The perimeter will be bonded at the very least, so about 10% attached and 90% `free`lace. Sweat will be trapped under that [bond]...shower-water will not get at it. The acids in sweat will gradually damage any base so my advice would be if you intend doing activities during which you will sweat heavily, you might want to do a more frequent clean-up just to prolong your system`s life and avoid scalp-irritation which can ensue from moisture/sweat being trapped under your bonded area.....if you notice any redness/itching there, just leave the system off overnight and apply a thin layer of sudocreme --great for any type of skin irritation and has a drying-effect... Paul.