Glucose Fasting(FPG)

The diagnostic threshold for type 2 diabetes is a fasting glucose of 126 mg/dL or higher on two occasions, with the prediabetic range running 100 to 125 mg/dL. For longevity-focused men, however, the optimal target sits meaningfully below the prediabetic threshold. Observational data link fasting glucose values above roughly 95 mg/dL with elevated all-cause mortality, dementia risk, and cardiovascular events even in patients who never meet diagnostic criteria for diabetes. A single fasting glucose can be misleading in three common scenarios. The first is the dawn phenomenon, where overnight growth hormone and cortisol drive hepatic glucose output and produce a high fasting reading despite excellent postprandial control. The second is acute stress, infection, or strenuous exercise within the prior 24 hours, all of which transiently elevate the number. The third is reactive hypoglycemia, where a normal fasting glucose hides large postprandial swings best detected by a continuous glucose monitor or a 2-hour oral glucose tolerance test. For most men a fasting glucose under 90 mg/dL combined with a fasting insulin under 7 mIU/L is a reasonable optimization target, with the understanding that the underlying signal of interest is whole-day glucose stability rather than any single morning value.