A fitness tracker is an application or device used in tracking and monitoring fitness goals. It measures metrics such as distance run or walked, rate of heartbeat, calories consumed and sometimes even the quality of your sleep.Most of these tracking devices are wirelessly synchronized to a smartphone or computer for the purposes of regular data tracking and reporting. In this book we’ll be looking at a ton of different aspects revolving around fitness tracking.There aren’t many books dedicated specifically to life logging which is a shame because there’s just so much to it.