Blood sugar, or glucose, is the primary energy source for the body’s cells, fueling everything from physical movement to complex brain function. This glucose is derived directly from the foods and beverages consumed, particularly those containing carbohydrates. The body, primarily through the hormone insulin, works constantly to maintain a tightly regulated balance of glucose in the bloodstream. Maintaining this balance is important because levels that are consistently too high or too low can negatively affect long-term health.
How Test Type Defines the Meaning of 118
The interpretation of a blood sugar reading of 118 milligrams per deciliter (mg/dL) depends entirely on the type of test administered and the timing of the measurement. The most common measurement is the Fasting Plasma Glucose (FPG) test, which requires the patient to have consumed no calories for at least eight hours prior to the blood draw. If 118 mg/dL is the result of an FPG test, it places the reading squarely in the category known as prediabetes, indicating impaired glucose tolerance.
Another scenario is the Random Plasma Glucose (RPG) test, which is taken at any time of the day without regard to the last meal. In this context, a reading of 118 mg/dL is typically considered within a normal, healthy range, as blood sugar naturally spikes after eating. However, even a random reading may prompt a physician to order a follow-up fasting test to establish a true baseline glucose level. A third measurement is the Oral Glucose Tolerance Test (OGTT), which measures blood sugar two hours after consuming a standardized, high-glucose drink. A two-hour reading of 118 mg/dL after an OGTT also falls within the normal range, confirming that the body processed the glucose load effectively.
Clinical Classification of Blood Sugar Levels
Medical professionals rely on standardized thresholds established by major health organizations to classify glucose numbers. These classifications primarily focus on the fasting state, as it provides the most consistent baseline for measuring the body’s ability to regulate glucose. A fasting glucose level below 100 mg/dL is generally classified as Normal Glucose Tolerance, indicating a healthy metabolic state where insulin is efficiently managing blood sugar.
The range of 100 mg/dL to 125 mg/dL is medically defined as Impaired Fasting Glucose (IFG), which is the clinical term for prediabetes. Since a fasting reading of 118 mg/dL falls within this interval, it signifies an elevated baseline glucose level. This elevation means the body is beginning to struggle with either insulin sensitivity or production, although it has not yet reached the disease state.
If the fasting blood sugar measurement reaches 126 mg/dL or higher on two separate occasions, this is the diagnostic threshold for Type 2 Diabetes. This higher level indicates a significant failure in the body’s glucose control system that requires medical management. While 118 mg/dL is not yet diabetes, it is a clear warning sign that the metabolic system is under stress. The healthcare provider may also use the A1C test, which provides an average blood sugar level over the preceding two to three months, to confirm the diagnosis.
Understanding the Health Risks of Prediabetes
The clinical significance of a prediabetic reading like a fasting 118 mg/dL lies in its indication of developing insulin resistance. Insulin resistance is a state where the body’s cells do not respond effectively to the insulin hormone, leaving higher levels of glucose in the bloodstream. Over time, the pancreas attempts to compensate by producing even more insulin, but this effort eventually fails, pushing glucose levels into the diabetic range.
Allowing blood sugar levels to remain in the prediabetic range significantly increases the risk of progression to Type 2 Diabetes Mellitus. Without intervention, many individuals with prediabetes will develop diabetes within a few years, though this progression is not inevitable. Prediabetes is independently linked to an increased likelihood of developing cardiovascular problems.
Chronic, slightly elevated glucose levels damage the lining of blood vessels, contributing to atherosclerosis, which is the hardening and narrowing of arteries. This vascular damage elevates the risk for serious events, including heart attacks and strokes. Individuals with prediabetes have a significantly higher risk of major adverse cardiovascular events compared with those who have normal blood sugar levels. Addressing this condition early is a preventative measure against a wide spectrum of long-term health complications.
Immediate Next Steps and Lifestyle Adjustments
An initial reading of 118 mg/dL, especially if fasting, should prompt an immediate consultation with a healthcare provider to confirm the diagnosis and determine next steps. The physician will likely order a second test, such as a follow-up FPG or an A1C test, to solidify the diagnosis. No single abnormal result is used to diagnose a condition like prediabetes or diabetes.
The most effective path to managing prediabetes begins with targeted lifestyle adjustments. This involves prioritizing whole, unprocessed foods and reducing the intake of refined grains, added sugars, and processed foods. Increasing dietary fiber from vegetables, legumes, and whole grains is also beneficial, as fiber helps to slow the absorption of glucose and improves metabolic health.
Physical activity is a powerful tool for improving insulin sensitivity, allowing cells to utilize glucose more efficiently. A standard recommendation is to aim for at least 150 minutes of moderate-intensity aerobic exercise each week, such as brisk walking. Pairing this aerobic activity with resistance training can enhance muscle mass, which serves as a major site for glucose uptake and storage. Losing 5% to 7% of body weight has been shown to reduce the risk of progressing to Type 2 Diabetes by nearly 60%.