According to a study from the University of Miami in 2009, heavy drinkers are often heavy exercisers, with the boozers doing an extra 20 minutes of hard exercise a week compared to their teetotal buddies.
But does drinking alcohol actually affect your performance? Bad news folks; here’s why booze isn’t the best idea if you’re a runner.
1. Alcohol causes dehydration
It's well known that running dehydrates you, so it's important to drink lots of water. But drinking alcohol has the same effect! Consuming alcohol causes your kidneys to produce more urine, so you go to the loo more often, causing dehydration. Being dehydrated when you run puts you at risk of cramps and muscle strain, plus increasing feelings of fatigue.
2. Alcohol lowers your blood sugar levels
If you've ever craved sweet stuff after a boozy night, you'll know what we're talking about. When you drink alcohol, your body reacts to it as a toxin and starts putting all its energy into getting rid of it.
To do that, it interrupts other processes, including the process of glucose conversion and the production of the hormones needed to regulate it.
When you’re running, you need your blood sugar to be on an even keel and your glucose supplies to be high, as this is the primary source of energy for exercise, so having a few drinks in the days leading up to a big run is likely to affect your performance.
3. Alcohol is full of empty calories
If you're trying to lose weight – or even if you're not – it's important to know that alcohol contains a staggering seven calories per gram. And because alcohol is high in sugar, it's more likely to settle around your middle, causing that dreaded 'beer belly'.
One study, published in the Journal of Nutrition, examined whether various drinking patterns differentially effect fat distribution, particularly abdominal fat in women and men. Over a period of time, the study found that those who drank daily may be the same weight as a non-drinker, but they added inches to their waistlines.
4. Alcohol interrupts your sleep
Getting a good night's sleep is vital to staying on top of your game, but drinking more than one or two units a day will start to leave you feeling exhausted.
While the Government's unit guidelines state there’s no safe level of alcohol consumption, they advise not to regularly drink more than 14 units per week, and definitely not all in one go.
Trying to sleep after you've been drinking alcohol causes you to go straight into a deep sleep, missing out on the first stage of sleep - rapid eye movement (REM) sleep. But then the alcohol wears off and you return to REM, which is lighter and easier to wake up from, which is why you often conk out, only to wake a few hours later.
A night or two of disrupted sleep is enough to throw your sleep cycle off, which can take days to recover, leaving you feeling more and more tired.
5. Alcohol stunts muscle growth
Alcohol has a bad effect on muscle growth, too. Drinking too much can interfere with protein synthesis – this is the process where the muscle cells generate new proteins, essential for recovery and growth. Without this, we wouldn't improve and be constantly at risk of injury.
6. Alcohol causes an irregular heart rate
Having a few glasses causes not only cause your heart rate to increase, but also your blood pressure, which can be particularly problematic for those with an underlying problem. If you're then working out or hitting the running hard, you're increasing your risk of a heart attack or stroke.
7. Alcohol slows recovery
Alcohol can increase bleeding and swelling through a vasodilatory effect (i.e. increased blood supply to blood vessels). The liver helps the body recover from exercise and is also responsible for dealing with alcohol, but it cannot do both things well enough at the same time – so recovery suffers.