Health app, part of iOS 8, provides a central place for all your health, fitness, nutrition, sleep, medical, and related information. A medical ID feature will allow first responders to find out vital information in case of emergency, and thanks to the HealthKit framework for developers and accessory vendors, App Store apps and peripherals will be able to share their data as well.
Broad categories in Health include Diagnostics, Fitness, Lab Results, Me, Medication, Nutrition, Sleep, and Vital Signs. Data is presented in both graphs and separate sub-catagories. Graphs can be added to a dashboard view for easy monitoring when the Health app is launched.
The information in Health can be just for you, or it can be sent to other apps, or it can be shared with a doctor or other healthcare professionals.