What are the dangers of excessive alcohol drinking

Drinking too much – on a single occasion or over time – can take a serious toll on your health.  Here’s how alcohol can affect your body:

Brain:
Alcohol interferes with the brain’s communication pathways, and can affect the way the brain looks and works. These disruptions can change mood and behavior, and make it harder to think clearly and move with coordination.  

Heart:
Drinking a lot over a long time or too much on a single occasion can damage the heart, causing problems including:

• Cardiomyopathy – Stretching and drooping of heart muscle
• Arrhythmias – Irregular heart beat
• Stroke
• High blood pressure  

Liver:
Heavy drinking takes a toll on the liver, and can lead to a variety of problems and liver inflammations including:

• Steatosis, or fatty liver
• Alcoholic hepatitis
• Fibrosis
• Cirrhosis

Pancreas:
Alcohol causes the pancreas to produce toxic substances that can eventually lead to pancreatitis, a dangerous inflammation and swelling of the blood vessels in the pancreas that prevents proper digestion. 

Cancer:
According to the National Cancer Institute: "There is a strong scientific consensus that alcohol drinking can cause several types of cancer. In its Report on Carcinogens, the National Toxicology Program of the US Department of Health and Human Services lists consumption of alcoholic beverages as a known human carcinogen.

"The evidence indicates that the more alcohol a person drinks–particularly the more alcohol a person drinks regularly over time–the higher his or her risk of developing an alcohol-associated cancer. Even those who have no more than one drink per day and people who binge drink (those who consume 4 or more drinks for women and 5 or more drinks for men in one sitting) have a modestly increased risk of some cancers. Based on data from 2009, an estimated 3.5% of cancer deaths in the United States (about 19,500 deaths were alcohol related."

Clear patterns have emerged between alcohol consumption and increased risks of certain types of cancer:

• Head and neck cancer, including oral cavity, pharynx, and larynx cancers.

• Esophageal cancer, particularly esophageal squamous cell carcinoma. In addition, people who inherit a deficiency in an enzyme that metabolizes alcohol have been found to have substantially increased risks of esophageal squamous cell carcinoma if they consume alcohol.

• Breast cancer: Studies have consistently found an increased risk of breast cancer in women with increasing alcohol intake. Women who consume about 1 drink per day have a 5 to 9 percent higher chance of developing breast cancer than women who do not drink at all.

For more information about alcohol and cancer, please visit the National Cancer Institute's webpage "Alcohol and Cancer Risk" (last accessed October 21, 2021).

Immune System:
Drinking too much can weaken your immune system, making your body a much easier target for disease.  Chronic drinkers are more liable to contract diseases like pneumonia and tuberculosis than people who do not drink too much.  Drinking a lot on a single occasion slows your body’s ability to ward off infections – even up to 24 hours after getting drunk.

For more information about alcohol's effects on the body, please visit the Interactive Body feature on NIAAA's College Drinking Prevention website.

Celebrating at parties, cheering a favorite sports team, and enjoying get-togethers after work are common ways to relax or be with friends. For some people, these occasions may also include drinking—even binge or high-intensity drinking. And when that happens, the results can be deadly.

Drinking too much and too quickly can lead to significant impairments in motor coordination, decision-making, impulse control, and other functions, increasing the risk of harm. Continuing to drink despite clear signs of significant impairments can result in an alcohol overdose.

What Is an Alcohol Overdose?

An alcohol overdose occurs when there is so much alcohol in the bloodstream that areas of the brain controlling basic life-support functions—such as breathing, heart rate, and temperature control—begin to shut down. Symptoms of alcohol overdose include mental confusion, difficulty remaining conscious, vomiting, seizure, trouble breathing, slow heart rate, clammy skin, dulled responses such as no gag reflex (which prevents choking), and extremely low body temperature. Alcohol overdose can lead to permanent brain damage or death.

What tips the balance from drinking that produces impairment to drinking that puts one’s life in jeopardy varies among individuals. Age, sensitivity to alcohol (tolerance), gender, speed of drinking, medications you are taking, and amount of food eaten can all be factors.

Alcohol use and taking opioids or sedative-hypnotics, such as sleep and anti-anxiety medications, can increase your risk of an overdose. Examples of these medications include sleep aids such as zolpidem and eszopiclone, and benzodiazepines such as diazepam and alprazolam. Even drinking alcohol while taking over-the-counter antihistamines can be dangerous. Using alcohol with opioid pain relievers such as oxycodone and morphine or illicit opioids such as heroin is also a very dangerous combination. Like alcohol, these drugs suppress areas in the brain that control vital functions such as breathing. Ingesting alcohol and other drugs together intensifies their individual effects and could produce an overdose with even moderate amounts of alcohol.

Anyone who consumes too much alcohol too quickly may be in danger of an alcohol overdose. This is especially true of individuals who engage in binge drinking, defined as a pattern of drinking that brings blood alcohol concentration (BAC) to 0.08 percent or higher,* typically occurring after a woman consumes 4 drinks or a man consumes 5 drinks in about 2 hours;1 as well as high-intensity drinking, defined as drinking two or more times the binge-drinking thresholds for women and men.2

Teenagers and young adults who drink may be at particular risk for alcohol overdose. Research shows that teens and college-age young adults often engage in binge drinking and high-intensity drinking. Drinking such large quantities of alcohol can overwhelm the body’s ability to break down and clear alcohol from the bloodstream. This leads to rapid increases in BAC and significantly impairs brain and other bodily functions.

*A blood alcohol concentration (BAC) of 0.08 percent corresponds to 0.08 grams per deciliter, or 0.08 grams per 100 milliliters.

As BAC Increases—So Do the Risks

As blood alcohol concentration (BAC) increases, so does the effect of alcohol—as well as the risk of harm. Even small increases in BAC can decrease motor coordination, make a person feel sick, and cloud judgment. This can increase an individual’s risk of being injured from falls or car crashes, experiencing acts of violence, and engaging in unprotected or unintended sex. When BAC reaches high levels, blackouts (gaps in memory), loss of consciousness (passing out), and death can occur.

BAC can continue to rise even when a person stops drinking or is unconscious. Alcohol in the stomach and intestine continues to enter the bloodstream and circulate throughout the body.

It is dangerous to assume that an unconscious person will be fine by sleeping it off. One potential danger of alcohol overdose is choking on one’s own vomit. Alcohol at very high levels can hinder signals in the brain that control automatic responses such as the gag reflex. With no gag reflex, a person who drinks to the point of passing out is in danger of choking on his or her vomit and dying from a lack of oxygen (i.e., asphyxiation). Even if the person survives, an alcohol overdose like this can lead to long-lasting brain damage.

• Mental confusion, stupor
• Difficulty remaining conscious, or inability to wake up
• Vomiting
• Seizures
• Slow breathing (fewer than 8 breaths per minute)
• Irregular breathing (10 seconds or more between breaths)
• Slow heart rate
• Clammy skin
• Dulled responses, such as no gag reflex (which prevents choking)
• Extremely low body temperature, bluish skin color, or paleness

Know the Danger Signs and Act Quickly

Know the danger signals and, if you suspect that someone has an alcohol overdose, call 911 for help immediately. Do not wait for the person to have all the symptoms, and be aware that a person who has passed out can die. Don’t play doctor—cold showers, hot coffee, and walking do not reverse the effects of alcohol overdose and could actually make things worse.

While waiting for medical help to arrive:

• Be prepared to provide information to the responders, including the type and amount of alcohol the person drank; other drugs he or she took, if known; and any health information that you know about the person, such as medications currently taking, allergies to medications, and any existing health conditions.

• Do not leave an intoxicated person alone, as he or she is at risk of getting injured from falling or choking. Keep the person on the ground in a sitting or partially upright position rather than in a chair.

• Help a person who is vomiting. Have him or her lean forward to prevent choking. If a person is unconscious or lying down, roll him or her onto one side with an ear toward the ground to prevent choking.     

Stay alert to keep your friends and family safe. And remember—you can avoid the risk of an alcohol overdose by staying within the 2021-2025 Dietary Guidelines for Americans if you choose to drink, or by not drinking at all.

For more information, please visit: https://www.niaaa.nih.gov

1National Institute on Alcohol Abuse and Alcoholism. NIAAA Council approves definition of binge drinking. NIAAA Newsletter, No. 3, Winter 2004. https://pubs.niaaa.nih.gov/publications/Newsletter/winter2004/Newsletter_Number3.pdf. Accessed September 5, 2018.

2 Hingson, R.W.; Zha, W.; and White, A.M. Drinking beyond the binge threshold: Predictors, consequences, and changes in the U.S. American Journal of Preventive Medicine 52(6):717–727, 2017. PMID: 28526355