The Mayo Clinic checks back in with a message that too much coffee can cause problems. After suggesting that two to four cups a day shouldn’t cause problems, the Clinic sounds a warning bell for people habitually drinking more than four cups of coffee a day. Such people, the Mayo says, are at increased risk of:
- Insomnia
- Nervousness
- Restlessness
- Irritability
- Stomach upset
- Fast heartbeat
- Muscle tremors
Livestrong adds a few other negative side effects of drinking coffee to the list. These side effects include:
- Cardiovascular changes
According to Livestrong, caffeine has a direct impact on your heart rate and can cause your heartbeat to become irregular or rapid as your caffeine intake becomes excessive. These changes, Livestrong reports, can be serious enough to result in a heart attack or death. Breathing may become more difficult as caffeine intake increases. Blood vessels can dilate, restricting blood flow to vital organs.
- Gastrointestinal upset
According to Livestrong, too much coffee can affect your stomach and digestive system. Nausea, vomiting, and diarrhea are three problems that can hit habitual coffee drinkers. Dehydration is a possibility as a result of vomiting and because of the diuretic effect of coffee, which can cause excessive urination.
- Mental change
This is a possible side effect most people probably don’t want to think about. But every coffee drinker has probably noticed changes in his or her mental state after having had a few cups too many. At first you may feel more alert, but Livestrong warns that, as your consumption increases to unsafe levels, you’re likely to start feeling “disoriented, dizzy or ‘foggy-brained’ because of the caffeine’s effect on your central nervous system.” Livestrong goes on to warn, “You may also experience hallucinations or you may start to feel confused.”