Sunday, 6 March 2011

Some number crunching

Let's look at my latest mantra:

500,000 steps, 20,000 cals, 145 miles, 45 hours, 2 feet...let's beat Prostate Cancer

Let's look at this incredible figure of 20,000 calories and see how I got to that number.

The numbers

The general rule of thumb for a runner is that we use 100-140 calories per mile when training and racing, I have always assumed I burn about 140 calories per mile . These figures are confirmed by my running buddy Mr K in his excellent blog
The running life and times of Mr K Mr K mentions that he burns approximately 140 calories per mile (figures from his Garmin) which stands true as the two of us are of similar stature.

Let's do the numbers
Simple calculation

Number of miles x Calories per mile = Total Calories required
145 x 140 = 20,300 calories

Divide that by 3,100 (number of BMR Calories I need per day to survive) and it comes to the amazing figure which is the the equivalent of 6.5 days worth of calories to be consumed in just 2 days!!!


  1. Jerry if you ever stop running and continued the calorie intake you would explode.

  2. Just to make matters worse: don't forget that human bodies cannot metabolise more than 280 kcal per hour when exercising. That works out at 13440 kcal in 48 hours. Not enough.

    Most runners can't manage 240 kcal per hour so be very careful.

    And then there's the electrolytes to think about ...

    Sorry, all the best though in the GUCR. I am a bit jealous as that race is on my 'to do' list. Maybe next year.

  3. Thanks Chris
    This post caused a bit of a flurry on Twitter and various places due to this "rule of thumb" maths.
    I think we can safely say that I will not be running all the way as there will be a lot of walking and there will certainly be some fat stores amongst other things burnt up during the way; there will obviously be my store to take into consideration which will make the numbers a little better.
    What will be interesting to do is to take a before and after weight measurement.

    As for electrolytes, I am beginning to think about that after The Ridgeway when I was really getting dehydrated but I am on top of that now...I think.

  4. Re: Hydration, I am sure there are quite a few pubs along the GUCR route.......