Sun and ultraviolet light exposure has both short term and long term effects on skin. While the short term effects, such as sunburn, are understood, chronic long-term sun exposure can cause changes to the skin that are not well characterized. One particular alteration may be how the skin consumes oxygen, a change that may be linked to biochemical alterations that have been observed in past studies. Measuring skin oxygen consumption has traditionally been difficult as the tools available have not been easy to incorporate into clinical studies. In this study, we overcome this barrier through the use of a new non-invasive oxygen-sensing device that can rapidly measure skin oxygenation properties such as oxygen consumption. This observational study will measure the oxygenation properties of both chronically sun exposed and less sun exposed skin in the predefined groups of both young and older men and women.