A charity has set up an "online breath test" which can help detect lung problems.
People who get out of breath doing every day tasks such as walking up stairs have been encouraged to take the online test by the British Lung Foundation (BLF).
The charity said that millions of people across the UK could have the lung condition chronic obstructive pulmonary disease (COPD) and are not even aware that they have it.
COPD is used to describe a number of conditions including emphysema and chronic bronchitis.
Every year 115,000 people are diagnosed with COPD across the UK but the BLF said this figure is the "tip of the iceberg".
BLF chief executive Dr Penny Woods said: "COPD isn't just a smokers' disease. It usually develops because of long-term damage to your lungs from breathing in a harmful substance, usually cigarette smoke, as well as smoke from other sources and air pollution.
"Jobs where people are exposed to dust, fumes and chemicals can also contribute to developing COPD. That could be anyone.
"We're aware of 1.2 million diagnosed with the condition but that's the tip of the iceberg. Millions have this life-limiting lung disease, and they don't even know it."
Symptoms of COPD include having a cough that lasts a long time, wheezing in cold weather and producing more phlegm than usual.
The test can be found at: www.blf.org.uk/breathtest
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