Quote:
Originally Posted by REDLAN  .... The body's total glycogen supply is around 45 minutes running at 85% MHR (or thereabouts) - after this the individual becomes exhausted and is no longer able to maintain the intensity. ..... If you are on insulin failing to replenish your glycogen reserves can have fatal consequences. .... |
I have had difficulty finding useful information on glycogen. So correct me if I am wrong, and I would be interested in looking at other sources. But from what I can make out, the liver stores 100-120 grams of glycogen, which it keeps topped up all the time. If you don't eat carbs, glucose from gluconeogenesis is used for this purpose. So failure to replenish these reserves by eating carbs is of no real consequence. One might expect to see a loss of muscle in the long term, but this is not borne out by actual experience.
Twice as much glycogen is stored in the muscles as is stored in the liver (200-240 grams of glycogen). By cycling glycogen depletion/replenishment, bodybuilders increase their glycogen reserves by another 50+%. Muscle glycogen is used mainly during intense cardio work (85+% of VOX2max) and resistance exercise. Apparently, because of the lack of an enzyme, muscle glycogen can only be used in the muscles it is stored in. So this glycogen can't be can't be used to deal with a hypo anyway. And failure to replenish it will only compromise physical performance.
So a well conditioned athlete should be carrying 360+grams of glycogen, or 1,440+ calories worth. On its own, this would fuel 2 hours of fairly intense activity. You also have about 80 grams of glucose in the bloodstream that. But even when working close to maximum aerobic capacity, a third of calories will still come from fat. And you would only expect to exhaust glycogen reserves after, say, 3 hours?
