Why do your fingers prune up in bath water, and not in a pool in Cancun?

Question

I just realized how I stayed in a pool in Cancun the whole day for days and my fingers looked fine, but stay in a bath for too long and my fingers are totally pruned! What is the science behind this...just really curious!

Answer 1

It's probably because your pores absorb water.

Considering I went to Puerta Viarta and nearly left there with my face all scared up (this be foreshadowing), I would say that Cancun is warmer. Considering how warm it would be, you were probably just sweating the water off. Unlike in a bath where you aren't sitting under the sun.

So, you were just sweating. The warm weather made you start sweating while you were in the pool, which stopped you from getting prune fingers. But, when in the bathtub you would not be under a really warm sun in substantially warm water.

Edit:I didn't get scared thankfully, I was just peeling REALLY badly and nearly made myself have scars picking it off.

Answer 2

The skin is a semipermeable membrane, water will pass through a semipermeable membrane in order to dilute a more concentrate solution on the opposite side by osmosis.

As skin tissue contains higher levels of things such as salt than plain bath water it is more concentrated, the water from the bath will slowly pass through the skin in an attempt to ‘dilute’ this higher concentrate solution. Consequently, ‘ridges’ appear on our fingers as the skin takes on this extra water.

Water in a pool is usually much closer to concentrations in the skin tissue or more concentrated. The osmotic process means that usually almost no water passes into the skin or water is passing out of the skin. So no pruning.