In healthy people, skeletal muscles are highly sensitive to insulin. They can increase glucose uptake with sudden increases in blood glucose levels to keep the blood glucose levels within normal.
As people age, skeletal muscles undergo wear-and-tear and acquire more damage. Skeletal muscles become increasingly resistant to insulin, and elderly people progressively lose the ability to keep their glucose levels within the normal range, eventually leading to diabetes.
Another factor that directly affects glucose metabolism is having a sedentary lifestyle. Generally, older people are less active than their young counterparts.
Studies have shown that having a sedentary lifestyle, particularly sitting or lying down over long periods of time, can lead to changes in the body’s metabolism. This includes a decline in insulin sensitivity, which then results in increased blood glucose levels and eventually, Type 2 diabetes. It is therefore recommended that an active lifestyle, in concurrence with dietary changes, must be promoted among the elderly.
An important aspect in the development of Type 2 diabetes among the elderly is associated with beta-cell destruction. Insulin is synthesized in and secreted by beta cells located in the pancreas. In normal, healthy adults, the beta cells secrete insulin in direct proportion to the glucose levels in the bloodstream. That is, when glucose levels rise above the normal range, the body will send a signal to the beta cells to produce more insulin to help absorb glucose.
However, with age, beta-cell function declines, and in turn, the amount of insulin released in the body decreases. This leads to dysregulated glucose levels in the bloodstream and eventually, diabetes.