When I got out of surgery, I was told to breath deep regularly to reduce the risk of pneumonia. Deep breathing improves health. I’ve been doing it since I was 25.

This is the test meter they gave me to test my progress (biofeedback). It measures inhalation. My doctor said I should be good at bong hits. I said that was a possibility.

AirLife-Volumetric-Incentive-Spirometer 55001902

What you want to look for is an AirLife Volumetric Incentive Spirometer, 4000 mL Capacity – 55001902 They cost around $7. My doctor said practice 10 times an hour.