Runners' Beans

What happens when you run

Woman running up the stairs to complete her run


Run far, burn calories.  

That's generally about as much thought as we put into energy usage right?  

And, sure, it's not wrong, BUT If you'd like to learn a bit more about what REALLY happens in the body when you run, (wow your friends at dinner parties) then read on below.

Our bodies whether at rest, or while running rely on a good energy supply.  It has three systems to get the energy it needs, and importantly it will ALWAYS use the easiest energy first.  

No prizes for guessing FAT is the last store it will go to for its energy (boo!).   As an aside, while in today's developed world, we probably see this as a flaw, I mean imagine if fat could be the FIRST thing the body burnt for fuell!!  However, our body thinks its doing us a MASSIVE favor, by maintaining fat stores for those times of famine it still thinks exist - it doesn't realise food is only as far as the nearest supermarket for all those living in the developed world.  Thus, the crazy scenario of people starving in one part of the world, while 35% obesity rates in another.  

I digress.  The three systems our body uses are: 

  1. Phosphagen system (use of ATP) - ATP is what your body ACTUALLY uses as energy. You body uses this first, but it only keeps a limited amount of this energy on hand at any given time and is used up fairly quickly...
  2. Glycogen store (use of glucose) - is glucose stored in your body. Your body will use this next because it's far more efficient at being converted to ATP than fat.  Your body keeps enough of this for about 2 hours of use (if you're trained up for a marathon).
  3. Aerobic system (use of fat) -  Fat stores hold a ton of energy in the form of fatty acid chains.  However, it is not easily accessed & only about a third of the energy released can be utitlised.  Our body sees this as stores for a time when food is scarce,  it will be able to break this down slowly to sustain us.  It is not designed as a quick supply because we have decided to go for a very long run.  

N.B. You can see why eating nothing before a run in the hope that 'I'll lose weight as my body burns fat', is a very flawed theory.  This will simply stress the body out and probably cause it to think there is DEFINITELY a famine going on, and hold on even tighter to its fat stores.  Oh, and you will feel horrendous on you run!

running on empty - running fuel required

How long or how hard you run will dictate the extent to which these energy systems last out – most marathoners will have experienced ‘hitting the wall’ at some stage,  when glycogen stores are depleted. It requires oxygen to convert more acetyl sugar to ATP and your lungs aren't efficient enough to grab the oxygen you need.

OK, so now you’ve got a sense as to what goes in with your body during a run, you probably see why its important to fuel your body properly (not just on the day of the run) AND allow your body to recover properly.

IMPORTANT FACT - You are NOT getting stronger or fitter during a run, you are actually breaking your body down during a run. You get stronger and fitter when your body has the time and resources to be able to repair and adapt to what you’ve just put it through.

At Runners' Beans we know real food is the way to fuel your body for running best. However, we also know it can be hard to always get the wide range of food you need for good running nutrition.  That is where a good supplement like Daily Tonic comes in.  All your micronutrient needs are served, meaning your body is at its best to use energy stores properly and to recover effectively.

Running on real food

Finding good sources of glucose pre-run is necessary. We would aim for whole food like dates, rather than a glucose filled processed option.  Dumping straight glucose in the body can cause it's own strain, much better to intake it along with other nutrients such as fibre, or protein.


Check out this blog for some great tips around Running on Real food