The majority of the human body is composed of water, and when people do not have enough water in their bodies dehydration occurs. Dehydration can cause sickness, low blood pressure, fatigue and other health problems that become more serious and can lead to death if untreated. Alcohol and caffeine are two drugs that can dehydrate the body in a variety of ways. Knowing how alcohol and caffeine affect your body's fluid levels can help you ward off dehydration.
Dehydration
Dehydration is caused by fluid loss or not drinking enough liquids. In a dehydrated state, the body does not have enough fluids to function properly. Symptoms of dehydration include a dry mouth, dark yellow urine, low urine output, sunken eyes, a lack of tears, low blood pressure, rapid heartbeat and a lethargic or comatose state. In mild forms, dehydration can be treated by increasing your fluid intake. For more severe dehydration, hospitalization and IV fluids are used to pump fluids back into the body. If left untreated, dehydration can lead to brain damage, seizures and even death.
Alcohol
Alcohol is a diuretic, which means it causes a greater loss of fluids than gains when you drink it. Alcohol increases urination, which makes you lose more water, electrolytes and minerals in your body than you normally would. Alcohol decreases your production of antidiuretic hormone, which is used by your body to reabsorb water. With the antidiuretic hormone blocked, you lose more fluids due to increased urination. According to doctors Robert Smith and Dena Davidson, drinking 50 grams of alcohol in about 8 ounces of water -- or about four 2-oz. shots of liquor -- can cause you to lose up to 1 quart of liquid as urine.
Alcohol Dangers
Excess alcohol consumption can lead to vomiting, which depletes fluids in the body and spurs dehydration. The effects of alcohol vary from person to person, but in general the less a person weighs, the less alcohol it takes to cause dehydration or vomiting. Binge drinking -- rapidly downing drinks in succession -- increases your chances of becoming dehydrated from alcohol. Binge drinking is the main cause of alcohol poisoning, which affects your heart rate, breathing and gag reflex and can be fatal. People suffering from alcohol poisoning also suffer from dehydration, and IV fluids are often injected into the body to replace lost fluids.
Caffeine
Caffeine can also produce a diuretic effect in large doses. According to the Mayo Clinic, moderate doses of caffeine --- 200 to 300 mg, or about two to four cups of brewed coffee a day --- won't produce harmful effects in healthy individuals. Large doses of caffeine can cause vomiting, however, which decreases your body's fluid levels and can lead to dehydration. Moderate amounts of caffeine do not produce a diuretic affect, according to "Good Morning America" medical contributor Dr. Marie Savard, but in large doses, caffeine can act as a diuretic and increase urination, leading to dehydration. If you keep your daily caffeine intake in the 200-to-300-mg range and you drink at least eight 8-oz. glasses of water a day, you should be safe from dehydration.
References
- MayoClinic.com: Alcohol use: If You Drink, Keep it Moderate; March 2011
- PubMed Health: Dehydration; August 2009
- MedlinePlus: Caffeine in the Diet; May 2011
- MayoClinic.com: Caffeine: How Much Is Too Much?; March 2009
- The Independent: What Alcohol Really Does to Your Body; Peta Bee; November 2005
- "Alcohol Health and Research World;" Alcohol Hangover; R. Swift and D. Davidson
