Sweaty palms

How it works

Most sweat cools the body³. A second kind comes from feelings such as stress, anxiety, and pain². This emotional sweating shows most on the palms, soles, face, and armpits, where eccrine sweat glands are densest²³. The sympathetic nervous system, the part that prepares the body for danger, switches it on³.

Your body does not need to be in danger. In one study, people watched a virtual needle go into an avatar’s hand. Their skin conductance, a sign of sweating, rose more than when the hand was only touched. This held even when they saw the hand from outside⁶. In another study, people without a phobia of heights faced a virtual height. They reported no fear, but their heart rate and skin conductance still rose⁵. They faced the height themselves, though. No study was found that measures palm sweat while people watch someone else at a height. One psychologist thinks part of your brain treats the climber’s danger as real, while you know you are safe¹.

One idea about the palms comes from animals. In 1975, researchers blocked paw sweating in four kinds of mammals, including rats and dogs. The paws then gripped a sloped treadmill much less well. A rabbit, with no paw sweat glands, showed no change⁷. The authors concluded that paw sweat helps stop slipping during running or climbing⁷. The study used animals only⁷. For human palms, the psychologist calls it only “one possibility”¹.

Sweat contains salts, so sweaty skin conducts electric current better⁴. This is measured as skin conductance, or the galvanic skin response. The polygraph, often called a lie detector, records it⁴. The signal shows arousal, but not which feeling caused it⁴.

How common it is

No study was found that counts it. Emotional sweating is a normal response². Its size differs from person to person⁴. Some people say they sweat most for climbing videos and less for other scary ones¹. The psychologist writes that “there is no real research into this”¹. The subreddit r/SweatyPalms collects videos that cause the feeling¹⁸.

Try it

1. Watch a short clip of someone climbing a crane or a tall building with no rope.
2. Notice your palms and the soles of your feet.
3. Watch a scary clip with no height in it, such as a horror film jump scare.
4. Compare the two.

Is it a problem?

No. Damp palms under stress are a normal reflex²³. Sweating far more than normal is a separate condition, called hyperhidrosis³. Mention it to a doctor if your hands drip with sweat at rest. Also mention it if sweating gets in the way of daily tasks, or starts for no clear reason.