Perceptions of exhaustion come on suddenly, and actually impact when the rate of glycogen consumption is relatively slow (compared to the early stages of exercise). However, the body will very quickly pass from a state of relative comfort to one of total discomfort – the dreaded “Bonking”, or Hitting the Wall.
When you hit the wall you have reached the point where the muscle and liver glycogen is suddenly almost depleted and with only fat to maintain blood sugar levels, physical performance level (energy expenditure) has to decline fast. A major aim of sports nutrition products is to maintain blood sugar levels. Unfortunately many of the existing sports drinks and nutrition products can have precisely the opposite effect.
 
How to Avoid “Hitting the Wall”
“Hitting the wall” occurs when exercise is intense enough or lasts long enough to exhaust muscle glycogen and induce hypoglycemia. Athletes who deplete muscle glycogen must take in the right amount of carbohydrates at the right time. Athletes who continuously deplete muscle glycogen must also ingest foods or drinks which deliver a targeted higher glycemic response.
The nutrient intake program designed for endurance athletes, soccer and hockey players, etc. will focus on the control and regulation of muscle glycogen synthesis and resynthesis. Programming your body via your sports drink becomes mandatory in the maintenance of muscle glycogen.
While endurance athletes run the risk of depleting muscle glycogen, non-endurance athletes do not. Non-endurance athletes, like bodybuilders, do not necessarily need to ingest high glycemic carbohydrates during training or while performing. The only time a bodybuilder needs to increase the glycemic index of this carbs is immediately following muscle glycogen depletion. Not all bodybuilders reach that stage, in fact, few ever do during typical training or events. If a bodybuilder has not depleted muscle glycogen and consumes a high glycemic sports drink prior to, during, or following exercise, he will program the carbohydrates/sugars in the sports drink to store in his fat cells! Not a good format for athletes trying to maintain low body fat.
Sprinters and powerlifters, unlike bodybuilders, need to access power very quickly and for only a short period of time. The chemical requirements of a bodybuilder are totally different from that of a sprinter or powerlifter. A surefire way to get random results in training and in competition is to assume that all athletes require the same power output.
Powerlifters, like bodybuilders, during regular training require low glycemic carbohydrates in a sports drink. But when powerlifters attempt to Power Lift, 1 single lift of less than 10 seconds duration, they require high glycemic carbohydrates taken exactly 45 minutes prior to the lift. This is the only time a powerlifter requires a high glycemic response from a drink. Using high glycemic sports drinks or sodas other than as required will insure that the powerlifter has excess body fat and reduced training ability. Since the glycemic response of a sports drink is not common information, and is certainly not provided on the label, the powerlifter may elect to use orange juice as his choice of drink 45 minutes prior to a single lift. In contrast, the bodybuilder will perform at his/her best by sticking to low glycemic drinks prior to, during, and after training and events. High glycemic drinks will bloat the bodybuilder and add adipose tissue fat to his frame.