In patients with chronic obstructive pulmonary disease (COPD), various alterations of body composition are observed. Not only is cachexia frequently comorbid with COPD patients, but metabolic syndrome is also. The physical activity of COPD patients is important for their healthy status, and is associated with a mass of visceral fat and skeletal muscle. Although adiponectin, released from fat tissue, is known as cardioprotective and an anti-atherosclerotic factor, its levels in COPD patients were reportedly higher than in control subjects. Moreover, higher adiponectin levels were associated with higher mortality as a result of respiratory diseases. IL-6, a typical myokine produced from exercising skeletal muscles, has various effects, such as regeneration, growth, and proliferation of skeletal muscles. However, precise roles of muscle-derived IL-6 in exercising COPD patients have not been fully investigated.