Why do I wheeze when I lie down?

Wheezing that appears when you lie down has two main explanations, and telling them apart matters. Asthma is the common one: airways naturally narrow at night - circadian rhythm dips the hormones that keep them open - lying down increases blood flow to the lungs and chest wall, and post-nasal drip and dust-mite-heavy bedding pile on. NHLBI lists nighttime symptoms as a hallmark of undertreated asthma, and a wheeze that wakes you or greets you at the pillow is the classic uncontrolled-asthma signal. The second explanation is the heart: when the heart struggles, lying flat floods the lungs with fluid, producing breathlessness when flat - relieved by propping up on pillows - sometimes with a wheeze called cardiac asthma, usually with leg swelling and daytime breathlessness too. For the asthma pattern: take the wheeze to a provider - nighttime wheeze usually earns an inhaler trial and often a preventer, and it responds well. Meanwhile wash bedding hot weekly, keep the bedroom cool and dust-light, and do not smoke. For the heart pattern - breathlessness flat on your back, needing extra pillows to breathe, leg swelling, waking gasping an hour or two after falling asleep: prompt assessment, not routine. NHLBI lists these among heart failure's classic symptoms, and they move the timeline to days, not months. Emergency version: sudden severe breathlessness with chest pain, blue lips, or inability to speak full sentences - call an ambulance. Pymander is a free AI doctor, 24/7 by text. Describe the wheeze and what comes with it, and it can help you read the pattern.