orthopnea
Orthopnea is breathlessness that comes on when a person lies flat and eases when they sit or stand up. A telltale sign is needing to prop oneself up on several pillows to sleep, or waking and reaching for the headboard to breathe more easily. The word combines the Greek for upright and breath, capturing exactly the position that brings relief.
The mechanism is a shift of body fluid. When you stand, gravity keeps some blood pooled in the legs and abdomen; when you lie down, that fluid redistributes back toward the chest, increasing the volume of blood returning to the heart and lungs. A healthy heart handles the extra load without complaint, but a failing left ventricle cannot, so pressure rises in the lung vessels and a little fluid seeps into the lungs, making flat breathing uncomfortable within minutes.
Orthopnea is a classic clue to left-sided heart failure, and clinicians often quantify it by asking how many pillows a patient sleeps on. It is not perfectly specific — severe lung disease, large abdominal fluid, or obesity can mimic it — but in someone with known or suspected heart disease it is a meaningful sign of congestion.
A woman with heart failure now sleeps almost upright in a recliner; lying flat in bed leaves her gasping within a minute or two.
Needing to sleep upright to breathe is the everyday face of orthopnea.
Recording orthopnea as the number of pillows used (for example, two-pillow or three-pillow orthopnea) gives a simple way to follow whether congestion is improving or worsening over time.