The outcome of carbohydrate feeding during exercise on exercise capacity.
Carbohydrate (CHO) is a source of energy for the body and it is broken down into glucose by amylase; it can be stored in two ways, as muscle glycogen or liver glycogen. It is the main source of energy when people participate in moderate-high-intensity exercise which is 70% + of heart rate reserve.
We aimed to discover the effect of CHO consumption immediately before and during exercise on subjects exercise capacity and metabolism rates.
Maughan and Burke (2002) state that prolonged cycling is related to depletion of glycogen in the quadriceps when performed at around 70% of heart rate reserve. This relates to their assumption that the depletion of glycogen in the quadriceps is linked to the exhaustion capacity of athletes. Maughan and Burke (2002) also found that research studies have shown a benefit of CHO intake during extended periods of exercise at high intensity, in cycling however the availability of CHO is not seen as the limiting factor to performance and they believe further research should be done to confirm the effects.
The ingestion of CHO during a period of prolonged exercise is shown to increase exercise capacity and delay fatigue most of the time. Although there are studies that show no effect of CHO feeding for high-intensity exercise such as Clark, Hopkins, Hawley and Burke (2000), and Tsintzas et al who found a reduced muscle glycogen breakdown in cyclist with type I muscle fibers after 60minutes compared to type II muscle fibers which were unaffected.
Green (1991) found that the depletion of endogenous glycogen inhibits an athlete’s ability to sustain prolonged exercise; he also states that the mechanisms of glycogen depletion to fatigue are still hard to define. Where-as Maughan and Burke (2002) state if depleted endogenous stores can be substituted with exogenous CHO then when glycogen stores limits endurance, exercise capacity should be increased....