| Popis: |
Acetone contained in the exhaled air is expected to be an easy noninvasive indicator of lipolysis in our body because acetone is one of the final products in lipolysis. We carried out exercise experiments using two exercise types and three exercise intensities to elucidate the relationship between exhaled acetone and lipolysis induced by exercise. All subjects were healthy men (n=7) who ranged in age from 19-24 years. A bicycle ergometer (cycling) or a treadmill (walking) was used for the exercise. The measurement of V02max to determine exercise intensity for each subject was carried out using a bicycle ergometer. Exercise intensity for a treadmill was determined by comparing the heart rate for both exercise types. For each subject, the exercise intensity was set at 30%, 40%, or 50% of V02max and the duration was 90 minutes in total. Exhaled end-tidal air samples were collected every 15 minutes from 30 minutes before the exercise to 240 minutes after the exercise. Acetone in the sample was analyzed using a FID gas chromatograph. All subjects had a balanced meal (300 kcal) 120 minutes before the exercise and had no meal until the end of the experiment. Exhaled acetone in all experiments kept increasing after the exercise, and however, its increment rates were different by exercise type and exercise intensity. For mild exercise (40% of V02max), there was no significant difference in the increment between cycling and walking. In contrast, for light (30%) and moderate (50%) exercises, the acetone increment in cycling was greater than in walking. For the light exercise, the walking pace might be too slow to induce effective acetone production, and for the moderate exercise, bicycle exercise might induce more glucose depletion and lipolysis in some muscles because cycling was not an ordinary exercise for most subjects. |
