Although airway blockage was more common in obese subjects, it was not always obvious if this was a true sign of lung illness. For a study, researchers investigated the identification of obesity-induced airway blockage in obese people with healthy lungs by a deliberate increase in end-expiratory lung capacity.

There were 23 participants of normal weight and 66 obese people with healthy lungs in the main research population. To record and quantify breathing loops in terms of specific airway resistance at both typical and purposefully raised end-expiratory lung volumes. A shutter move was used to record the loudness change.

In 11 of the 66 obese patients, the voluntarily increased lung capacity substantially decreased expiratory airway resistance. The decrease was also plainly discernible in the breathing loops and could be measured by a change in total expiratory resistance (sRtEX) of >1 kPa*s. All resistance metrics changed, but sRtEX changed the most. The change in lung capacity had little to no impact on the loops of patients who were of normal weight. Additionally, partial measurements taken of five obese COPD patients indicated a decrease in resistance but no change in airway blockage.

The suggested breathing technique was easy to use and made it possible to identify airway blockage brought on by obesity both quantitatively and qualitatively. It might lessen the possibility of overtreating obese individuals and misdiagnosing them.