Hitting the wall

Alistair Brownlee carries his twin brother, Johnny across the finish line. 2016 World Triathlon Championships.

If you have ever “hit the wall”, “bonked” or “ran out of gas” you will understand that feeling when moving becomes conceptual instead of physical. 

At that point, you are done. Nothing is going to make moving easier or less uncomfortable. 

We know that training makes your muscles better at burning fat for energy and lengthens the time you can go before you hit the wall. Some athletes also believe that fat should be the primary fuel source for long distance activity, train your muscles to use fat by eating more fat is the theory. 

It is a theory because, in reality, you don’t work like that. You use glucose, broken down from carbohydrates in foods, and fat for fuel. The more you train the more efficient you are at using glucose.  As your endurance improves, you can access stored fat quicker and use less glucose when compared to someone who isn’t fit, which means you can go further before you run out of gas. However, you still need carbohydrates to be able to burn fat.

New research published in Cell Metabolism now explains what actually happens when you hit the wall. 

Your brain runs out of fuel.

When you hit the wall your brain has run out of glucose. You are done.  Your brain only uses carbohydrates and if you run out, well if you have been there you know how that goes…badly.

Training allows you to use glucose more efficiently, your muscles use less glucose, saving it for your brain and using more fat as a fuel. This is great because even a fit, lean athlete has a lot more stored fat than glucose to use for fuel. The research also discovered a performance enhancing drug that increases the time you can exercise before you run out of fuel. This would be an extreme advantage for those competing in endurance events, but it might also be an advantage for those unable to exercise. That remains to be tested.

I wouldn’t wait for the drug to be available when you can avoid hitting the wall by consuming carbohydrates during endurance activities. It is easier and a lot less painful than hitting the wall.

Change your mind, change your health,


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