Originally Posted by
Iride01
I can tell the difference in whether I'm drinking water or drinking a mix with carbohydrates. If you are riding at a hard HR zone 4 and 5 pace for a while, then when you take that gulp or two of mix, you'll feel the energy coming back within 60 to 90 seconds. And back when I was using fructose/sucrose carbs, the surge in energy didn't last as long. With the maltodextrin that I use now, it seems to be a more steady release of energy that I feel longer between gulps from the bottle. Somewhat seems reasonable as fructose and sucrose are simple sugars where as maltodextrin is considered a complex carb.
If you are only a HR zone 2 and 3 rider, then you may not ever get enough energy deficit to notice.
There is a reproducible positive effect of simply tasting a sweet solution (and spitting it out) on performance, so immediate effects are likely mediated by the nervous system effectively taking the brakes off in anticipation of the actual metabolic effect.
I think 60-90 seconds is an underestimate for real fueling, since we're talking about gut transport, passage from the capillary circulation of the gut back through the venous system, right heart, lungs and left heart, muscle uptake, and glycolysis, but it's measured in minutes.