Smartwatches sync with your computer or smartphone to record and keep track of your daily fitness data. Each smartwatch is different, but most monitors steps, calories, sleep and heart rate. They also provide alerts like incoming calls, texts and emails. You can also get a smartwatch that will try to motivate you to move with rewards and challenges. Smartwatches use an accelerometer to measure steps and other movements. Some use a gyroscope and magnetometer to track activities like running or swimming. Others may also use GPS to pinpoint your location and a barometer to determine your altitude to calculate how many flights of stairs you climb.