Strenuous exercise may cause progressive and proportional haemodynamic overload damage to the alveolar membrane, even in athletes. Despite the high incidence of arterial desaturation reported in endurance athletes has been attributed, into other factors, also to the damage of the alveolar-capillary membrane this evidence is equivocal. Some studies demonstrated flood of the interstitial space and consequent increase in pulmonary water content, but most of them were able to show this through indirect signs of interstitial oedema. The present review illustrates the literature's data in favour or against pulmonary interstitial edema due to intense exercise in athletes.