Dysanapsis is a determinant of expiratory flow limitation during exercise in master athletes

Previous research has identified expiratory flow limitation (EFL) as a limiting factor to exercise performance in older endurance athletes (i.e. master athletes), who represent a model of successful aging. A mismatch between airway size and lung size, termed dysanapsis, has been proposed as a contributor to EFL during exercise. We thus investigated whether dysanapsis determine the prevalence and severity of EFL in master athletes during exercise.

Four female and fourteen male master athletes (age, 67 ± 5 years; V̇O_2max, 50.9 ± 5.7 mL.min^-1.kg^-1) performed an incremental exercise test to exhaustion on a cycle ergometer. The maximal expiratory flow volume (MEFV) curve was assessed at rest and operational lung volumes were determined with participants performing inspiratory capacity maneuvers at each exercise workload. EFL severity was estimated as the percentage of the tidal expiratory volume that overlapped the MEFV curve. Dysanapsis was quantified using spirometry-derived indices.

All participants started experiencing EFL at workloads (W_EFL) ranging from 40 % to 100 %PPO (W_EFL = 68 ± 20 %PPO). EFL severity reached 46 ± 21 % at peak exercise. Lower values across dysanapsis indices, reflecting smaller airway size for a given lung volume, were correlated with lower W_EFL (r²>0.490, P < 0.001) and greater EFL severity (r²>0.243, P < 0.038). Individuals experiencing EFL at lower intensities (i.e. lower W_EFL) showed greater EFL severity (r²=0.571, P < 0.001).

Our results suggest that dysanapsis is a key determinant of EFL in master athletes, likely contributing to its earlier onset at lower workloads and to its increased severity. These findings have implications for understanding respiratory limitations during exercise in older adults.