Breathing patterns during progressive incremental cycle and treadmill exercise are different

Perceived breathlessness at comparable minute ventilation (V(E)) is higher with cycling than with running. Different use of the upper extremities and chest wall may influence the breathing pattern. It was hypothetized that the relationship between tidal volume (V(T)) and V(E) throughout progressive incremental exercise is different with the two modes of exercise. Twelve well trained subjects (seven men) 20-25 years had incremental maximal exercise tests on a treadmill and a cycle ergometer on different days in random order. Heart rate, respiratory gases, V(E) and V(T) were measured on a computerized exercise testing system, and data were averaged over 20 s periods. The V(E)-V(T) relationship was characterized by maximum V(T), V(T) at a V(E) of 30 l min(-1) (V(T30)), the Hey plot and by a least squares quadratic regression model. The increase in V(T) by V(E) was steeper and V(T30) was higher with cycling compared to running. V(Tmax) was not different, but was achieved at a lower V(E) with cycling. Breathing strategies are different with running and cycling in young well trained subjects, and exercise mode must be accounted for in normative studies of breathing pattern.