Arterial stiffness will be determined using a Sphygmocor pulse wave applanation tonomoter (Atcor Medical). This device measures arterial pulse waves non-invasively through the skin at the wrist. We will use this same device to analyze the shape of the pulse wave, which will give us information about reflected pulse waves (and thus the stiffness of the arterial tree). The measure of arterial stiffness is non-invasive and pain-free and is taken using a pen-like tool pressed against the participant's skin to detect his or her pulse.