Current Data on Effects of Long-Term Missions on the International Space Station on Skin Physiological Parameters

<b><i>Background:</i></b> Skin reaction to spaceflight has not really been studied yet, although the skin has a very important barrier function to protect the body and can contribute to a more general understanding of physiology. It is proposed here to make a more thorough investigation of the skin during long-term spaceflight, using noninvasive techniques. <b><i>Aims:</i></b> The aim of the present Skin-B study is to investigate the kinetics and range of possible skin modifications during long-duration spaceflights and their recovery. <b><i>Methods:</i></b> In order to investigate the effect on skin physiological parameters during spaceflight, measurements were carried out on 6 astronauts with respect to skin hydration, transepidermal water loss/barrier function, and surface evaluation of the living skin in orbit. Additional measured parameters on the ground were skin elasticity, skin density and thickness, as well as microcirculation. <b><i>Results:</i></b> Data from the Skin-B subjects (<i>n</i> = 6) contradict the results obtained in the previous pilot study SkinCare (<i>n</i> = 1 subject). In the present study, no deterioration of the skin was found but rather an improvement in skin hydration and skin barrier function, and no changes or improvement in the appearance of the skin surface. Furthermore, the skin density and skin thickness as well as skin elasticity values were unchanged from pre-flight values. <b><i>Conclusion:</i></b> In conclusion, we found that spaceflight under present conditions has no negative impact on skin physiological parameters.