5 Signs You're Drinking Too Much Coffee With an export industry alone that is worth $20 billion, chances are a lot of people drink too much coffee. MSN compiled this list to help heed the signs of too much "morning Joe." 1 The National Institute of Mental Health recommends 2 E.U. scientists discovered that certain compounds in coffee can actually increase the production of stomach acid. 3 Heart palpitations can be a sure sign of too much coffee. They often lead to dizziness and fainting. 4 Studies have shown that coffee can stay in a person's system for up to 14 hours. This can wreak havoc on a sleep cycle. 5 Five cups of coffee or more a day