How alcohol affects your body

Ever wondered what the effects of drinking alcohol are? We all know alcohol holds back performance, but do you know exactly what’s going on in your mind and body as a result of drinking? Lucy-Ann Prideaux reports…

We explain how alcohol affects your body. Credit: valentinrussanov/Getty

Despite our best intentions it’s hard to avoid the lure of alcohol. Whether it’s socially down the pub or to unwind at home after a hard week at work, many of us find it hard to resist ‘just one more wine’. 


For triathletes, the over-eating part isn’t so much of a problem – it can quite easily be shifted when you start the obligatory  detox/weight-loss programme. But the drinking can pose a much bigger problem to not only your short-term training regime but also your long-term health. 

To see the full picture, it’s necessary to understand the chemical make-up of alcohol, how the body deals with it, and its effect on organs and functions of the body.

What are you drinking?  

Ethyl alcohol is the chemical we know as ‘alcohol’. It’s absorbed from the stomach and small intestine and distributed throughout the system via the bloodstream. Over 90% of alcohol that enters the body is oxidised to acetic acid, a metabolic process that occurs primarily in the liver. Being a toxin it also affects a large number of organs and biological processes along its way. 

Evidence shows that regular consumption of too much alcohol leads to increased risk of diabetes, liver disease, bone loss, coronary heart disease and, in women, breast cancer. Even ‘minor’ health complaints such as eczema, hormone imbalances and nervous complaints can often be linked to regular alcohol consumption. 

The digestive system bears much of the brunt of drinking alcohol, and regular consumption can lead to both minor and serious digestive complaints. Being an irritant, alcohol can inflame the stomach lining and small intestine, reduce the absorption of nutrients, stimulate the secretion of acidic gastric juices and, if heavy drinking persists, can lead to stomach ulcers, diarrhoea and vomiting. 

Regular drinking also changes our appetite, perceptions and choices around food, and disrupts blood-sugar (glucose) levels and control, which can lead to cravings for sweet, starchy or high GI foods. For the athlete, this could mean making poor carbohydrate choices, resulting in energy highs and lows. Levels of blood glucose ideally need to be kept steady throughout the day to keep energy levels up, control the appetite and boost concentration.

Alcohol vs sport

The main concerns surrounding regular drinking and physical training are the risks of chronic dehydration, blood-sugar imbalances, and impeding your body’s ability to absorb necessary nutrients and deplete vitamins already stored. 

Because alcohol is a diuretic, urine output increases with consumption, which not only causes the dehydration but also leads to the loss of water-soluble nutrients (B vitamins), minerals (magnesium and zinc) and vitamin C. Alcohol also suppresses the immune system, which reduces the body’s chance of adapting to training stresses. Although alcohol provides energy, unlike carbohydrate calories, calories from alcohol cannot be metabolised or stored in the muscles.

How a person reacts to training and performs after drinking the previous night really depends on the severity of the drinking episode and how they, as an individual, detoxify alcohol. But as well as chronic thirst and energy loss, other symptoms can include:

Toxicity – nausea, overheating (alcohol impairs your body’s ability to regulate body heat), headache and dizziness. 

Slower reaction times and reduced coordination and balance.

Loss of endurance, strength and speed.

Increased risk of injury. 

Slower respiratory system.

Interrupted sleep patterns.

Contrary to popular belief it’s not possible to sweat alcohol out of the body, as alcohol is primarily detoxified in the liver at a rate of approximately one unit every hour. And no, you can’t speed this up by sitting in the sauna for hours or doing a mammoth training session. Both are futile measures which only serve to increase the already dehydrated
state of the body. 

If you’ve only consumed 1-2 single units, continue training as normal the following day, or do a light session. But your digestive system ideally needs at least 48 hours to recover following heavy drinking.

How much does alcohol affect race performance?

What’s safe? 

Drinking 3-4 units for men and approximately 2-3 units a day for women is considered ‘safe’ according to the UK’s Department of Health. A unit is a 125ml glass of wine, a single measure of spirits, a ¼ pint of strong lager, cider or ale, or ½ pint of ‘regular’ strength. Bear in mind that the ‘safe’ amount is not something to aim for or justify reaching! Remember also that we all have a different tolerance and capacity to detoxify alcohol, and what is a tolerable amount for one may be too much for another. Even drinking up to the recommended ‘safe’ amount can lead to health problems. 

Similarly, drinking vast amounts at once is not healthy. This pattern of drinking – often termed ‘binge drinking’ – can cause stomach and pancreatic inflammation, and has been linked to the increase in certain cancers.

  Small measures

To reduce the effects of alcohol, introduce fresh fruit (strawberries, raspberries, cherries), vegetables (green leafy salads and green vegetables), eggs and fish into your diet before and after you drink. And, of course, drink plenty of water.

When you’re out, ensure that you drink a glass or a small bottle of water for each alcoholic drink. This is likely to lead to a lower intake of alcohol and less severe dehydration. Before bed, drink a large glass of plain water to offset dehydration, which is the main culprit behind a hangover. Natural yoghurt is also good for balancing blood-sugar levels before sleep, while a good vitamin B complex and 500mg of vitamin C will replenish lost vitamins.

The day after the night before, drink plain water. Eat a wholegrain honey and banana sandwich, porridge or plain oats with sliced banana and honey – all of which contain the necessary carbs and sugars, B vitamins and mineral salts to replenish the body. 

Ultimately we’re not monks, so key is to ensure that you’re fully recovered and rehydrated before you start training again. If necessary, rest for a full 48hrs. And just make sure that those end-of-week drinks don’t turn into a daily occurrence. 

Choose wisely

Not all alcohol is bad for you. Drunk in moderation, the following beverages actually have some health benefits…

Red wine
Contains protective flavonoids and antioxidants. One to two glasses a day is also thought to reduce the risk of heart disease and may help protect against certain cancers.

Organic wines
Some organic wines are lower in artificial preservatives such as sulphites, which can cause allergic reactions in some people. 

Guinness is high in iron, as well as containing antioxidant compounds similar to those found in fruits and veg. However, like beer, stout is relatively high in calories. 

Contains vitamin B6, which prevents the build-up in the body of a chemical called homocysteine, which is linked to an increased risk of heart disease.


Note: the least calorific alcoholic drinks include bottled light or alcohol-free beers (18-25 kcals per 250ml), a single measure of vodka or gin with soda and fresh lime (48 calories), a 125ml glass of dry white wine (82 calories), or a 125ml glass of red wine (85 calories). Wine spritzers are also a good choice as they’re less dehydrating due to the water.