Does alcohol dehydrate you? (excerpt)

Medical News Today
Medically reviewed by Debra Sullivan, Ph.D., MSN, R.N., CNE, COI — Written by Emily Cronkleton on October 28, 2021

Dehydration occurs when the body does not have sufficient amounts of fluid to function effectively. This can cause symptoms such as headache, dizziness, and fatigue. Alcohol has a dehydrating effect on the body, especially when a person consumes it in large quantities.

Severe and untreated dehydration can be life threatening.

Understanding how alcohol affects fluid and electrolyte levels in the body is important for preventing dehydration and maintaining health.

In this article, we describe how alcohol dehydrates the body and provide tips on how to counteract dehydration due to alcohol consumption. We also outline some additional causes of dehydration.

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

Does alcohol cause dehydration?

Dehydration is when the body does not have sufficient amounts of fluid to function effectively. This happens when a person loses more fluids than they take in.

Dehydration can result from using diuretics. These are substances that promote urine production, or diuresis. Alcohol is a diuretic and can therefore cause dehydration.

Symptoms of dehydration

Dehydration can affect multiple bodily functions and cause a wide range of symptoms.

Mild symptoms include:

• thirst
• headache
• dark urine

Moderate to severe symptoms include:

• dizziness
• delirium
• fainting

Without treatment, severe dehydration can cause serious complications, such as:

• electrolyte imbalances
• kidney problems
• shock

Why does alcohol cause dehydration?

Alcohol is a diuretic and therefore causes excessive urination. As a result, a person loses vital fluids and electrolytes.

Some factors that play a role in alcohol-induced dehydration include:

• Drinking alcohol on an empty stomach: Alcohol enters the bloodstream via blood vessels in the tissue lining of the stomach and small intestine. Without food in the stomach, alcohol goes straight into the bloodstream instead of being absorbed more slowly through the stomach and small intestine. As such, drinking on an empty stomach can contribute todehydration.
• Appetite suppression: Large quantities of alcohol can suppress appetite, making a person less likely to eat while drinking. This in turn can speed up alcohol absorption and associated dehydration.
• Kidney function: Drinking alcohol decreases the ability of the kidneys to filter the blood and maintain the balance of fluids and electrolytes in the body. Alcohol also suppressesTrusted Source the release of the antidiuretic hormone vasopressin, which controls how much water the kidneys reabsorb and retain. This reduces fluid retention and increases urination.

The risk of dehydration is greater in older adults and people with chronic conditions, such as:

• diabetes
• cystic fibrosis
• kidney disease

How to counteract alcohol-induced dehydration

To stay hydrated, a person needs to take steps before, during, and after alcohol consumption.

Below are some tips that can help prevent alcohol-induced dehydration:

• Consume alcohol in moderation: The Centers for Disease Control and Prevention (CDC)Trusted Source advise that males drink a maximum of two drinks per day and that females have no more than one drink per day.
• Drink alcohol slowly: It takes the liver 1 hour to process each serving of alcohol.
• Drink water while drinking alcohol: It is advisable to have at least 1 glass of water for each serving of alcohol.
• Drink water regularly: People who forget to drink water regularly can try the following:

• carrying water in a bottle with them
• drinking water on a schedule
• using an app to track their fluid consumption

• Drink other hydrating beverages: In addition to water, a person can consume other hydrating beverages, such as:

• skimmilk
• soy milk
• coconut water
• aloe vera juice
• electrolyte drinks
• herbal teas

• Avoid sugary and caffeinated beverages: These can promote dehydration.
• Eat hydrating foods: Examples of foods with high water content include:

• fruits
• vegetables
• soups and broths

• Avoid fried foods and those high in sodium, protein, and sugar: These foods can promote dehydration.

Other causes of dehydration

There are many other causes of dehydration besides consuming alcohol. They include:

• sweating
• exercise
• hot weather
• low humidity
• high altitude
• vomiting
• diarrhea
• fever

• certain medications, such as:

• diuretics
• laxatives
• medications to controlhigh blood pressure and cardiovascular disease

A person who is already at risk of dehydration from one or more of the above factors should avoid or limit alcohol consumption.