Caffeine: How much is too much?

Caffeine: How much is too much?
By Mayo Clinic staff

http://www.mayoclinic.com/health/caffeine/NU00600

If you rely on caffeine to wake you up and keep you going, you aren't alone. Caffeine stimulates the central nervous system, alleviating fatigue and increasing wakefulness.
When to consider cutting back

For most people, moderate doses of caffeine — 200 to 300 milligrams (mg), or about two to four cups of brewed coffee a day — aren't harmful. But some circumstances may warrant limiting or even ending your caffeine routine. Read on to see if any of these apply to you.
'Grande' is your middle name

Though moderate caffeine intake isn't likely to cause harm, too much can noticeably affect your health. Heavy daily caffeine use — more than 500 to 600 mg a day, or about four to seven cups of coffee — can cause:

* Insomnia
* Nervousness
* Restlessness
* Irritability
* Nausea or other gastrointestinal problems
* Fast or irregular heartbeat
* Muscle tremors
* Headaches
* Anxiety

Even a little makes you jittery

To read the full article: http://www.mayoclinic.com/health/caffeine/NU00600