Caffeine & Dehydration

Caffeine comes in various liquid products, like coffee, hot and iced teas, colas and other sodas and energy drinks. Liquid fights dehydration, but caffeine is often said to be a diuretic that dehydrates you even if you drink it. That reputation is unfair, according to nutritionist Katherine Zeratsky of the Mayo Clinic, because only very large amounts of caffeine act as a diuretic and increase urination.

Definition

Dehydration occurs when your body does not have enough liquid to function properly. This condition happens when you do not drink enough and lose liquids too rapidly without replacing them. Sweating, diarrhea and vomiting are three of the most common dehydration causes, according to PubMed Health. Diuretics that make you urinate excessively contribute to the problem. Mild dehydration is easily overcome by drinking enough liquid, but severe cases are dangerous and require medical care such intravenous fluid replacement.

Caffeine Effects

Caffeine is anecdotally reported to be a diuretic that increases your need to urinate, potentially dehydrating you if you do not drink enough non-caffeinated liquid to replenish the loss. The moderate amounts of caffeine consumed by most people have no dehydrating effect, Zeratsky says. The substance is not a diuretic unless you consume more than 500 mg per day, which translates to at least four to seven cups of coffee. A 2002 literature review by Larry Armstrong, an exercise and environmental physiology professor at the University of Connecticut, found that caffeine's diuretic effect is the same as that of plain water, which also increases urination.

Symptoms

Dehydration causes some easily recognizable symptoms, whether it is caused by excess caffeine consumption, overexertion, illness or anything else. Your mouth gets dry and sticky, your eyes look sunken in and stop producing tears, your urine is sparse and dark yellow and you start to feel lethargic, which can lead to a coma if you are not treated, according to PubMed Health. Nausea, vomiting, diarrhea and a queasy stomach sometimes accompany dehydration.

Treatment

Mild dehydration is treatable with cool water or sports drinks enriched with carbohydrates and electrolytes. These beverages are preferable to caffeinated sodas, coffee and tea and other non-caffeinated drinks to quickly replenish the liquids of a dehydrated person. People who are severely dehydrated need to go to an emergency room where they can be more quickly replenished with an IV.

Considerations

Too much caffeine increases urination, and it often triggers other unpleasant symptoms. In moderate doses, it helps you stay alert, but the National Sleep Foundation warns that too much affects your coordination, gives you a headache, increases your heart rate and makes you irritable and anxious. Excessive caffeine gives you insomnia and causes a crash when it finally wears off. Avoid these problems by limiting your caffeine intake to less than 500 mg per day.