Tom Martens

When you exercise your body burns fuel in 3 stages.

Phase one:

For the first few minutes your body will utilize an Anaerobic pathway (no oxygen) that is quick to respond but is very inefficient. Creatine Phosphate and Glycogen which is stored in your muscles and liver cells gets used first. As much as 20% of the total Glycogen that is stored there can be used during this phase.

Phase two:

There will be a shift in metabolism to the more efficient Aerobic pathway (oxygen) where the energy stored in fat cells is used. This phase creates much more heat. This phase lasts the longest or until the stored energy in your fat cells is depleted.

Phase three:

As the exercise intensifies or is prolonged there is a switch back to anaerobic energy use using up the remaining stored Glycogen.It is during this phase that one of the by-products of the Anaerobic pathway- Lactic Acid is produced. Lactic Acid is what makes your muscles sore after heavy, prolonged exercise.

After learning this information I started thinking about many years ago remembering a funny feeling I would get after I would start running. After about the first 3 or 4 minutes of running I would get this feeling that started in my legs and worked its way up to my torso that felt like lightly burning goose bumps! It only lasted for 10 seconds or so but I never knew what was causing it. Now I know it was the switch from phase 1 pathway to phase 2 pathway.

I’ve since changed my running style to the “Galloway” running style for marathons. My style based on my running speed equates to running 5 minutes and walking 1 minute- the whole race. This minimizes the build up of lactic acid and also minimized that weird goose bump feeling so much that I don’t notice it anymore.