Here is an affordable smartwatch that combines with your iOS and Android device to monitor your heart rate and track your daily activity. The ZeRound3 Lite Smartwatch has a TFT color screen to show your social media notifications, calendar events an reminders, and other info. You can also use it as a remote control for photos and music.
This watch lasts up to 3 days on a single charge. You can find out more about it here.