Cardiopulmonary stress during exercise training in patients with COPD

Exercise training is an essential component of pulmonary rehabilitation. However, the cardiopulmonary stress imposed during different modalities of exercise training is not yet known. In the present study, the cardiopulmonary stress of a 12-week exercise training programme in 11 chronic obstructive pulmonary disease (COPD) patients (forced expiratory volume in one second 42+/-12%pred, age 69+/-6 yrs) was measured. Pulmonary gas exchange and cardiac frequency (f(C)) of three training sessions were measured with a portable metabolic system at the beginning, mid-term and end of the programme. Symptoms were assessed with Borg scores. The exercise intensity was compared with the recommendations for exercise training by the American College of Sports Medicine (ACSM). Training effects were significant (maximum change in work: 14+/-11 Watts, 6-min walk test: 44+/-36 m). Whole body exercises (cycling, walking and stair climbing) consistently resulted in higher cardiopulmonary stress (oxygen uptake (V'(O(2))), minute ventilation and f(C)) than arm cranking and resistance training. Dyspnoea was higher during cycling than resistance training. Patients exercised for >70% (>20 min) of the total exercise time at >40% of the V'(O(2)) reserve and f(C) reserve ("moderate" intensity according to the ACSM) throughout the programme. The cardiopulmonary stress resistance training is lower than during whole-body exercise and results in fewer symptoms. In addition, exercise testing based on guidelines using a fixed percentage of baseline peak performance and symptom scores achieves and sustains training intensities recommended according to the American College of Sports Medicine.