How Does Fasting Affect Blood Glucose Levels?
Blood Glucose and Insulin
Your body needs sugar in your bloodstream, called blood glucose, to survive. Your pancreas produces a hormone called insulin that bonds with the blood glucose. Once the insulin and blood glucose have bonded, they are able to provide your body with a supply of energy. There are several medical conditions that can cause dangerous spikes and dips in your blood glucose levels. A test called a fasting blood glucose test is the best way to determine whether you suffer from one of them.
Causes for Fluctuations in Blood Glucose Levels
Normal blood glucose levels are between 70 mg/dl and 120 mg/dl (milligrams of glucose to deciliters of blood). There are several causes for minor fluctuations within and outside of normal range: eating a meal, strenuous exercise, anxiety or stress and severe illness or disease.
Many of the foods that you eat contain carbohydrates that become blood glucose in your system. After eating a meal, particularly one that is high in carbohydrates or processed sugar, your system is flooded with glucose and your pancreas is unable to produce enough insulin to keep up. Even if you do not suffer from any type of medical condition, it is not uncommon to see your blood glucose level rise to as high as 180 mg/dl during that first hour after a meal. A person with an insulin disorder would see levels higher than 200 mg/dl.
When you exercise, your body has an increased need for energy. During this time, the pancreas produces additional stores of insulin to provide you with that energy. When you stop exercising, your blood glucose levels temporarily rise due to the amount of insulin in your body. When your pancreas stops the additional secretion of insulin, your blood glucose level falls.
Physiology of Insulin Secretion
There are two types of insulin secretion: meal-related and basal. Meal-related insulin secretion is the rapid insulin production that happens after you eat a meal. Any excess blood glucose is stored as fat.
Basal insulin secretion is what happens after your last meal is digested. When you fast, insulin works in conjunction with other hormones to maintain the blood glucose necessary to feed your brain and break down any stored fat to be used as energy.
During exercise, basal insulin secretion falls to allow for an increased supply of energy from your blood glucose.
Fasting
When you fast, your body continues to produce blood glucose from basal insulin secretion. This maintains your body with a steady supply of energy and brain food through the breakdown of those stores of fat. If you are healthy, your blood sugar levels should remain normal until there is not enough stored fat to keep up the supply.
According to the National Institute of Diabetes and Digestive and Kidney Diseases, the blood glucose level of a healthy person should continue to be in the normal range after an eight- to 12-hour fast. A glucose level higher than that can signal a serious medical condition such as type 1 or type 2 diabetes.
Tags: your blood, blood glucose, your blood glucose, blood glucose, glucose level, insulin secretion, your body