| Creatine Phosphate is a fuel - it is converted very quickly and the muscles only store tiny amounts (enough for a few seconds only), and creatine is used in recycling ATP as you say. I didn't realise lactic acid was used to provide energy so thanks for mentioning this - having looked it up though, this produces tiny amounts during anaerobic respiration at which time glucose is still the main energy provider. Blood glucose may rise because your body has released stored glucose from the liver, but this takes time - there is a delay between blood sugar levels dropping (due to the intense exercise) and the liver releasing stores and it also takes time for the full aerobic cycle to produce significant quantities of energy and convert that glucose I am most definitely not an expert here so details may be incorrect, but I looked into this when I started running. I was focused on how to maintain energy levels over long distances so may have a different perspective from someone more interested in weight training or other high intensity/short-duration exercise. I found [1] useful as a simple overview of the different energy producing mechanisms, and [2] goes into far more detail than I can readily understand... [1] https://www.acefitness.org/fitness-certifications/ace-answer... [2] https://en.wikipedia.org/wiki/Bioenergetic_systems I would love to see better explanations of how this all works |
I’ve done a full marathon with no fuel (hydration only) in ketosis, pretty awesome and much better than my glucose/gu runs...of course I’ve had some amazing long runs out of ketosis but at certain distances the fueling is a real battle and a battle I’ve lost from time to time. I don’t think there is a good answer for fueling long distances that will work for everyone it’s all about personal experimentation and adaptation.