What it means
Dyspnoea is the subjective sensation of uncomfortable or difficult breathing. From the Greek dys, difficult, and pnoe, breathing.
Two qualifiers carry particular diagnostic weight, both pointing towards the heart:
- Orthopnoea — breathlessness on lying flat, relieved by sitting up. Ask how many pillows a person sleeps on, and whether that number has changed.
- Paroxysmal nocturnal dyspnoea — waking abruptly, hours after falling asleep, gasping for breath and needing to sit or stand.
Breathlessness is graded by what it prevents — walking on the flat, climbing stairs, dressing — which is more informative than any adjective.
In practice
Recorded as "SOB" or "SOBOE" (short of breath on exertion) in notes, and graded on the MRC dyspnoea scale from 1 to 5.
"Tachypnoea" is a raised breathing rate, which is measured; dyspnoea is what the person feels.
Why it matters
Breathlessness developing over weeks to months warrants investigation of both heart and lungs. Anaemia and thyroid disease are common, correctable and frequently overlooked causes.
Sudden breathlessness, breathlessness with chest pain, or breathlessness with a swollen painful calf requires emergency assessment.
Clinically reviewed by Dr Mohammad Zubair Khan, GMC 7563469
Last reviewed
August 30, 2026