A Workout a Day Keeps Diabetes Away?
There seems to be a link between obesity and type II diabetes, although it is not clear whether diabetes leads to obesity or vice versa. The GLUT4 transporter is one of many glucose transporters, and it is the one most affected by insulin levels. It is also a protein whose levels can be affected by physical training. Studies have shown that one of the major changes associated with physical activity is an increase in the amount of GLUT4 in the muscle. In the trained state, a person transports more glucose into the cell than when untrained. Studies showed that only one week of moderate exercise (1–2 hours a day at 70% of maximal oxygen uptake) would double the GLUT4 protein content of the muscles of sedentary people.
By definition, loss of function of glucose transport is type II diabetes. The training effect is such that it takes only a few days without training for the activity of GLUT4 to decrease to only half its normal level. Fortunately, the intensity of the training has less to do with the effect, at least in young to middle-aged people. With the apparent link between type II diabetes and obesity, one method of maintaining proper glucose transport appears to be staying light and fit.