Any amount of smoking damages the heart and lungs and increases the risk of stroke.
Smoking is especially bad news for your heart because it’s a major cause of cardiovascular disease, which causes heart attacks, heart failure, arrhythmia (when the heart beats too slow, too fast, or irregularly), and chest pain. In fact, smoking causes one of every three deaths from cardiovascular disease. Smoking also increases the risk of stroke, which happens when blood supply to the brain is blocked. Stroke can cause severe disabilities like paralysis or trouble speaking.
Smoking is also really tough on your lungs, for a few different reasons. Smoking causes chronic obstructive pulmonary disease, also known as COPD. This includes illnesses like emphysema and chronic bronchitis, both of which make it difficult to breathe. Lung cancer is also the leading cause of cancer death in the US, and in most people, it’s caused by smoking.
The good news is that when you quit smoking, your body immediately begins repairing the damage. By three months, your risk of having a heart attack starts to drop, and your lungs begin functioning better.
Medical review: Nathan Cobb, MD, November 06, 2017