Effects of extreme environmental conditions on the skin barrier: a pilot study from the "Under The Pole" project with spectral and biometric measurements.

INTRODUCTION

Under The Pole is an ambitious underwater exploration program in extreme environments, particularly in deep and polar regions. Diving in the cold and saline waters of the Arctic exposes the skin to intense thermal and osmotic stress, potentially altering its barrier function. This study aimed to evaluate both the acute and long-term effects of repeated cold-water diving on skin hydration and barrier integrity during a two-month Arctic expedition.

METHODS

Seven healthy Caucasian male participants without facial skin lesions were monitored throughout the expedition. Skin appearance, hydration and transepidermal water loss (TEWL) were measured. Stratum corneum (SC) samples were collected by tape stripping and analyzed using Raman spectroscopy and Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy to assess molecular changes in lipids and proteins.

RESULTS

The findings reveal a dynamic, multiphasic adaptation process of the skin barrier under extreme polar conditions: (i) Immediate phase (hours): Acute hydration increase and transient barrier disruption due to immersion and temperature shock. (ii) Short-term phase (days): Adaptive homeostatic response, characterized by decreased water loss and lipid disorganization and protein structural rearrangement within the SC. (iii) Long-term phase (weeks): Gradual barrier fatigue with partial recovery of lipid order and protein structure, but persistent microstructural alterations evidenced by reduced hydration and elevated TEWL.

CONCLUSION

This study provides in situ evidence of dynamic skin adaptation to extreme Arctic conditions. Initial barrier disruption was followed by molecular reorganization and partial recovery, yet prolonged exposure led to cumulative dehydration and barrier fatigue. These insights improve understanding of cutaneous resilience and support the design of protective skincare strategies for extreme environments.