[Maximal forced expiration indices in young symptom-free smokers].

The indices of maximal forced expiration were investigated spirographically, with flowmeter of Wright and pneumotachorgaphically in 205 symptonless smokers and 154 healthy subjects, aged 18 to 28. In 16.7 to 26.7 per cent of the young symptomless smokers with normal forced vital capacity and forced expiratory volume per second, anomalies in some of the indices, determined pneumotachographically were found, namely MMEFR75--85, T25--75, V25, PEFR/V25.