Question: Will drinking coffee or taking some form of caffeine help my workout?
Answer: Taking on a source of caffeine before your workout can actually enhance the quality of your workout, it can enhance your performance and your power during your workout. Also, it can actually increase your body's use of fat as an energy source during your workout. So your body's able to actually use fat as fuel more effectively when you have caffeine before it.
Caffeine pre-workout can also decrease that perceived exertion so that workout doesn't seem as hard when you have that caffeine before it. So go ahead, have that caffeine, have a cup of coffee, have a diet soft drink. As long as you're not dehydrating yourself, as long as you're not having the caffeine in place of hydrating beverages. A little bit of caffeine pre-workout is completely okay.
What you don't want to do though is caffeine stimulant pills. These are gonna have combinations of lots of different herbs, lots of different compounds that are not just caffeine and they're all gonna be interacting together and you don't know how that can impact you. It can raise your heart rate, raise your blood pressure, increase your risk of stroke or seizure, even.
So, if you're having caffeine from a beverage -- that's pretty straightforward, you know what you're getting. Fine, have that pre-workout. But as far as caffeine pills and stimulant pills? Avoid them at all cost pre-workout.