Why am I sweating so much?

Excessive Sweating image

The 101 on hyperhidrosis


If you are self-conscious about how much you sweat, you could be suffering from a condition called hyperhidrosis. Many people who live with it do not even know that it is a medical phenomenon; they just think it is an unfortunate and frequent occurrence that they need to work around. While hyperhidrosis is not a life-threatening disease, anyone who has it can attest to the fact it is very inconvenient, embarrassing, and can be a great impact on daily school, work and social activities. 


So if you’re one of them, you’ll be pleased to know that hyperhidrosis has long been given attention by the medical community. There are options available to help better manage, or, in some cases, completely eliminate this condition.


But before you go in search of a cure, it’s important to get a better understanding of hyperhidrosis.

What causes us to sweat?

To understand the causes of excessive sweating, it is first important to consider what causes normal sweating. And at the centre of that conversation is the hypothalamus.


The hypothalamus wants to keep our bodies at a constant temperature of 37 degrees Celsius. When the body appears to be getting a little too hot for comfort, temperature sensors in the skin and internal organs send messages to the hypothalamus to do something about it. Among the many ways to cool the body down, releasing sweat through the sweat glands is one of the most effective responses. This is called “thermoregulatory sweat”.


However, it’s not just increased heat or exertion that causes us to sweat. Strong emotions and stress can cause us to break out in what is commonly known as “cold sweat”. Whereas thermoregulatory sweat is usually excreted throughout the body, emotional sweat is typically concentrated in the armpits, face, palms, and feet. 


It is important to consider that these two general types of sweating are interrelated. It is likely that one process influences the other.

What causes excessive sweating?

There are two general kinds of hyperhidrosis. Usually, it is easy to differentiate the two based on onset of the disease, family history, and symmetry of affected areas, but in some cases, further tests may need to be done to confirm the diagnosis.


Primary hyperhidrosis

Primary hyperhidrosis can run in families. Though the exact gene that controls this has not been identified, it appears to be autosomally inherited with incomplete penetrance.  This is a fancy way of saying that it can be passed on to both males and females of the family, and can manifest with different severity and presentation among family members. So if you have primary hyperhidrosis, there’s a good chance you’re not the only sweaty one in the family.


This condition usually appears in childhood or puberty, and can continue into adulthood. There are some who report a period of quiescence or remission, but for some, it’s something they live with for most of their adult lives.


Primary hyperhidrosis can be focal (meaning only in one area such as the armpits) or generalised (head and trunk). A hallmark of focal primary hyperhidrosis is that it presents symmetrically.  So in these cases, if the right armpit sweats a lot, you can expect the left to do the same. You can have it in one or more areas of the body. For some, they may even present with both focal and generalised primary hyperhidrosis.

Secondary hyperhidrosis

Secondary hyperhidrosis can be caused by hormonal imbalances, neurological or endocrine diseases, or certain types of drugs.  Pregnancy and menopause have been associated with periods of excessive sweating that may extend for months up to years. Some people develop hyperhidrosis as a side effect of conditions that affect the brain, spine, and peripheral nerves, while others start to notice increased perspiration after taking cholinergic drugs, antidepressants, and opioid painkillers.


Sudden onset of increased volume and frequency of sweating in people who have no prior history of sweatiness is a potential sign of secondary hyperhidrosis. 


Like primary hyperhidrosis, secondary hyperhidrosis can be both focal and generalised. The difference is that when it does manifest focally, it tends to occur on one side. This is usually because of a compensatory mechanism, ie, it is possible that the nerves supplying the right side of the body have been damaged and no longer produce sweat, so the nerves on the left side work extra hard to make up for it. Generalised secondary hyperhidrosis can be difficult to differentiate from generalised primary hyperhidrosis, but that’s what a visit to the dermatologist is for! 


For some, it is easy to identify the trigger. But for others, it may not be so clear-cut. Usually, secondary hyperhidrosis is accompanied by other red flags that something is wrong in the endocrine or nervous system. If there are no other signs, doctors will usually prescribe a battery of diagnostic tests in an attempt to find out what’s causing it.


Purpose of this information

The information presented on this website and in this article is for general information and example purposes only, does not contain health advice specific for users and must not be relied on for that purpose.  Please see your GP, dermatologist or other health care professional for specific advice.





Rystedt A, Brismar K, Aquilonius SM, Naver H, Swartling C. (2016). Hyperhidrosis – an unknown widespread “silent” disorder. Journal of Neurology and Neuromedicine, 1(4): 25-33.


Schlereth, Tanja & Dieterich, Marianne & Birklein, Frank. (2009). Hyperhidrosis-Causes and Treatment of Enhanced Sweating. Deutsches Ärzteblatt international. 106. 32-7. 10.3238/arztebl.2009.0032. 




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