Bored With Your Fitbit? These Cancer Researchers Aren't

If you're trying to get in shape and you want a tiny, wrist-bound computer to help you do it, you have more options than ever before. Fitness trackers come in all shapes, colors, and price tags, with newfangled sensors and features to stand out to customers. But for doctors and scientists studying how exercise can help people deal with disease, the landscape is much simpler. Like most fitness trackers, Fitbit's devices are far from perfect. They can count steps pretty well and give a good idea of activity levels day to day.