As people age, they develop increased body fat and are at increased risk for glucose intolerance, hyperlipidemia, and hypertension. Significant weight loss improves these metabolic complications, but requires prolonged caloric deficit which is difficult and infrequently achieved. Exercise also seems to improve the metabolic complications, but the relative contributions of the specific exercise-induced adaptations and the exercise-induced caloric deficit are known. In this protocol, 12 pairs of obese older (55-70 years) individuals will be matched by weigh, age, sex, and response to glucose tolerance test. After determination of baseline caloric intake, one member of each pair will undergo 6 months of exercise training designed to create a 2,000 kcal/week caloric deficit. The other 12 subjects will restrict their food intake to match the caloric deficit achieved by the individual in the exercise group to whom the food restricted person is matched. Measurements of blood pressure, lipid profiles, and body composition by hydrostatic weighing will be made before and after treatment. Insulin sensitivity and routes of glucose disposal will be measured with an euglycemic hyperinsulinemic clamp combined with indirect calorimetry before and after the 6 months of caloric deficit. With the data collected, the relative contributions of specific exercise-induced adaptations versus the exercise-induced caloric deficit in causing changes in body composition, lipid profiles, blood pressure, routes of glucose disposal, and insulin sensitivity and responsiveness will be determined. This information is important for prescribing therapy and for understanding the mechanism by which exercise improves the metabolic complications of obesity in older individuals.
| Staten, M A; Totty, W G; Kohrt, W M (1989) Measurement of fat distribution by magnetic resonance imaging. Invest Radiol 24:345-9 |
