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, drinking too much can lead to dehydration because the alcohol makes your kidney produce more urine. 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. “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.