In case anyone doesn’t know, the Apple Health app has sections for asthma, including: Inhaler Usage, Forced Expiratory Volume, Forced Vital Capacity, Peak Expiratory Flow Rate, Oxygen Saturation and Heart Rate.
The world is yours.
EDIT: A couple of comments down, there are instructions on how to find the app and where to find the asthma related sections.
And here’s some general info on using the Apple Health app. imore.com/how-set-and-start...