Comment by growlist

Personal anecdata, I was drinking several cups of coffee to get myself through 7 hours' driving with a full work day spliced within. I used to feel absolutely dreadful. Why am I so tired despite drinking all this coffee? I used to think. I then started limiting myself to one small coffee a day. Bingo, all symptoms gone. The coffee was making me feel far worse than I would otherwise have done as it wore off, I believe.