Devon hard at work in the Bergman laboratory
Drs. Bryan Bergman and Leigh Perreault are recruiting volunteers for an insulin resistance and exercise study being performed at the University of Colorado Denver. The issue under investigation is the correlation between muscle fat and insulin resistance in professional athletes as compared to us normal folks. Insulin resistance refers to the loss of the ability of insulin to do its job, moving sugar out of the blood. Fat molecules are not only found in fat cells. Since they are a form of stored fuel they can be found in all cells including muscle. Insulin resistance is indicative of pre-diabetes. “It is when our patients are in the pre-diabetic state, before the onset of full blown diabetes, that we have the best chance of helping them,” stated Dr Perreault.
Researchers have known for some time that in non-athletes, the amount of muscle fat correlates very well with insulin resistance. The more fat in the muscle cells, the less the body responds to insulin. However, when one looks at a trained athlete one sees the exact opposite. Athletes have a large store of muscle fat and they are very sensitive to insulin.
“Therein lays the paradox” stated Dr. Perreault. “This is important because skeletal muscle is the primary tissue involved in insulin resistance.”
Skeletal muscle is the more specialized term for what we think of as muscle – the tissue that gives us strength. The other type of muscle is smooth muscle and includes the heart and the muscle that contracts blood vessels and maintains blood pressure.
“One way that this could make sense is for us to consider the time that the fat remains in the muscle,” indicated Dr Bergman, the principle investigator of this study. Athletes have a lot of muscle fat but they are constantly exercising and are constantly burning it up. Conversely, in non-athletes, the residence time of the fat in that muscle cell should be considerably longer.
The study will test this by comparing 3 groups; overweight patients with diabetes, non-diabetic overweight patients, and trained athletes. Each person will rest for 4 hours, exercise for 90 minutes at a specific intensity, and then recover for 2 hours. Muscle biopsies will be taken and analyzed for fat content and turnover.
Understanding how insulin sensitivity works is of crucial importance in the fight to slow the onset of type II diabetes. Increased sensitivity to insulin means lower blood glucose and less stress on the pancreas. Additionally, lower blood glucose means less damage to tissues over the years. While we know that exercise improves things, we still do not have the details. This study will be another step forward along that path of understanding.
The study is still recruiting volunteers. A detailed description of the study groups needed can be found here. To volunteer, call Devon Hunerdosse at 303-724-3968.
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