RACISM IS EVERYWHERE: Black smartwatch users may see less accurate heart rate data. “The problem stems from the basic technology used in most wearables. It measures heart rate by analyzing blood volume changes in the blood vessels, via light that passes through the skin. That light is usually green light. . . . Green light has a shorter wavelength, Shah explained, and it’s more readily absorbed by melanin, the pigment in skin. The upshot: Darker skin blocks more green light, which can dampen the accuracy of the devices’ measurements. Shah agreed the discrepancies are a concern, in part because the devices are being used in employee wellness programs and the like. Many companies incentivize employees’ use of fitness trackers with financial perks, like extra vacation days or even lower health insurance premiums.”