Lung Capacity & VO2 Max Estimator

Lung Function Guide

What FVC and FEV1 Mean

FVC (Forced Vital Capacity) is the total volume of air you can forcibly exhale after a full breath — a measure of total lung capacity. FEV1 (Forced Expiratory Volume in 1 second) is how much air you can exhale in the first second of that forced breath — a measure of airflow. The FEV1/FVC ratio distinguishes between obstructive (low ratio, e.g. COPD, asthma) and restrictive (low FVC with normal or high ratio, e.g. fibrosis, obesity) lung disease. A ratio below 70% is the threshold for an obstruct

Predicted Normal Values

Predicted lung function is calculated from population reference equations based on age, height, and sex. The most widely used in the UK are the European Respiratory Society (ERS/ECSC) or Global Lung Function Initiative (GLI) equations. Results are expressed as % predicted — values between 80–120% of predicted are generally considered normal. Below 80% may indicate impairment. Lung function peaks in the mid-20s for most people and declines at approximately 1% per year thereafter — smoking acceler

VO2 Max and Cardiorespiratory Fitness

VO2 max (maximal oxygen uptake) is the gold standard measure of cardiovascular fitness — the maximum rate at which your body can use oxygen during exercise. It is measured accurately in exercise labs but can be estimated from resting heart rate, a 1-mile walk test, or sub-maximal exercise tests. Average values by age and sex: men 20–29: 42–51 ml/kg/min (good range). Men 50–59: 34–42 ml/kg/min. Women 20–29: 36–45 ml/kg/min. Elite athletes reach 60–85 ml/kg/min. VO2 max is strongly associated with

Improving Lung Function

Healthy lungs themselves cannot be significantly enlarged through training — lung volumes are primarily determined by genetics, age, and height. However, the muscles involved in breathing can be strengthened, improving respiratory efficiency. Aerobic exercise consistently improves oxygen extraction efficiency even without changing lung volumes. COPD patients benefit significantly from pulmonary rehabilitation — structured exercise programmes that improve exercise tolerance despite reduced lung f