In the lungs, it increases tissue inflammation, narrowing airways and allowing less oxygen to the body. Since working muscles need more oxygen, this could result in less strength and energy during exercise.

Does smoking affect your gym workout?

The nicotine and carbon monoxide from smoking may make your blood “sticky” and your arteries may become narrow. Narrow arteries reduce the flow of blood to your heart, muscles, and other body organs, making exercise harder. ... If your muscles don't get oxygen fast enough, your body can't work as well.

Can you still be fit and smoke?

A new book called A Smoker's Guide to Health and Fitness explains how to make the best of a bad habit. (But you should probably still quit.)