This piece is filed under rules of running. Why? Because I need to know how much beer is 2.5km worth. And I reckoned many of you would be interested to know, if only to justify that pint.
Craft beer after a run, ‘liquid gold’ as a triathlete friend puts it
For a long time, I have set an arbitrary rule that I allow myself half a pint of beer for every 2.5km I run in a week. I have shared this rule with some of my friends, Harpreet being one of them. This morning I wrote a reply to another friend, who complained that in one of her runs this week, she struggled to run more than 2.5km, when she had been doing twice that distance regularly. I mentioned this rule but qualified that it was not empirical and it was just my reckoning.
So I thought why not try find an empirical solution? So here it is. How much beer is 2.5km run worth answered.
The premise is that we spend energy when we run., Kcal being the measure for energy. When we eat or drink, we are actually taking in energy. Energy in foods or drinks are also measured in kcal. So if we know how much energy we expend while running 2.5km and know how much energy is in a pint of beer, then we can easily calculate how much beer is 2.5km worth.
First we look at the input side of the beer/run equation. How many calories are in a pint of beer? Different styles of beer, because of the amount of barley, malt and hops will have slightly different amount of calories. Here we shall look at 3 styles, bitters, stouts and craft beer. For bitters and stouts, we shall use the British standard pints and for craft beer we shall use the 12 US Oz bottles as standard measure. Beers contain anywhere between 28 to 35 kcal per 100ml. Stout contains 170 kcal, while bitters contains 180 kcal.
Nutritional Content of 3 styles of beer. Sources: http://www.fermentedlychallenged.com/2008/08/truth-about-calories-and-beer.html & http://www.weightlossresources.co.uk/calories/calorie_counter/alcohol.htm
Without attempting to explain in detail the physics and biochemistry of the energy equation we shall now look at the expend side of the beer/ run equation. We shall use what tools that are available to us. There are many tools and calculators available to calculate a person’s energy expenditure. All of them use Basal Metabolic Rate (BMR) and Metabolic Equivalent of Tasks (MET). The Harris Benedict equation is the equation used to measure BMR while MET is simply the ratio that expresses energy expenditure as a multiple of BMR. Variables for calculating BMR and MET are the body’s ability to use Oxygen (VO2), weight, height and age of the person. So according to the person’s size, energy expenditure while running will vary.
Here the tool I used is the energy expenditure calculator tool on https://www.polarpersonaltrainer.com. This is my training tracker tool that works with my Polar running computer. Using my profile of VO2, height, weight and age, the energy expenditure calculator, gave me 7.3 kcal per minute at 60%-70% HR zone and 9.5 kcal per minute at 70%-80% HR zone. By assuming that I run 10km at 6min 30s pace, which is 60-70% HR zone I can calculate the energy I spent when running 2.5km.
Results are then as follows:
My beer vs 2.5km calculator
The conclusion then is that my arbitrary rule of a half pint of beer being worth a 2.5km is a slight underestimate. Empirically, every 2.5km I run, I can afford myself 0.6 pint of bitters or stout or 0.7, 12US oz bottle of craft beer.
I can calculate your beer/ run ratio for you, just shout out.
Enjoy your run and your beer!
Stone Delicious IPA