Physical training and testing in patients with chronic obstructive pulmonary disease
Authors: Arnardóttir Ragnheiður Harpa 
Published: June 2007

Introduction:  The effects of different training modes need to be investigated further in patients with chronic obstructive pulmonary disease (COPD). Both advanced laboratory tests and field tests are used in patients with COPD to evaluate effects of interventions such as pulmonary rehabilitation.

Aims:  The overall aims of the studies were to investigate the effects of different training modalities on exercise capacity and on health‐related quality of life (HRQoL) in patients with moderate or severe COPD and, further, to explore two of the physical field tests used in pulmonary rehabilitation, the 12‐min walk test and the incremental shuttle walking test (ISWT).

Materials and Methods:  Patients with moderate or severe COPD were included. In study I (n = 57), the 12‐min walk test was performed three times within 1 week. Exercise‐induced hypoxemia (EIH) was assessed by pulse oximeter and was defined as SpO2 < 90%. In study II (n = 93), performance on ISWT was compared to performance on two different cycle tests. In study III (n = 42), the effects of two different combination training programmes were compared when training twice a week for 8 weeks. One programme was mainly based on endurance training (group A), and the other was based on resistance training and on callisthenics (group B). In study IV (n = 60), endurance training with interval resistance was compared to endurance training with continuous resistance.

Results:  In study I, the 12‐min walking distance (12MWD) did not increase on retesting in patients with EIH, but increased significantly on retesting in the non‐EIH patients. In study II, the ISWT was as good a predictor of peak exercise capacity (W peak) as peak oxygen uptake (VO2 peak) was. In study III, W peak and 12MWD increased in group A but not in group B. HRQoL, anxiety and depression were unchanged in both groups. Ratings of perceived exertion at rest were significantly lower in group A than in group B after training and during 12 months of follow‐up. Twelve months post training, 12MWD was back to baseline in group A, but was significantly shorter than at baseline in group B. Patients with moderate and severe COPD responded to training in the same way. In study IV, both interval and continuous endurance training increased W peak, VO2 peak, peak exhaled carbon dioxide (VCO2 peak) and 12MWD. Likewise, HRQoL, dyspnoea during activities of daily life, anxiety and depression improved similarly in both groups. At a fixed, sub‐maximal workload (isotime), the interval training reduced oxygen cost and ventilatory demand significantly more than the continuous training did.

Conclusions:  EIH affects the retest effects on 12MWD. W peak can be predicted from an ISWT similarly well as from VO2 peak. A short training programme can improve W peak and 12MWD when based mainly on endurance training. Both patients with moderate and severe COPD respond to training in the same way. A short endurance training intervention can possibly delay decline in 12MWD for 1 year. Both interval and continuous endurance training improves physical performance and HRQoL. Interval training lowers the energy cost of sub‐maximal work more than continuous training does.