Each day I drink lots of coffee and energy drinks (redbull 355ml cans). I go to gym 3 times a week (on evenings). Are there any effects on my workouts? I stopped drinking any caffeine (at least from coffee and energy drinks) for 3 weeks and didn't feel any changes. Not during daytime nor before, during or after my workouts. My friends often tell me that my heart will explode from such huge amounts of caffeine (I read about caffeine OD and felt "caffeine induced disorders" symptoms).
My question is what's the effect of caffeine on heart/body when person is working out?