Unfortunately there are a number of ways that alcohol can hamper your training gains and impair your sports performance:

Metabolism and fat loss

  • When your body takes on alcohol it has no way of storing those calories as an energy source. It must therefore prioritise the metabolism of alcohol which consequently restricts the use of fat and carbohydrates as a fuel source. They will instead be stored for later use.
  • Alcohol causes a release of insulin that increases the metabolism of glycogen. This will again spare your existing fat from being used as an energy source making fat loss more difficult.
  • It increases the levels of cortisol within the body. A high cortisol level encourages fat storage.
  • Alcohol interferes with the metabolism of protein and fat in the liver and causes an impaired production of pancreatic enzymes that are required for fat metabolism, making it more difficult to control your levels of body fat.

Exercise performance

There are detrimental effects on exercise performance capacity. Alcohol consumption has a negative effect on your energy supply. It impairs the metabolic process during exercise by decreasing the use of glucose and amino acids by muscle tissue. This makes it harder to work at higher levels of intensity. When you have alcohol in your bloodstream it will feel as if you are working just as hard to reach only a moderate intensity as you would on days when you are feeling fresh and ‘in the zone’. Your rate of perceived exertion (RPE) will be altered.

Other negative side effects on sports performance include

      • Reduced muscular endurance, power and strength
      • Impaired balance
      • Reduced accuracy
      • Slower cognitive function (tactical decision making processes)
      • Slower reaction times

Nutrient deficiency

Alcohol irritates the lining of the stomach having a detrimental effect on the absorption and utilisation of vitamins and minerals. Many of these are catalysts for the processing of carbohydrates and protein needed for energy and muscle repair.


Alcohol is of course responsible for dehydration. Just ask anyone who’s woken up with a banging headache following a drink or two the night before. The negative effects of dehydration are explained in more detail in our exercise and hydration article.


You need to be well rested to perform at your optimum. Alcohol consumption reduces muscle recovery by disrupting your sleep pattern; the optimal time your body repairs itself after a training session. Muscles require human growth hormone release and a disrupted sleep cycle can reduce your output by as much as 70%. Research has shown that alcohol in the bloodstream can decrease not only sleep duration, but the overall quality of sleep. 

Overall health

If you’re feeling run down, drinking alcohol is likely to exacerbate the problem. It will impair your defences and weaken the strength of your immune system making you more prone to illness and therefore likely to have to miss out on some of your training.

Alcohol and exercise

Of course, as with most things moderation is the key and there’s no harm in the odd drink. But the choice is yours; if you have specific training or fat loss goals you are trying to achieve it’s worth remembering all of the above. An athlete who is tired and hungover can’t perform at their best.

© Hillcliff Personal Training 2012


Hillcliffalcohol and exercise