BreathScore

BreathScore measures your lung capacity, also called 'forced vital capacity' or 'FVC' and your speed of exhalation, called 'Forced Expiratory Volume in 1 second', or 'FEV1'.

The FVC is:

• Usually 3-6 liters, varying with age, gender and height
• Reduced in certain diseases that restrict lung expansion
• Increased in athletes and very fit people
• Correlated with disability in chronic lung disease

FEV1 is the volume of air expelled in the first second of maximal forced expiration from a position of full inspiration. In normal people the fraction of the FVC which can be expelled in one second is:

• 70% in males
• 75% in females

FEV1:

• Is reduced in obstructive lung disease, such as emphysema
• Correlates with maximal exercise capacity

FEV1 is by far the most frequently used index for assessing airway obstruction, bronchoconstriction or bronchodilation.

The FEV1/FVC ratio is the ratio of the forced expiratory volume in the first one second to the forced vital capacity of the lungs. The normal value for this ratio is above 0.70, though this is age dependent varying between 0.70 and 0.90. Values less than 0.70 are suggestive of airflow limitation with an obstructive pattern, such as in emphysema or asthma. Restrictive lung diseases often produce a FEV1/FVC ratio which is greater than 0.85.

FEF 25-75 or 'mid-expiratory flow rate' is the flow rate over the middle portion of the forced exhalation and represents airway obstruction involving primarily smaller airways in the lung. It is a more sensitive indicator of the early stages of emphysema, or mild asthma.

In your report, the last column is called 'percent of predicted'. If this is below 100%, your results are worse than predicted, if it is over 100%, your results are better than predicted.