Effects of water immersion on sensitivity and plantar skin properties

Skin, as the largest organ of the human body, has various important functions, like protecting from dehydration or preventing the intrusion of microorganisms. Certain external factors have been shown to negatively influence skin functions. One of those factors is long-term (several hours) exposure to liquids, such as water, leading to skin softening. This study aimed to examine whether detrimental effects, such as skin softening, already exist after short-term water exposure. Furthermore, we investigated whether cutaneous sensation is altered by short-term water exposure. Thirty healthy subjects participated in this study (23.1 ± 2.5yrs, 173.7 ± 8.5 cm, 67.5 ± 9.8 kg). First, vibration perception thresholds (VPTs; 200 Hz), the skin´s elasticity (logarithmic decrement), and the skin´s mechanical deformation resistance properties (durometer readings) were measured at the plantar aspect of the hallux and heel of both feet (pre). Subsequently, one randomly chosen foot was immersed in water (45 min; water temperature adjusted to the foot pre temperatures). The contra-lateral foot remained untreated and out of the water. After the intervention, all three above-mentioned parameters were measured again in the same manner (post). Inferential statistical tests to detect differences regarding elasticity, durometer readings, and VPTs were performed based on logarithmically transformed data (natural logarithm). VPTs did not show significant differences. However, an overall increased elasticity and a softening effect of the skin were evident due to the water exposure at both anatomical locations. This study showed that 45 min of water exposure induces changes in plantar skin properties similar to the long-term effects described in other studies. Most importantly, the short-term water exposure resulted in a softening effect, which may affect skin perfusion in a negative manner. This may facilitate skin irritations and even future ulcer formation. We also showed that changes in mechanical skin properties induced by water exposure did not influence plantar cutaneous sensation. The findings of this study are especially relevant for people with impaired skin recovery mechanisms and highlight the importance of keeping skin dry, particularly in people who are bedridden.