Compensatory hyperinsulinaemia
Chronically high insulin levels, produced when the pancreas works overtime to keep glucose normal. The hidden middle of insulin resistance.
Compensatory hyperinsulinaemia is the state of chronically elevated insulin in the blood. The word "compensatory" is the key: the high insulin is the body compensating for cells that respond sluggishly to it.
When cells become insulin resistant, the pancreas releases more insulin to get the same job done. For years, sometimes decades, this keeps blood glucose in the normal range. Glucose looks fine while insulin runs high in the background.
This is why insulin resistance is so easy to miss. A standard fasting glucose test only sees the end stage, when the pancreas can no longer keep up and glucose finally rises. The earlier, hidden phase is the high insulin doing the compensating, which is why fasting insulin or HOMA-IR catches what glucose alone does not.