Yes, it can monitor your health and fitness. You should choose one that has a pedometer to count your steps. An accelerometer is helpful in determining acceleration. Acceleration can be used to detect when you fall. A heart rate sensor can be used to monitor your heart beats. Some will report the amount of calories you consume and even display a report of your health at day’s end.
For deeper integration with your Android phone, you can give Google's Wear OS platform a try with Fossil's $275 Q Control touchscreen smartwatch. It lacks GPS and support for NFC payments, which is why the Gear Sport is a better fitness-focused smartwatch for Android users, but Fossil's Google Assistant integration and stylish design make it a solid contender. However, smartwatches with Qualcomm's new Snapdragon Wear 3100 processor start shipping in October, so you may want to hold off until we put them to the test.