Htting the wall/ second wind

Does anyone know the science of why when we "hit the wall" while endurance training, we can get a second wind and have an additional energy surge?

I was cycling today and just ran out of steam about 18 miles (of 24) into my ride. I had to keep going, because it was the only way I could get home. After a few more minutes I got a second wind and was able to ride up a rather steep hill with very little problem at all.

1. I was riding on an empty stomach.
2. I did not consume any calories during my ride, just plain water.
3. I've had this happen before.

Am I burning fat for the energy? Or is it something else that is going on?


  • acpgee
    acpgee Posts: 7,230 Member
    Hitting the wall refers to when your body depletes glycogen stores in muscles. My only experience with this during a 140 km (7 hour) inline skating event was pretty unpleasant. While your body can function on burning fat your brain needs glucose. To me, hitting the wall includes confusion, and lack of coordination as your brain tries to run without glucose.
  • TheRealParisLove
    TheRealParisLove Posts: 1,907 Member
    Hmmm, maybe it was just a gap between using the stored glycogen in the muscles until the liver could release more into the blood stream for extra energy.