Why Water Turns You Into a Prune

Do you love taking long, hot showers or soaking in the tub? Or perhaps you swim like a fish and hit the pool every day?

You’ve surely noticed the curious effect of water on your skin.

“After just a few minutes in wet conditions, the palms of your hands, the soles of your feet and, in particular, your fingertips, will transform from smooth to wrinkly,” says dermatologist Alok Vij, MD.

What gives — shouldn’t exposure to water plump your skin up like a plum, rather than wrinkling it like a prune?

A matter of survival

“This is a fascinating question,” says Dr. Vij. “That ‘pruning’ is more than just passive absorption of water into the protein-rich outer layer of your skin.

“It is an active, adaptive process controlled by your sympathetic nervous system.”

The sympathetic nervous system is part of a larger system in charge of unconscious body processes like digestion and breathing.

It’s mainly responsible for the “fight or flight response” that helped us run from a saber tooth tiger in prehistoric times.

But it also appears to help us grip objects better in wet conditions — allowing us to grab the slippery, wriggling fish we needed for survival back in the day.

“The grooves appearing in your skin act like tire treads,” explains Dr. Vij. “They allow water to slide out from between the surface of your fingertips and the surface of objects you’re trying to grasp — like that bar of soap you just dropped.” 

Skin-friendly showers and baths

While pruning is harmless, it’s best not to overstay your skin’s welcome in a shower or tub. 

Bathe in warm, not hot, water to avoid removing the natural oils from your skin.

As soon as you get out, towel-dry briefly. Then quickly apply moisturizer to add moisture back into your skin’s outer layer.

Protecting your skin in the pool

“Frequent swimmers encounter bigger problems than wrinkling of their fingers,” notes Dr. Vij.

Constant exposure to water, chlorine and other chemicals can cause dry skin, eczema or folliculitis.

To avoid the skin irritation, itching, inflammation or infection that result, he advises you to:

1. Take a short shower, using warm water and mild soap, soon after you get out of the pool.
2. Apply a moisturizer after you exit the shower.
3. Always wash swimsuits and dry them thoroughly before wearing again.
4. Apply a water-resistant or waterproof sunscreen half an hour before swimming outdoors, and each time after you leave the pool and towel off.

Pruning aside, these tips will help you enjoy swimming’s many benefits without consequences for your skin.