Age is the main factor related to expiratory flow limitation during constant load exercise.

Objective: The objective of this study was to investigate the interaction among the determinants of expiratory flow limitation (EFL), peak oxygen uptake (VO2peak), dysanapsis ratio (DR) and age during cycling at different intensities in young and middle-aged men.

Methods: Twenty-two (11 young and 11 middle-aged) men were assessed. Pulmonary function tests (DR), cardiopulmonary exercise tests (VO2peak) and two constant load tests (CLTs) at 75% (moderate intensity) and 125% (high intensity) of the gas exchange threshold were performed to assess EFL.