Column 20, September 2009

Alcohol – The effects of ‘social’ drinking on performance

Many recreational runners look forward to that extra time on Saturday and Sunday mornings when they can pound the pavement or head to their favourite off-road trail. But what happens when the ‘quiet’ night out with friends on Friday and Saturday leads to one too many drinks?

It’s no secret that we are a nation of binge drinkers. In fact one survey found 450,000 adults had drunk beyond the point of intoxication on their last drinking occasion, and 275,000 had set out to get drunk.

And it’s not just the non-athletic or recreational sports population out drinking, there have been many instances in the recent media of even our most elite athletes (non league players included) drinking to the point where either their own or someone else’s health is put at risk.

So what sort of effect does this ‘social’ drinking have on the recreational or elite athlete?

A recent study by Stannard and Barnes at Massey University, found that when recreational sportsmen consumed moderate amounts of alcohol (6-7 standard drinks over 2-3 hours) after strenuous exercise, muscle performance was reduced by almost twice that of those who did not drink.

And this effect was seen up to 3 days after drinking. Another researcher into alcohol and the athlete, Dr Conor O’Brien, supports this finding, saying that “..five or more alcoholic drinks consumed in one night can stay in the body and affect the brain and body activities for up to three days,” in addition he says “two consecutive nights consuming five or more drinks can affect the body for up to five days”.

How does alcohol impair performance?

Alcohol is a diuretic which can cause dehydration and electrolyte imbalances. This will put the athlete at greater risk of muscle tears, strains and cramp, and in severe cases brain impairment, decreased appetite and muscle wasting.

After alcoholic ‘binges’, serum testosterone levels are dramatically reduced, which can result in reduced lean muscle mass, muscle recovery and overall athletic performance.

Reaction times and mental acuity can be impaired for several days, increasing the likelihood of injury, even during a simple run.

Lactic acid breakdown and glycogen resynthesis are delayed, resulting in increased muscle soreness and less energy reserves for the next exercise bout.

The body’s temperature regulation is impaired, which is especially worrying if you are training in hot conditions for greater than an hour.

Injury recovery is prolonged

Immunity is reduced, increasing susceptibility to colds and flus.

Sleep quality and duration is negatively effected

Weight gain can result, due to alcohol’s high caloric content.

*And remember, even if you don’t feel hung over, the lingering effects of alcohol will still hinder performance progress and reduce total work output, meaning a post-drinking run might not help you improve towards you sporting goal.*

What is a safe drinking level in terms of health and sporting performance?

Alcohol tolerance levels vary widely between individuals, and even within the same individual under different circumstances, making it difficult to recommended appropriate drinking levels.

Factors reducing our alcohol tolerance include:

Age - Older and younger people are less able to handle the effects of alcohol

Weight – those below an ‘average’ body weight (ie 60kg for men and 50kg for women)

Infrequent alcohol consumption

Sex – women generally have a lower tolerance

Low body fat levels

Drinking on an empty stomach

The Alcohol Advisory Council (ALAC) of NZ has very general guidelines for safe alcohol consumption based on the ‘standard drink’ (see www.alac.co.nz );

ALAC recommend on any one occasion you should drink no more than:

Six ‘standard’ drinks (men) eg about 6 stubbies/cans of 4% alcohol beer

Four ‘standard’ drinks (women). eg about ½ a bottle of wine

And in any one week, you should drink no more than:

21 standard drinks (men)

14 standard drinks (women)

*However, from recent research it seems that even these levels could be detrimental to sporting performance. And remember, that regardless of any possible benefit of small alcohol intakes to our general health, alcohol will definitely not improve physical performance!.*

So with health AND sport in mind I would suggest:

Avoiding alcohol within 48 hours before a race. Or, if you are used to 1 glass of wine or beer with dinner the night before (such as Olympic Bronze medalist Deena Kastor is), and have not had ill effects, remember to drink extra water to stay hydrated.

Have a high-carbohydrate snack including some lean protein as well as plenty of fluids immediately after a training session, before drinking alcohol.

Have a glass of water after each alcoholic drink

Choose single shots and low-calorie mixers or light beers to reduce both alcohol and caloric consumption

Consume a maximum of 1-2 ‘standard’ drinks (women) or 2-3 (men) in the first hour, then learn to sip slowly. The body can only process around 10g of alcohol (1 ‘standard’ drink) an hour.

To all good things in moderation

Marnie Oberer