I like those suggested titles too, but they kind of pre-suppose the result. What if playing video games lowers your blood pressure?
Actually, that would be an interesting extra thing to measure in your experiment. I, too, would tend to guess that your blood pressure goes up while you're actually playing, but what about an hour later? Is it possible that playing a game is relaxing in the longer term?
How about something like "Video Games: Is the pressure on?"