Respiratory and cardiopulmonary limitations to aerobic exercise capacity in adults born preterm

Adults born preterm, regardless of whether they develop bronchopulmonary dysplasia, have underdeveloped respiratory and cardiopulmonary systems. The resulting impaired respiratory and cardiopulmonary systems are inadequate for the challenges imposed by aerobic exercise, which is exacerbated by the presence of bronchopulmonary dysplasia. Thus the respiratory and cardiopulmonary systems of these preterm individuals may be the most influential contributors to the significantly lower aerobic exercise capacity compared with their term born counterparts. The precise underlying cause(s) of the lower aerobic exercise capacity in adults born preterm is not entirely known but could be a number of interrelated parameters including mechanical ventilatory constraints, impaired pulmonary gas exchange efficiency, and excessive cardiopulmonary pressures. Likewise, additional aspects, such as impaired cardiovascular function and altered muscle bioenergetics, may play additional roles in limiting aerobic exercise capacity. Whether or not all or some of these aspects are present in adults born preterm and precisely how they may contribute to the lower aerobic exercise capacity are only beginning to be systematically explored. The purpose of this mini-review is to outline what is currently known about the respiratory and cardiopulmonary limitations during exercise in this population and to identify key areas where additional knowledge will help to advance this area. Additionally, where possible, we highlight the similarities and differences between obstructive lung disease resulting from preterm birth and chronic obstructive pulmonary disease (COPD) as the physiology and pathophysiology of these two forms of obstructive lung disease may not be identical.