Hey man great question,
There's no right answer here. But it comes down to this.
It depends on how you perceive the habit of smoking. So for example if deep in your mind you have this apprehensive negative opinion about your smoking being a bad habit then yes there are ways it can change your game.
The fact that you are asking if it affects your game clearly is an indication that you are pairing those two things together.
Instead, retrain your mind. Realize the decisions you make with cards are not related to anything else except your own decision during that time. Most buddies and players I play with (in the rare moments I am bankrolled to play live) they also smoke cigs and some herbs.
Perfect example is socially with a few drinks! Its fun and relaxing!
Another perfect example is I was watching a high level Omaha game at the casino and both players played a 4k pot it was a full house vs full house. The losing player stood up, poked a ciggy from his pack pursed it to his lips and walked away from the table to smoke outside and just cool off.
Its a perfect excuse when you lose a big hand to go for a cool off break (5-15 minutes) and light up a cigarrette. :bebored:
Having said that, if you are noticing some physiological health issues then its time to address the health issue on a deeper level and find another "substitute" habit.