We propose that spirometry, a practical and validated marker of respiratory function, is also an overlooked marker of global human health throughout a person’s life span, from infancy to old age, because it not only relates to respiratory diseases, but it also identifies individuals at risk of suffering other prevalent chronic non-communicable diseases (NCDs), particularly cardiovascular and metabolic disorders. Accordingly, we propose that spirometry be performed in infancy, adolescence, early and late adulthood.