Smoking can cause lungs to look blackened, inflated, and inflamed, but some of the damage is reversible. Depending on the extent of the damage, it could take years for your lungs to regain a healthy, ...

Smoking decreases blood oxygen and makes the heart and lungs work harder, leading to fatigue. Nicotine in tobacco can also cause an adrenaline rush, leaving someone feeling tired when it wears off.

Add Yahoo as a preferred source to see more of our stories on Google. Lung cancer rates and deaths have fallen precipitously in recent decades overall — but diagnoses are rising for nonsmokers. (Getty ...