Is it possible for a device to measure how much air we breathe in and out over the entire day and at what rate? I think if we have access to this data we can compare it across people.
What you are looking for is a spirometer. There are different types of spirometers serving different purposes like the Incentive spirometer and the peak flow meter. I would suggest that you go through the wikipedia page on it to get more info.
- Pulmonary Gas Exchange (VO2, VCO2)
- Breath by Breath Technology
- Telemetry Data Transmission up to 1000m
- Indirect Calorimetry
- Integrated GPS System
- Integrated Oxygen Saturation (SpO2)
- Integrated 12-lead Stress Testing ECG