Effects Of Alcohol On The Body

This article explores the short and long-term  impact of consuming alcohol as well as alcohol safety tips to drink in moderation.


Short-term effects of alcohol include drowsiness, poor coordination, increased heart rate, dehydration, and memory loss, while long-term effects can include damage to the pancreas, heart, liver, nervous system, and brain. Difficulty in weight management and interpersonal relationships are also at risk from heavy drinking. Further details into these health risks, what level of alcohol consumption is dangerous, and tips to avoid them are discussed in this article.

What are the effects of alcohol on the body?

Drinkers can experience both positive and negative short-term effects from alcohol consumption, however, the long-term  effects of alcohol on the body are harmful. The long and short-term  effects of alcohol on the body are  linked to the quantity of alcohol consumed.

According to the NHS, one alcohol unit is equal to 10ml of pure alcohol, which is how much alcohol an average person can process in an hour.1 The number of alcohol units in a drink is based on its size and strength. For example, a shot of spirits (ABV 40%) is approximately 1 unit, while a standard-sized glass of wine is approximately 2.1 units.1 

Short term effects of alcohol

Some of the short-term effects of alcohol on the body include drowsiness, nausea, poor coordination, increased heart rate, dehydration, and memory loss.2 Individuals with a high tolerance for alcohol may be able to drink more heavily without experiencing these effects.1 Furthermore, alcohol amount and frequency of alcohol consumed within a given time frame impact  the body's  response.1 

1 to 2 units: Consuming 1 to 2 units of alcohol leads to an increased heart rate and blood vessel expansion, which creates the social, and positive feelings associated with alcohol.2

4 to 6 units: When consuming 4 to 6 units, which is classified as binge drinking, the drinker's impacted nervous system, and brain lead to an inhibited judgement which encourages reckless behaviour.2 It is also common to feel light-headed and experience poor reaction times and coordination.2

8 to 9 units: After consuming 8 to 9 units of alcohol, the drinker's coordination will be severely impacted, and begin to experience alcohol’s depressant effect, leading to drowsiness.2 The body will attempt to remove the alcohol from the system through excessive urination, which can cause dehydration and headaches the morning after.2 This level of alcohol can also disrupt digestion, leading to diarrhoea, vomiting, nausea, and indigestion.2 

12 or more units: Consuming 12 or more units puts the drinker at risk of alcohol poisoning.2

Long term effects of alcohol

Alcohol consumption can have many long-term effects on health with one study finding alcohol to be the leading worldwide risk factor for disability and death.3 The pancreas, heart, liver, nervous system, and brain are all impacted by long-term alcohol abuse.2 Long-term heavy drinkers may experience increased blood pressure and cholesterol levels, which can be risk factors for cardiovascular disease, heart attacks, and strokes.2 Liver, mouth, breast, bowel, head, and neck cancer are also potential long-term  risks from alcohol misuse, with cancer due to alcohol consumption being the top cause of death in older adults, according to one study.2,3 For example, the cancer risk from alcohol increases even when the patient has small quantities of alcohol (fewer than 1 drink).4 

Alcohol can also have a significant impact on mental health. Heavy drinking has been linked to depression, with hangovers leading to people feeling anxiety, especially when they experienced a blackout the night before.5 Sleep patterns, judgement, and behaviour can also be disrupted.5 It has also been shown that long-term alcohol consumption can lead to the frontal lobe shrinking.3

Alcohol is also high in calories, which means its excessive and long-term consumption can lead to weight gain. For example, the standard glass of wine contains 133 calories, and a pint of 5% ABV beer is approximately 239 calories.6 A one-off drink is not too many calories, but when a person has multiple drinks in one evening a couple of nights a week, the calories can easily add up. People are also tempted to eat unhealthy junk food after a night of heavy drinking, which adds further excess calories.

Alcohol’s physical effects on the body

Circulatory system: High blood pressure, stroke, and heart attacks are potential risks.2 Women have an even greater risk of heart disease than men.3 Another potential risk is heavy drinking leading to an enlarged heart that cannot be reversed.5 

Reproductive system: Sexual dysfunction can occur in men, such as premature ejaculation or impotence.2 Infertility is also a risk due to inhibited hormones; for example, in women, menstruation may be impacted.3

Digestive system: Alcohol can lead to salivary gland damage, oesophagal  ulcers, internal bleeding, stomach ulcers and gastritis, haemorrhoids, gum disease, and tooth decay.3j Drinkers can also become malnourished due to difficulties in nutrient absorption. 

Central nervous system: As well as impacting behaviour, alcohol can also impair speaking, impulse control, and coordination.3 Heavy drinkers may experience ‘blackouts’ and be unable to make memories.3 Other potential impacts on the central nervous system are weakness, numbness, and temporary paralysis.3

Immune system: Your immune system can also be compromised, which leaves the person at risk for infections.4 

Excretory system: The pancreas can lose its insulin production capabilities and be damaged.3 Pancreatitis is also a risk.2 Excessive alcohol can also lead to liver damage and alcoholic fatty liver disease, which can lead to jaundice, hepatitis, and cirrhosis.3 Further health effects on the excretory system are bladder, kidney, and prostate inflammation.4

Skeletal system: Bones can also be weakened by long-term alcohol consumption, making the person at risk for breaks and osteoporosis.4

Risk factors of alcohol use

Depending on the level of drinking, alcohol use can have various risk factors. 

Moderate drinking

is defined as a consumption of 1-2 drinks per day for men and 1 drink per day for women.4 However, two out of three adults have reported drinking more than this amount at least once a month.4 There are many risks associated with moderate drinking, according to the NHS, more than 1 out of 10 visits to accident and emergency departments are alcohol-related  illnesses.2 This includes accidents caused by loss of coordination and judgement, as well as violent behaviour and unprotected sex while intoxicated, which can lead to violent incidents, the transmission of sexually transmitted infections, and unintended pregnancies.2

While past studies have suggested that moderate drinking can offer health benefits, more recent studies have disputed this claim.4 In fact, a 2018 study found that the current recommendation for moderate drinking has too great impact on health and that a lower recommendation would be more appropriate.3 

Excessive drinking

Binge drinking is defined as consuming 4 or more alcoholic beverages for women, and 5 or more for men, during a single occasion.2 Excessive drinking can result in alcohol poisoning, which can affect your breathing, gag reflex, and heart rate and can lead to death in severe cases.2 The risk of short-term health effects and long-term chronic issues also increases when drinking beyond moderate drinking recommendations.4,7 Alcohol misuse can also have long-term social implications beyond health, such as domestic abuse, homelessness, financial difficulty, and unemployment.2 Excessive alcohol consumption can also lead to alcohol dependency with the drinker even experiencing alcohol withdrawal symptoms in severe cases.

Standard drink

Having a rare standard drink should not lead to the risks discussed previously. One 2018 study found that adults who participated in light drinking (1-4 drinks per week) had a lower risk of death compared to those who consumed no alcohol.7 However, another study that looked at the overall health impact of alcohol, including cancer, cardiovascular diseases, car accidents, and infectious diseases, found that the healthiest option was no alcohol consumption.7 Therefore, it is difficult to give a conclusive answer about the positive effects of alcohol on the body, and further alcohol research is required.

Alcohol safety tips

It is recommended that adults should limit their alcohol intake to 2 drinks or less per day for men, and 1 drink or less per day for women.4 Certain groups of people, such as pregnant women, underage individuals, those with medical conditions, or taking certain medications, and those with a history alcohol abuse, should not drink at all. Alcohol addiction treatment, alcoholics Anonymous , and rehab are options for those who struggle with alcoholism.

When drinking alcohol, it is important to pace oneself, be aware of the number of units consumed, and recognize the signs of alcohol poisoning. Drinking smaller-sized or lower-strength alcoholic beverages, avoiding alcohol on an empty stomach, and alternating between alcoholic and non-alcoholic beverages are recommended. It is also important to avoid driving or operating heavy machinery after drinking alcohol and to have a designated driver or access to a ride service. 

If alcohol poisoning is suspected, it is recommended to call for an ambulance and to place the affected person on their side with a cushion under their head. An unconscious person suspected of alcohol poisoning should not be left to sleep, as their blood alcohol levels can continue to rise for up to 30 minutes after their last drink. Signs of alcohol poisoning to look out for include unconsciousness, seizures, slow breathing, vomiting, confusion, cold, and clammy or pale skin.2


Drinking alcohol can be a great way to spend time with friends and celebrate; however, excessive consumption can bring on numerous negative health effects in the short and long term. It is important to know how to pace yourself, be aware of the risks, and be prepared to call for help if someone showcases symptoms of alcohol poisoning.

Due to the debate around alcohol offering health benefits and the varied scientific evidence, the best recommendation would be to have little to no alcohol in your diet to reduce the negative health effects as much as possible. One can be teetotal to remove the health risks however, this could negatively impact one's quality of life. It is important to consider the positive effects alcohol has, as it can increase social interaction, be part of traditions or celebrations, and is a fun recreational activity for many people. It is not realistic for many adults to have an alcohol-free lifestyle, so encouraging them to drink in moderation is still the best guideline.


  1. Alcohol units [Internet]. nhs.uk. 2022 [cited 2023 Feb 17]. Available from: https://www.nhs.uk/live-well/alcohol-advice/calculating-alcohol-units/
  2. Drinking too much alcohol can harm your health. Learn the facts | CDC [Internet]. 2022 [cited 2023 Feb 17]. Available from: https://www.cdc.gov/alcohol/fact-sheets/alcohol-use.htm
  3. Facts about moderate drinking | CDC [Internet]. 2022 [cited 2023 Feb 17]. Available from: https://www.cdc.gov/alcohol/fact-sheets/moderate-drinking.htm
  4. Robert S. Alcohol and your health: Is none better than a little? [Internet]. Harvard Health. [cited 2023 Feb 17]. Available from: https://www.health.harvard.edu/blog/alcohol-and-your-health-is-none-better-than-a-little-2018091914796
  5. Barbara A. 7 Things Drinking Alcohol Does to Your Body [Internet]. Cone Health. Available from: https://www.conehealth.com/services/behavioral-health/7-things-drinking-alcohol-does-to-your-body/
  6. Tips on cutting down [Internet]. nhs.uk. 2022 [cited 2023 Feb 17]. Available from: https://www.nhs.uk/live-well/alcohol-advice/tips-on-cutting-down-alcohol/
  7. Calories in alcohol [Internet]. nhs.uk. 2022 [cited 2023 Feb 17]. Available from: https://www.nhs.uk/live-well/alcohol-advice/calories-in-alcohol/
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Christina Weir

Master of Science - MS, Biotechnology, Bioprocessing & Business Management, University of Warwick

Hey there, I'm Christina (Krysia), and I'm thrilled to be an article writer for Klarity! I recently completed my master's degree in Biotechnology from the University of Warwick, and currently, I work at The Francis Crick Institute in Science Operations. I love being involved with the institute's exciting biomedical research and have a passion for Science Communications. My goal is to simplify science so everyone can join in and learn something new!

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