What Are the Side Effects of Too Much Caffeine?

Drinking too much coffee can cause you to feel jittery and lose sleep.
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Caffeine, usually in the form of coffee, tea, caffeinated sodas and energy drinks, is often consumed to increase cognitive functioning and improve a bad mood.

Judging by the length of the waiting line at Starbucks, this must be especially true in the mornings.

Many of us feel like we can't function until we get our first cup (or two) of coffee. That's totally fine, but what happens if you drink three, four or more cups?

 How much caffeine is too much? 

Caffeine is a stimulant, and some studies show that small amounts of caffeine may improve your mental response-time. Other studies show that cognitive improvements and mood elevation may not be due to the beneficial aspects of caffeine, but to ending the withdrawal symptoms, you feel when you haven't had your morning "fix" yet.

How Much Caffeine Is Safe?

It seems that experts who study caffeine agree that consuming up to 300 milligrams of caffeine per day is safe -- for adults anyway. That's roughly the amount of caffeine you would get from three cups (not mugs or big paper cups) of coffee. 

Women who are pregnant or may become pregnant may want to decrease that amount or skip the caffeine altogether. 

Less is known about caffeine use in kids -- but gulping down the energy drinks before school is probably a lousy idea.

What Happens When You Consume Too Much Caffeine?

Consuming more than 300 milligrams of caffeine per day may give you the "caffeine jitters," which is that jumpy and slightly alarmed feeling.

 Larger amounts of caffeine may make you irritable, sleepless, and may even trigger anxiety and cause diarrhea.

Caffeine can act as a diuretic, so people assumed that drinking too much coffee or other caffeinated beverages would cause dehydration.  However, researchers found that your body adjusts to your caffeine intake so drinking caffeinated beverages won't increase your need for water.

Reduce Your Caffeine Intake (Or Eliminate It Altogether)

Kicking the caffeine habit cold turkey isn't good. Caffeine withdrawal can give you headaches, make you crabby, give you muscle aches and generally make you feel miserable for a few days. The withdrawal symptoms will pass after a week or so, but blending regular caffeinated beverages with decaf for a few days might help with the transition.

Sources:

Armstrong LE, Pumerantz AC, Roti MW, Judelson DA, Watson G, Dias JC, Sokmen B, Casa DJ, Maresh CM, Lieberman H, Kellogg M. "Fluid, electrolyte, and renal indices of hydration during 11 days of controlled caffeine consumption." Int J Sport Nutr Exerc Metab. 2005 Jun;15(3):252-65.

Rogers PJ, Dernoncourt C. "Regular caffeine consumption: a balance of adverse and beneficial effects for mood and psychomotor performance." Pharmacol Biochem Behav. 1998 Apr;59(4):1039-45.

Smith AP., "Caffeine at work." Hum Psychopharmacol. 2005 Aug;20(6):441.

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