A recent study showed, that the condition in which you sleep may contribute to the wrinkles on your face. When you lay your face on a pillow, you may be placing it in a position that affects your skin, therefore it causes the skin to stretch, shear, and compression forces on your skin. Lateral sleeping (on your side) and the prone (face down in the pillow) are the positions that are considered to cause wrinkles while you sleep. As we get older we move less while we sleep, this results in a longer amount of time in one position, therein a longer duration of time a wrinkle producing force is being applied to an area of skin.

{The location and orientation of sleep wrinkles are often different than wrinkles caused by facial expression, ( Please see the example below, Common sleep wrinkle locations and orientation marked in black]