Shortness of breath when walking up stairs

Congestive heart failure

Your heart's not pumping as well as it should, so fluid could build up in your lungs when you exert yourself. This makes it feel like you can't catch your breath.

Chronic obstructive pulmonary disease

Damage to your lungs makes it harder to exhale air, so you can't get enough oxygen during activity. You'll likely feel very winded and cough.

Asthma

Your airways tighten and swell up when you exercise, making it harder for air to get through. You'll feel wheezy and breathless.

Obesity

Excess weight puts extra strain on your heart and lungs, making them work harder and less efficiently when you need more oxygen.

Anemia

You have fewer red blood cells to carry oxygen, so your body struggles to meet the increased demand when you climb stairs. You'll feel tired and short of breath.

Deconditioning

Your body isn't used to physical activity, so your heart and lungs don't respond efficiently to the sudden increase in demand. You'll feel winded quickly.

Pulmonary embolism

A blood clot has lodged in your lungs, stopping blood flow and oxygen. It'll feel like a sudden, sharp difficulty breathing.

Pulmonary hypertension

Blood pressure in your lungs' arteries is too high, making it hard for your heart to pump blood through them. This causes breathlessness during exertion.

Arrhythmia

An irregular heartbeat means your heart can't pump blood effectively, especially when your body needs more oxygen during exertion. You might feel palpitations too.

Interstitial lung disease

Scarring in your lung tissue makes it stiff and reduces its ability to transfer oxygen. This makes deep breaths and exertion very difficult.