, there is a clear and obvious reason why someone is sweating excessively.

Hyperhidrosis Causes

Primary Hyperhidrosis Causes: It is not known for certain what the precise causes of hyperhidrosis are, unfortunately. Nonetheless, the most widely accepted cause of hyperhidrosis is over-activity of the sympathetic nervous system. This is the section of the nervous system that controls the sweat glands, and if this part of the nervous system excessively stimulates the sweat glands through over-activity then an excessive amount of sweat will be produced. In most cases this is believed to be genetic in origin and may run in families. If the over-stimulation is localized to a certain area of the body rather than the entire body then excessive sweating will only be seen there.

Secondary Hyperhidrosis Causes: this type of hyperhidrosis will be seen in the presence of a medical condition that triggers the excessive sweating. Often this will occur in cases of Diabetes, Cancer, Obesity, Uterine Fibroids, Alcoholism, Drug Abuse Withdrawl or Hyperthyroidism. Various prescription drugs have also been linked with secondary hyperhidrosis; most commonly anti-depressent or anti-cancer preparations.

It is also worth re-visting the connection between emotional disturbance and excessive sweating. People that are liable to become stressed, anxious or nervous easily may sweat more than the average person. This is slightly different to the types of hyperhidrosis mentioned above and is an example of a psychological connection with hyperhidrosis.

Hyperhidrosis Symptoms

First and foremost, excessive sweating is visible on the skin and sweat stains are visible on clothing. In some cases there can also be an unpleasant smell that is associated with this, especially with infrequent showering and changing of clothes.

Hyperhidrosis can be an extremely difficult and embarassing conditon to live with any may result in anxiety in social situations and intimate situations. It can make seemingly trivial tasks like opening a door or writing become incredibly tricky and impact the quality of life. It can also make sleeping difficult for those that suffer from night sweats. Now that we have covered the background of sweating and the basics of hyperhidrosis you can navigate to the other pages of the website using the ‘pages’ menu on the left hand side to find out more information about your specific problems and learn how to overcome sweating for good! You can also contact us to find out more about our website or ask us any questions about your sweating problems.