Exercising after quitting smoking is probably one of the BEST things you can do for your quit bc it gives you the "feel good" dopamine while quitting, and is a Positive activity we ALL need. Always check w/ your doctor before you start unless you're used to regular exercise too since TOO much exercise at one time can be harmful... for me, it was a fantastic way to dispel smoking thoughts and transform those thoughts into positives. I mean who wouldn't feel better knowing you're shaping, toning and improving your body as best that you can instead of neglecting your self-care?  Also, remember that during an early quit, yoga, stretching, breathing exercises, etc. are perfect for good health AND smoking cessation.