Underwear is designed to stay close to the body, which means certain areas experience continuous contact and pressure throughout the day. Elastic around the waist, hips, thighs, or under the breasts can press into the skin.
When clothing remains in the same position for several hours, it may
temporarily compress the upper layers of the skin. After the garment is removed, a visible line or indentation may remain.
This is similar to the marks sometimes left by socks, watchbands, sports clothing, or other fitted garments.
The appearance of the mark can depend on several factors, including the tightness of the garment, the material, how long it was worn, body movement, and individual skin sensitivity.
Tight Elastic Can Create Pressure Lines
One of the most common explanations is simply that the elastic is too tight.
