Orthopnea is best described as shortness of breath in which position?

• A. Shortness of breath when standing
• B. Shortness of breath when sitting
• C. Shortness of breath during exertion
• D. Shortness of breath when lying flat

Answer: (D)

Orthopnea is dyspnea that worsens when you lie down and improves when you sit up. The reason lies in how body position affects fluid distribution and heart function. When lying flat, fluid that has pooled in the legs returns more readily to the chest, increasing venous return to the heart. In left-sided heart failure, the left ventricle struggles to handle this extra volume, raising pressure in the pulmonary circulation and causing pulmonary congestion and shortness of breath. Sitting up or standing uses gravity to pull some of that fluid away from the chest and reduces pulmonary venous congestion, making breathing easier. That positional nature is why shortness of breath when lying flat is the hallmark. Shortness of breath during exertion happens with many conditions and is not tied to position, while shortness of breath upon standing or sitting isn’t the characteristic pattern of orthopnea.