In a new campaign, Public Health England says too many smokers remain unaware of the risks of chronic obstructive pulmonary disease (COPD).
COPD, which narrows the airways, can leave people struggling to do simple tasks such as climbing stairs.
Figures show more than 1m people in England are living with it, with nine in 10 cases caused by smoking.
COPD is actually the umbrella term for a number of serious lung conditions including chronic bronchitis and emphysema.
People with the disease have difficulties breathing, primarily due to the narrowing of their airways and destruction of lung tissue.
Typical symptoms include breathlessness when active, a persistent cough and frequent chest infections.
But in the Public Health England (PHE) campaign, experts say smokers often dismiss the early signs as a "smoker's cough" but, by continuing to smoke, the condition can get worse and damage their quality of life.
While there is no cure, stopping smoking, tailored exercise programmes and medication can slow the progression of COPD.
To raise awareness about the disease, PHE's short film will run on the internet.
It features former Olympic athlete Iwan Thomas, whose mother was recently diagnosed with COPD, doing an experiment with smokers to see what COPD is like.
Mr Thomas said: "I've never fully understood COPD or the everyday consequences, but when the simple things like climbing the stairs, making a cup of tea or walking to the bus stop become impossible, it is serious.
"After years of smoking, it is great that my mum is making 2016 the year she quits and I'd urge anyone who smokes to do the same."
Prof Dame Sally Davies, England's chief medical officer, added: "COPD is a serious lung disease and is not particularly well known.
"The single best thing a smoker can do to reduce their chances of developing this devastating disease and prolong their life is to stop smoking."
Smokers are being urged not to dismiss the early signs of a debilitating disease as simply a smoker's cough.