The advanced activity tracker UP3 is packed with state-of-the-art sensors that give you the full picture of your health. Heart Health Sensor measures resting heart rate - a leading indicator of your overall health and fitness level. Workouts are automatically recognized and logged. You'll gain an in-depth understanding of your sleep. All this is in an impossibly small, water-resistant design with a full week of battery life. So you'll need to recharge before UP3 ever does.