It’s a Myth That Sweating Is a Sign of High Blood Pressure

It's a misconception that hypertension (also known as high blood pressure) can cause you to sweat. In fact, in extreme cases, excessive sweating can mean very low blood pressure. Excessive sweating and not sweating enough can also signal other health problems.

​Read more:​ 6 Things Your Sweat Can Tell You About Your Health

Perspiration, more commonly referred to as sweat, is a salty clear liquid generated by your skin glands, notes the U.S. National Library of Medicine.

Essentially, you sweat to cool yourself down, and it's a normal bodily reaction. When you're hot or engaging in strenuous activity, sweat will show up primarily under your arms, on your feet and on your palms.

Even though sweat can sometimes smell when skin bacteria comes into contact with moisture, the truth is that real problems with sweating arise only when you don't sweat enough or when you sweat too much.

​Read more:​ Lack of Sweating During Exercise

According to the Mayo Clinic, the inability to sweat sufficiently is a medical condition known as anhidrosis (which can also be called hypohidrosis).

People who can't sweat normally, whether they can't sweat over most of their body or only across certain parts of the body, can get overheated to the point of developing cramping, heat exhaustion or even heatstroke, which can be fatal. This condition is sometimes inherited, but in other cases, it may be the result of skin trauma, certain drugs or specific conditions.

On the other hand, Mayo Clinic experts point out that some people have an excessive sweating condition called hyperhidrosis. In that situation, the individual may sweat in the absence of extreme heat or vigorous physical activity, and the amount of sweat may be far more than normal, causing clothes to literally drip on contact.

Experts at the American Academy of Dermatology (AAD) estimate that perhaps as much as 3 percent of Americans have hyperhidrosis, and it's not always clear what causes it. However, the AAD says that most people with this condition either have a family member who also has it, they have an underlying medical condition — such as gout or diabetes — that increases the risk or they're taking a medication or supplement that triggers the situation.

Despite popular belief, high blood pressure does not cause sweating. According to the American Heart Association (AHA), sweating is among a variety of symptom "myths" (alongside nervousness, difficulty sleeping and facial flushing) that have sometimes been falsely thought of as signs of high blood pressure.

"Individuals with high blood pressure usually do not have any symptoms," says Gregg Fonarow, MD, director of the Ahmanson-UCLA Cardiomyopathy Center. Sweating, he says, "is not a usual sign of high blood pressure."

That said, in certain situations, sweating could actually be a sign of a different heart health concern: low blood pressure.

According to the National Heart, Lung, and Blood Institute (NHLBI), a healthy blood pressure should be less than 120/80 millimeters of mercury. However, when it goes too low — less than 90/60 — low blood pressure is at hand. While low blood pressure may be symptomless as well, people who struggle with it may at times feel weak, confused, tired or lightheaded.

If blood pressure falls very, very low, it likely means a dangerous slowdown in the normal flow of oxygen and nutrients throughout the body. In extreme cases, that could trigger clinical shock, one of the signs for which is cold and sweaty skin (alongside a weak or rapid pulse, a blue skin tone and rapid breathing).

The NHLBI urges anyone who might be experiencing this type of low-blood-pressure-triggered sweating to call 911 or seek immediate attention at an emergency room.

​Read more:​ The 6 Big Health Risks of Low Blood Pressure — and What to Do About It