Low resting inspiratory capacity (IC) in patients with COPD was linked to worse symptoms and greater mortality, according to research published in the Journal of Applied Physiology.

Researchers conducted a 10-year study of 285 COPD patients to examine the interaction between resting IC and maximal inspiratory pressure (MIP), exertional dyspnea, exercise capacity, and long-term survival.

According to researchers, “low resting IC was consistently linked to heightened dyspnea intensity, low V̇o2peak, and worse survival in COPD even after accounting for airway obstruction, inspiratory muscle strength, and diffusing capacity.”

“To our knowledge, this study is the first to show an independent association between low resting inspiratory capacity (IC) and, severe exertional dyspnea, exercise limitation, and increased mortality risk, after accounting for the severity of airway obstruction, inspiratory muscle strength, and diffusing capacity,” the authors wrote. “These results support the use of resting IC as an important independent physiological biomarker closely linked to key clinical outcomes in COPD.”