Understanding Why Fingers Prune in Water: The Science Behind Wrinkled Skin

As swimming and water-based activities become more popular, many people notice their fingers become wrinkled or 'pruney' after spending time submerged. While this common phenomenon has often been thought to involve skin swelling, recent research sheds new light on the true cause. Scientists from Binghamton University, State University of New York, have discovered that these wrinkles result from blood vessel constriction under the skin, rather than from the skin absorbing water and expanding.

The research was initiated after a follow-up question from a student, prompting researchers to investigate whether wrinkling occurs in consistent patterns. Led by biomedical engineer Guy German, the team conducted experiments in which participants soaked their fingers in water for 30 minutes, photographed the resulting wrinkles, and repeated this procedure after 24 hours. Remarkably, the pattern of wrinkles—comprising raised loops and ridges—remained consistent over time.

German explains that blood vessels do not change position significantly; they may shift slightly, but generally stay static relative to each other. This stability means that the wrinkles formed are also consistent in pattern, which was confirmed by their findings. Additionally, the team observed that individuals with median nerve damage, which affects nerve signaling to blood vessels, do not develop pruney fingers, further supporting the vascular constriction hypothesis.

Understanding the mechanisms behind skin wrinkling has potential applications beyond simple curiosity. For instance, it could aid forensic investigations by improving fingerprinting techniques or identifying individuals after water exposure. This intersection of biology and forensics highlights the importance of such research, with German noting his fascination with skin science and its broad implications.

Ultimately, this research redefines our understanding of wrinkled fingers, revealing a fascinating interplay of blood vessel activity beneath our skin during water exposure. Ongoing studies aim to further explore skin responses and their practical applications in medical and forensic fields.