A Visit to the Sports Medicine Clinic
1Rosalind Tanaka, a 13-year-old soccer player, had been feeling out of breath at practice, so her family took her to the sports medicine clinic at Riverside Hospital. Her doctor, Dr. Felix Amankwah, explained that he wanted to see how her body uses food and oxygen. He ordered two tests: a blood glucose test after breakfast and a breath test on a treadmill.
2Dr. Amankwah described a model of what happens to food. In the digestive system, large food molecules are broken down into smaller ones. Starch becomes glucose, a sugar, and proteins become amino acids. The blood carries these small molecules to cells all over the body. Cells can rearrange them to build new large molecules, such as proteins for muscle or glycogen, a stored form of glucose in the liver and muscles. Cells also release energy from glucose through cellular respiration: glucose + oxygen → carbon dioxide + water, releasing energy.
3For the blood test, Rosalind ate nothing overnight. A nurse measured her blood glucose in milligrams per deciliter (mg/dL), and then Rosalind ate toast and a banana. The nurse measured again 30, 60 and 120 minutes later while Rosalind sat and read. Table 2 shows the results.
4For the breath test, Rosalind wore a soft mask connected to a machine that measures how much oxygen she takes in and how much carbon dioxide she breathes out each minute, in liters per minute (L/min). She stood still, then walked, jogged and ran on the treadmill for 4 minutes at each speed, with a short rest between stages. A heart monitor recorded her heart rate. The results for the last minute of each stage are in Table 1.
5Dr. Amankwah told Rosalind that her results were in a healthy range. He suggested that she warm up longer before practice and build up her running time slowly.