Oxygen absorption by skin exposed to oxygen supersaturated water

Abstract

The present study tests the hypothesis that skin on the plantar surface of the foot absorbs oxygen (O2) when immersed in water that has a high dissolved O2 content. Healthy male and female subjects (24.2 ± 1.4 years) soaked each foot in tap water (1.7 ± 0.1 mg O2·L–1; 30.7 ± 0.3 °C) or O2-infused water (50.2 ± 1.7 mg O2·L–1; 32.1 ± 0.5 °C) for up to 30 min in 50 different experiments. Transcutaneous oximetry and near infrared spectroscopy were used to evaluate changes in skin PO2, oxygenated haemoglobin, and cytochrome oxidase aa3 that resulted from treatment. Compared with the tap water condition, tissue oxygenation index was 3.5% ± 1.3% higher in feet treated for 30 min with O2-infused water. This effect persisted after treatment, as skin PO2 was higher in feet treated with O2-infused water at 2 min (237 ± 9 vs. 112 ± 5 mm HG) and 15 min (131 ± 1 vs. 87 ± 4 mm HG) post-treatment. When blood flow to the foot was occluded for 5 min, feet resting in O2-infused water maintained a 3-fold higher O2 consumption rate than feet treated with tap water (9.1 ± 1.4 vs. 3.0 ± 1.0 µL·100 g–1·min–1). We estimate that skin absorbs 4.5 mL of O2·m–2·min–1 from O2-infused water. Thus, skin absorbs appreciable amounts of O2 from O2-infused water. This finding may prove useful and assist development of treatments targeting skin diseases with ischemic origin.