"A shower presents additional difficulties - soap lowers surface tension, and warm water has lower surface tension as well. Add to the fact that a shower can sometimes have powerful jets."
"Here's why you shouldn't wear any watch in the shower. Inside a water resistant watch is air. Air contains water vapor. If you sit in a hot tub, or sauna, or take a long hot shower you heat up the air inside the watch. Like that shiny sapphire crystal on your watch? Sapphire is a fine conductor of temperature. Ever leave a movie theater on a muggy August day, you walk outside and your glasses fog up? Same thing can happen to your watch when you exit the shower/sauna/hot tub and go into a cold room. I get clients saying 'water got in my watch from the shower when in reality it's condensation on the underside of the crystal."
Our recommendation to this question is no. There are a few things to keep in mind:
1. Mechanical watches are water resistant, and not water proof. This means that they have been tested to their rated depth using water testing machines, but they are not guaranteed to never leak.
2. Showering presents challenges to mechanical watches other than just water. These include the effects of soap, shampoo or other cleaning agents which may over time weaken the effect of the seals.
3. The strap may be damaged by exposure to water.
4. The spray from a shower head if aimed in certain directions on a mechanical watch can simulate water depths beyond the rating of the watch.