After six weeks of wearing the Amazfit Cheetah 2 Pro, I'm convinced Garmin's got something to worry about — just as soon as Amazfit figures out how to make its big running watches more comfortable to wear
…The upgraded optical sensors comprise 5 photodiodes and 2 LEDs, providing continuous 24/7 monitoring for heart rate, blood oxygen saturation, and stress levels. All of these sensors, and more, feed the…