How a sweatband holds liquid
Terrycloth is covered in tiny loops of yarn, creating many spaces where liquid can collect. Sweat can also cling to the fibers, so a dry band draws moisture into itself rather than letting it immediately run over the skin. This movement into narrow spaces is called capillary action—the same basic effect that helps a paper towel soak up a spill.
What changes when the cloth is saturated
A band has limited room to store liquid. As sweat fills the spaces between its fibers, less remains available to take up more. Sweat may still spread through the cloth, but if it arrives faster than it can be absorbed or evaporate, excess liquid runs off. Gravity pulls it downward, while the band’s edges can guide it around the head and toward the back of the neck.
So a sweatband does not stop sweat production; it temporarily stores some of the moisture. Once its fibers and spaces are full, the same band can become a route for sweat to travel rather than a place for it to stay.
