Two Bouts of Exercise before Meals, but Not after Meals, Lower Fasting Blood Glucose Levels says scientists in the August 2009 issue of Medicine & Science in Sports & Exercise.
Participants were nine healthy postmenopausal women who were given two hours of treadmill exercise at 43% of their maximum effort twice a day and 1 hour before a meal.
They conclude that the Before-Meals exercise, but not After-Meals exercise, reduced glucose levels by 20%. And there was a 49% increase in insulin-glucagon ratio during meals.
The nutrient-regulated control of the release of insulin and glucagon manages metabolism and blood levels of glucose, fatty acids, triglycerides and amino acids. These are responsible for homeostasis; the minute-to-minute regulation of metabolism leading to a stable inner milieu. The mechanisms involved are extremely complex. Yet, unfortunately these are still not completely understood.
After a meal, fat from food is stored and carbohydrates from the diet are burned. Between meals stored fat is released from fat cells and supplies fuel for most of the body’s organs until the next meal. Blood cells and the brain must use glucose as their energy source. We say that “fat spares sugar” so that an even supply of fuel is available to all of the body’s tissues. This is possible only through the minute-to-minute adjustments in the ratio of insulin to glucagon.
These results demonstrate that exercise performed in postabsorptive,( Before meals) but not in postprandial ( After meals ) state, lowers the fasting blood glucose levels.
Also sustained lowering of blood glucose are most likely the consequences of reduced carbohydrate availability during exercise.
