It was about 30 minutes into the workout when I started to notice my stomach hurt and I was having trouble catching my breath. I stood up and was dizzy so I went out to the lobby to lay down. I thought I was having a heart attack or something. It was very scary. My arms also started to tingle and stuff. After about 15 minutes, I felt better but was still nauseous. I'm still not sure whether it was because of the high doses of caffeine or what. I would rather do without the caffeine since I only decided to take Ripped Fuel to help burn off excess body fat and not as a strength gainer/workout supplement.