Under which of the following conditions could an athlete expect performance to begin to suffer if no additional glucose is ingested? a. after 1 hour of moderate-intensity exercise (60% to 85% vo2 max), when blood glucose levels dwindleb. after 1 to 3 hours of continuous moderate-intensity exercise (60% to 85% vo2 max), when glycogen becomes depletedc. after 5 to 6 hours of continuous low-intensity (50% to 60% vo2 max), when blood glucose levels dwindled. after 30 minutes of continuous high-intensity (70% to 90% vo2 max), when glycogen becomes depleted

A. After 1 hour of moderate-intensity exercise (60% to 85% VO2 max), when blood glucose levels dwindle

Explanation:

An athlete  begins to suffer if no additional glucose is ingested after an hour of moderate-intensity exercise (60% to 85% VO2 max), when blood glucose levels dwindle because at that moment hypoglycemia sets in.

Hypoglycemia refers to low amount of glucose in the blood. Cells needed for energetic activities or exercise rely solely on glucose for energy. Therefore when hypoglycemia occurs, there is low amount of insulin (an hormone produced by the pancreas). However, in order to use the glucose, your body needs insulin.  Insulin helps transport glucose into the cells, particularly the muscle cells where they are needed by an athlete to carry out exercises.