When it comes to COPD, one of the most devastating issues that affects patients is the degradation of their muscles and respiratory functions as well as the development of exercise intolerance. All of these issues are linked to a significant drop in quality of life as well as a patient’s prognosis. It is important, then, to understand what leads to this muscle breakdown and how it can be combated or, at the very least, treated.

Skeletal muscle dysfunction contributes to exercise intolerance and further muscle depletion in COPD patients. Muscle strengthening exercises using resistance training has therefore been recommended for COPD rehabilitation, which usually also includes endurance training such as cycling or walking. COPD rehabilitation efficiently improves exercise capacity, health-related quality of life (hrQOL) and reduces days of hospitalization – and, as a result, it is now part of standard COPD treatment. The effects and benefits of resistance muscle training, however, have been unclear.

In this blog post, we’re going to systematically evaluate the evidence for comparing the effect of combined resistance and endurance training to endurance training alone.

Key Findings

• Skeletal muscle dysfunction contributes to exercise intolerance and further muscle depletion in COPD patients.
• COPD rehabilitation improves exercise capacity and quality of life (QOL), but usually includes endurance training only.
• The systematic review shows that both strength and endurance training improve QOL, exercise capacity, maximal oxygen uptake and activities of daily living with no difference between the groups.
• Muscle strength training is still recommended as it reduces risk of mortality in COPD patients.

Patient Impact

Both Muscle strength and endurance training improve exercise capacity, oxygen uptake and QOL in COPD, while muscle strength training also reduces mortality risk.

Study Methods

Randomized control trials (RCTs), systematic reviews and guidelines based in RCTs that compared the effects of combined training to endurance training alone were included in the analysis. Primary outcomes measured included hrQOL, activities of daily living, mortality, adverse events, dyspnea. Secondary outcomes measured included walking distance, muscle strength, lean body mass and exercise capacity.

Study Results

Eleven studies including 331 participants qualified. Training duration was three to 12 weeks, with two to three sessions per week. Resistance training included upper and lower body muscles with incremental increase in load during training. Endurance training included cycle ergometer and/or treadmill exercises. No significant differences in hrQOL, activities of daily living, six-minute walk test and maximal oxygen uptake between the groups, but a significant increase in muscle strength in the combined training group.

Combination of resistance and endurance training leads to increased muscle strength when compared to endurance training alone, but to no changes in hrQOL, exercise capacity, daily living activities or oxygen uptake. However, combined training is recommended, as decreased muscle strength contributes to COPD mortality, independent of lung function. The demonstrated muscle strengthening effect could therefore reduce mortality.

References

Iepsen UW et al. A systematic review of endurance, resistance and combined exercise training in COPD. ERJ 2014;44(Suppl 58):3033.