Blood glucose, or blood sugar, is the primary source of energy for the body’s cells, derived from the food consumed. The body maintains this sugar within a narrow range, and a fasting blood glucose (FPG) test measures this regulation after an overnight fast of at least eight hours. A result of 105 milligrams per deciliter (mg/dL) is not a diagnosis of diabetes, but it signals that the body’s process for managing blood sugar is beginning to struggle.
Interpreting the Fasting Blood Glucose Range
A fasting blood glucose reading of 105 mg/dL falls outside the range considered optimal for metabolic health. Standard medical guidelines define a normal FPG level as anything below 100 mg/dL, indicating the body effectively clears sugar from the bloodstream during the fasting period.
The 105 mg/dL result places the reading within the category known as Impaired Fasting Glucose (IFG), often referred to as prediabetes. This diagnostic window ranges from 100 mg/dL up to 125 mg/dL. A result in this range signifies insulin resistance, meaning the body is producing insulin, but the cells are not responding to it efficiently.
This reading is a warning sign, not a full medical crisis. A diagnosis of diabetes is not made until the FPG level is 126 mg/dL or higher, typically confirmed on two separate tests. Therefore, 105 mg/dL indicates an elevated risk that requires attention before it progresses.
Key Factors That Influence Glucose Levels
The slightly elevated reading of 105 mg/dL often stems from a gradual decrease in the body’s sensitivity to insulin, known as insulin resistance. This means that liver, muscle, and fat cells do not easily take up glucose from the blood, forcing the pancreas to produce excessive insulin to compensate. Over time, the pancreas may become exhausted, allowing fasting glucose levels to climb into the IFG range.
Dietary habits play a significant role, particularly the regular consumption of refined carbohydrates and sugars. Rapidly digested foods cause a sharp spike in blood glucose, triggering a large insulin release that contributes to desensitization. A lack of physical activity further compounds this issue, as muscle contraction during exercise helps draw glucose out of the blood independent of insulin, improving overall sensitivity.
Non-dietary factors, including acute physiological stress, can also temporarily push readings higher. Stress hormones like cortisol and adrenaline raise blood sugar to provide immediate energy. When this hormonal state is sustained, it interferes with overnight glucose regulation, resulting in an elevated FPG reading. Certain medications, such as some steroids, can also elevate glucose levels.
Necessary Follow-Up and Lifestyle Adjustments
The most important next step after a 105 mg/dL FPG result is to consult with a healthcare provider for follow-up testing and evaluation. The physician will likely recommend a retest of the FPG to confirm the result and may also order an A1C test. The A1C test measures the average percentage of blood sugar attached to hemoglobin over the previous two to three months, offering a more complete picture than a single-day fasting test.
This FPG result serves as an opportunity for proactive intervention, as lifestyle modifications have been shown to reverse Impaired Fasting Glucose. A primary goal is weight management; studies demonstrate that a modest weight loss of 5% to 7% of total body weight can significantly reduce the risk of progression. This weight reduction improves insulin sensitivity, making the body’s cells more receptive to the hormone.
Physical activity is another powerful tool, with a goal of at least 150 minutes of moderate-intensity aerobic exercise per week, such as brisk walking. Nutritional focus should shift toward consuming more high-fiber foods, including whole grains, fruits, and vegetables, while reducing the intake of processed foods and sugar-sweetened beverages. These changes slow the rate at which sugar enters the bloodstream and are an effective strategy for bringing the FPG level back into the optimal range.