Relationship between peripheral muscle structure and function in patients with chronic obstructive pulmonary disease...

Area of Science:

• Pulmonary Medicine
• Exercise Physiology
• Nutritional Science

Background:

• Chronic Obstructive Pulmonary Disease (COPD) is associated with peripheral muscle dysfunction.
• The relationship between muscle structure (mass) and function (strength, endurance, aerobic capacity) in COPD patients with varying nutritional states requires further investigation.
• Understanding these relationships is crucial for developing effective rehabilitation strategies.

Purpose of the Study:

• To investigate the associations between peripheral muscle mass and muscle function (strength, endurance, maximal aerobic capacity) in COPD patients.
• To compare these relationships between COPD patients with different nutritional statuses and healthy controls.

Main Methods:

• Thirty-nine moderate-to-severe COPD patients and 17 healthy controls underwent isokinetic, isometric, and endurance strength testing of knee extensor muscles.
• Maximal aerobic capacity was assessed using a maximal cardiopulmonary exercise test (peak oxygen uptake [VO(2)] peak).
• Muscle mass (MM) was quantified using dual-energy x-ray absorptiometry.

Main Results:

• COPD patients exhibited significantly reduced muscle strength (peak torque, total work) and maximal aerobic capacity compared to controls.
• Significant relationships between muscle mass and strength/endurance were observed in COPD patients with preserved muscle mass and in controls.
• Strength normalized for mass improved in both COPD subgroups, but maximal aerobic capacity remained reduced in all COPD patients.

Conclusions:

• Muscle atrophy is a primary driver of strength reduction in moderate-to-severe COPD.
• Reduced endurance in COPD appears linked to oxygen delivery/consumption imbalance rather than solely local muscle structure.
• Peripheral muscle mass is not a reliable predictor of maximal aerobic capacity in COPD patients, highlighting the need for comprehensive fitness interventions.