In winter, some people often get a small shock when they touch a door handle. They say, "My body type makes static electricity."

But doctors do not recognize such a body type. Static electricity is made when two things rub together. Some clothes, like a wool sweater under a polyester jacket, make a lot of it. Shoes with rubber soles and dry air also make shocks more common.

Some people call themselves "static-prone," but there is no medical category for this. Static electricity builds up when two materials touch and separate, because electrons move from one to the other. How much charge builds up depends greatly on the combination of materials. In a 2019 study, researchers measured dozens of materials and ranked them by how easily they become positive or negative. Materials far apart on this list tend to create more charge when rubbed together.

For example, wool tends to become positive and polyester negative. Shoes with rubber soles make it hard for electricity to escape into the ground, and dry winter air lets charge build up. So the difference between people mostly comes from clothes, shoes and the environment, which means shocks can be reduced.

Many people who often get static shocks in winter blame a "static-prone constitution," but medicine recognizes no such thing. Static charge comes from triboelectric charging. When two surfaces touch and separate, electrons move from one to the other, leaving one positively charged and the other negatively charged. How much charge builds up depends heavily on which materials meet.

In 2019, researchers measured dozens of materials with a single standardized method and produced a quantitative triboelectric series. Materials far apart on that scale tend to generate more charge. Wool and nylon tend to charge positively, and synthetic fibers such as polyester and acrylic negatively, so a wool sweater under a polyester down jacket is a likely recipe for shocks. Humidity matters too, as engineering research from the 1960s has shown.

Moisture lets charge leak away gradually, while dry winter air lets it accumulate. The body itself may play a part, since dry skin may hold charge more easily and skin dryness varies between people, though direct comparisons in humans are scarce. Shoes matter more clearly. Rubber or plastic soles hinder charge from escaping to the ground, and the amount the body stores varies with the combination of footwear and flooring.