As treatment, you tell Joe that the best thing he can do is to avoid strenuous exercise. If he does wish to exercise, you advise him to consume sports drinks containing glucose or fructose frequently while exercising. Why would this help alleviate Joe’s suffering during exercise?
The correct answer and explanation is:
Correct Answer:
Consuming glucose or fructose during exercise helps provide an alternative energy source to compensate for Joe’s impaired ability to use fat for energy.
Explanation:
Joe’s condition likely involves a metabolic disorder affecting his ability to use fats for energy. Normally, during prolonged or strenuous exercise, the body shifts from using glucose to burning fat through a process called beta-oxidation. In metabolic disorders such as Medium-Chain Acyl-CoA Dehydrogenase Deficiency (MCADD) or other fatty acid oxidation disorders, the body cannot properly break down fat for energy. This leads to low blood sugar levels (hypoglycemia) and a lack of energy during periods of increased energy demand like exercise.
By avoiding strenuous exercise, Joe can reduce the energy demands on his muscles and prevent his body from relying heavily on fat metabolism. However, if Joe chooses to engage in physical activity, supplying his body with glucose or fructose through sports drinks gives his muscles an immediate and usable energy source. Glucose is absorbed directly into the bloodstream and taken up by cells for energy via glycolysis. Fructose is also converted to glucose in the liver or used in glycolysis.
Frequent consumption of these simple sugars during exercise helps maintain blood glucose levels, preventing hypoglycemia and supplying energy that Joe’s body cannot efficiently generate from fat. This reduces fatigue, prevents muscle breakdown, and lowers the risk of more severe complications such as lethargy or unconsciousness that can occur with metabolic crises. Additionally, by sparing the use of fat as a fuel source, Joe avoids the buildup of toxic metabolic intermediates that could worsen his symptoms. Hence, sports drinks with glucose or fructose offer a practical and preventive approach during physical activity for individuals with fat metabolism disorders.