Can alcohol affect sports performance?

• Effects of alcohol on sport performance
• Exercising the day after the night before
• Longer-term effects
• Alcohol and your heart rate
• Drinking alcohol while recovering from a sports injury
• Cutting back

It doesn’t matter whether you’re a casual exerciser, are in the gym every day, or compete in regular matches or events, anyone who cares about playing sport or keeping fit should understand the effects alcohol can have on their performance. Not having a balanced approach to alcohol could be what gets in the way of you reaping the rewards from all the work you've put in.

Figures from Sport England show that more people are taking part in sport than they used to. In December 2011, Nearly 7 million adults played some kind of sport three times a week for 30 minutes – over 100,000 more than in 2007 (1). At the same time, latest figures from the NHS show that nearly two in five men (35%) and just under a third (28%) of women had drunk above the daily unit guidelines on at least one day in the past week (2). So we’re getting more active but is this move to a healthier lifestyle counteracted by our alcohol consumption?

Effects of alcohol on sport performance

Overall, alcohol is detrimental to sports performance because of how it affects the body during exercise. It does this in two main ways.

Firstly, because alcohol is a diuretic, which means it makes your kidney produce more urine, drinking too much of it can lead to dehydration. Exercising soon after drinking alcohol can make this dehydration worse because you sweat as your body temperature rises. Combined, sweating and the diuretic effect of exercise make dehydration much more likely. You need to be hydrated when you exercise to maintain the flow of blood through your body, which is essential for circulating oxygen and nutrients to your muscles. “Dehydration leads to reduced performance," says Professor Greg Whyte, an expert in sports performance who trained comedian David Walliams in his cross English Channel swim for Sport Relief. “Hydration also helps control your body temperature so you’re more likely to overheat if you’ve been drinking alcohol.”

Secondly, alcohol interferes with the way your body makes energy. When you’re metabolising or breaking down alcohol the liver can’t produce as much glucose, which means you have low levels of blood sugar. Exercise requires high levels of sugar to give you energy. If your liver isn’t producing enough glucose, your performance will be adversely affected. “If your body is forced to run from your supplies of fat rather than blood sugar, you will be slower and have less energy and won’t be able to exercise as intensely,” says Professor Whyte. As a result, your coordination, dexterity, concentration and reactions could be adversely affected too.

Both of these effects are immediate which is why it’s not advised to exercise or compete in sport soon after drinking alcohol.

Exercising the day after the night before

Drinking alcohol the night before could have a negative influence on your performance the following day. Sports dietician Jane Griffin says, “it’s not possible to perform at your best if you’re feeling any of the effects normally associated with a hangover such as dehydration, a headache and hypersensitivity to outside stimuli such as light and sound”.

Trying to avoid a hangover? Get some simple tips here

Even if you’re not experiencing the symptoms of a hangover, elite sports nutritionist Matt Lovall adds that “exercising the day after drinking alcohol can mean you have an all round lower quality training session or sporting activity.

You’ll lack strength and power, be less likely to make split second decisions and more likely to feel tired quicker because your body won’t be able to clear out the lactic acid you produce when you exercise. “This is because your liver will be working harder to get rid of the toxic by-products of alcohol in your system,” explains Lovall.

For all of these reasons, experts suggest avoiding alcohol the night before exercise whether you’re due to go for a heavy session at the gym or compete in a team game. However, if you do decide to drink, both Lovall and Griffin advise sticking to just one drink with food. 

“I would say with whether you have a drink the day before a training session or workout – you make the choice. But definitely think twice before drinking the day before a competition or match, ” says Griffin.

Similarly, drinking after exercise is not advisable if you haven’t consumed enough water to replace the fluids you lost. Professor Whyte recommends sticking to the unit guidelines and alternating with soft drinks. He warns that having a greater amount than this after exercise is more likely to make you crave stodgy high in calorie foods – which could affect your sports performance later down the line if you put on weight as a result. Drinking too much and eating calorific food will cancel out the health gains of the exercise your body would have benefited from.

Longer-term effects

Indeed, alcohol is high in sugar which means it contains lots of calories – seven calories a gram in fact, almost as many as pure fat. “If your aim in the gym or through exercise is weight management, then it seems paradoxical to consume ‘empty’ calories in liquid form,” says Professor Whyte. Alcohol can also slow down the amount of calories you’re able to burn through exercise. Because your body isn’t designed to store alcohol, it tries to expel it as quickly as possible. This gets in the way of other processes, including absorbing nutrients in food and burning fat.

Muscle gain can be affected too. Alcohol can disrupt sleep patterns and growth hormones, vital for muscle growth, are released while you're in deep sleep. It could also reduce the amount of testosterone – a hormone you need to gain muscles – you have in your blood. “And drinking alcohol to excess can poison muscle fibres which means they don’t adapt like they should do for up to three days,” says Lovall.

Alcohol and your heart rate

Most worryingly, drinking can increase the potential for unusual heart rhythms. This is a risk which significantly increases during exercise up to two days after heavy alcohol consumption. “How much you need to drink to be at risk depends on the individual, but the risk increases if you are an irregular drinker,” says Professor Whyte. It’s because the activity itself already increases your heart rate and with a lot of alcohol in your system, you put extra stress on the organ. Other long-term impacts of alcohol such as heart disease, cancer and liver disease, could stop you taking part in exercise and sport altogether. 

Drinking alcohol while recovering from a sports injury

Sports performance is also impaired when you drink after you’ve had an injury. You’ll be out of action for longer because the recovery process slows down. “It’s difficult to quantify how much you have to drink but we know that alcohol causes the blood vessels to the skin, arms and legs to open up,” explains Griffin. “The increased blood supply makes an injury bleed and swell even more.”

Cutting back

If you regularly drink above the government’s daily unit guidelines your body starts to build up a tolerance to alcohol. This is one of the main reasons why it’s important to not regularly exceed the guidelines and to consider having regular alcohol-free days. If you are drinking above the guidelines, see what positive results you notice when you reduce your drinking – better sports performance is likely to be one of them.

Keep track of how many calories you are consuming in your favourite drinks using our tool MyDrinkaware which includes a unit calculator.