Most likely it's just a coincidence. Drinking coffee within reasonable limits cannot harm the body.Would you mind reading this website to find out how important it is to drink water during a workout? The essential beverage should be water during and after the workout. You can drink no more than a cup of americano after one hour when you finished the training. But, my trainer generally doesn't allow me to drink coffee. I gave up drinking coffee, almost three months. I noticed that I had terrible headaches, and I didn't know what caused them. The trainer suggested I get rid of the coffee for a while. It worked! No more headaches. I feel fantastic.