Final answer:
Carbohydrate metabolism during exercise involves using both muscle glycogen and gluconeogenesis to supply glucose, with gluconeogenesis providing glucose at a slower rate of 0.2-0.4 grams/minute compared to the skeletal muscles' higher consumption rate of 1-2 grams/minute during exercise.
Step-by-step explanation:
During exercise, carbohydrate metabolism involves several processes to meet the increased energy demands of the body. Initially, muscle glycogen is utilized, following which the blood glucose levels are maintained through hepatic glucose release and gluconeogenesis, the creation of glucose from non-carbohydrate sources. However, the rate at which gluconeogenesis can supply glucose is relatively slow. Specifically, it can only provide glucose at a rate of about 0.2-0.4 grams/minute. This may not be sufficient during high-intensity or prolonged exercise, where muscles can consume glucose at a much higher rate of 1-2 grams/minute. If exercise is extensive, as in several hours at a moderate intensity (i.e., 58% of VO2 max), the individual might experience hypoglycemia, a drop in blood sugar levels that can lead to fatigue and impaired performance.