Caffeine can also exacerbate the condition of patients who are suffering from certain heart ailments, so this is why they are encouraged to lessen their caffeine intake. However, there are also studies that show that caffeine does the opposite since it is a vasodilator. To avoid confusion, you should only take in the recommended dosage daily, and the recommended amount is only about 200 to 300 milligrams per day. Again, some experts also believe that 100 mg of it is enough daily.