Physiological Response to Moderate Exercise Workloads in a Pulmonary Rehabilitation Program in Patients With Airflow Obstruction: Rehabilitation Program

The patients performed an incremental symptom-limited cycle ergometer test that included a 3-min rest period and 3 min of unloaded pedaling, followed by an increase in work rate (WR) of 10 W every minute from a starting work rate of 20 W until exhaustion was apparent from the inability to maintain the pedaling cadence above 40 revolutions/min. The peak WR was defined as the highest work level reached and maintained for a full minute.
Rehabilitation Program
The rehabilitation strategy was a comprehensive program that included modalities of exercise training, breathing control techniques, disease education, and instruction in the use of medication. There was no weight training component. The exercise training component consisted of the following sequence: (1) cycling on a calibrated cycle ergometer (824E; Monark; ); (2) walking on level ground; and finally (3) walking on an inclined nonmotorized treadmill (Woodway; Waukesha, WA) for a total of 60 min (including periods of rest) twice weekly for 12 consecutive weeks. The exercise training protocol is shown in Figure 1. Monitoring during exercise sessions was conducted by a physiotherapist and involved measurements of HR and Sao2.
The initial exercise level for cycling was defined as previously described by Niederman et al, namely 50% of the maximal WR attained in the baseline incremental symptom-limited cycle ergometer evaluation. Hence, at the first exercise session, patients cycled at this workload for 20 min unless symptomatic (leg pain, severe dyspnea) or physiologic end points (a HR > 80% of the maximal age-predicted HR or Sao2 < 85%) were exceeded earlier. At subsequent sessions, this same WR was applied until the patient could sustain it for 20 min.

The exercise prescription was revised weekly by a physiologist. Once an individual could exercise at the prescribed work level for 20 min, the WR was increased by approximately 25%, and again this level was continued until it could be sustained for 20 min. Following the completion of cycling exercise, the patients walked on the horizontal for 10 min at a training intensity that was targeted at the highest pace that could be tolerated by each individual patient. The targeted walking speed was gauged to result in a HR of approximately 70% of the maximal age-predicted HR. Walking on the horizontal was subsequently followed by five 1-min bouts on a treadmill with 10% inclination at a speed of 3.0 km/h, unless the previously described symptomatic or physiologic end points were exceeded earlier. The patients who were unable at the beginning of the program to exercise for a full minute were allowed to stop before attempting again. Each 1-min bout was followed by 1 min of rest. The walking exercise prescription was kept constant throughout the 12 weeks. The patients exercised at a fairly steady WR for the entire duration of the three exercise modes, with only 5 min of cool-down periods on the bicycle ergometer at a low pedaling frequency, and three 5-min rest periods in between the remaining exercise modes (Fig 1).

Figure 1. Diagram of the exercise rehabilitation training program.

Figure 1. Diagram of the exercise rehabilitation training program.