An A1c of 5.7% is not dangerous, but it is a warning sign. It sits right at the bottom edge of the prediabetes range (5.7% to 6.4%), which means your average blood sugar over the past two to three months has been higher than normal. The good news: this is the earliest possible stage where prediabetes is detected, and it’s highly reversible with lifestyle changes.
What 5.7% Actually Means
The A1c test measures the percentage of your red blood cells that have sugar attached to them. Because red blood cells live for about three months, the test captures a rolling average rather than a single snapshot. An A1c of 5.7% translates to an estimated average blood glucose of about 117 mg/dL, using the standard conversion formula. For reference, a normal fasting blood sugar is under 100 mg/dL.
The American Diabetes Association defines the ranges like this:
- Below 5.7%: Normal
- 5.7% to 6.4%: Prediabetes
- 6.5% or higher: Diabetes
At 5.7%, you’re at the very start of the prediabetes window. Your body is beginning to have trouble processing sugar efficiently, but you haven’t crossed into diabetic territory. Think of it less as a diagnosis and more as an early alert system doing its job.
The Health Risks at This Level
Prediabetes isn’t just about eventually developing type 2 diabetes. A large meta-analysis published in The BMJ found that people with A1c levels in the 5.7% to 6.4% range already had an increased risk of cardiovascular events and coronary heart disease compared to people with normal blood sugar. The risk is modest at 5.7%, but it’s measurably there.
The more immediate concern is progression. Without changes, roughly 15% to 30% of people with prediabetes develop type 2 diabetes within five years. The higher your A1c climbs within the prediabetic range, the steeper that risk becomes. Catching it at 5.7% gives you the widest possible window to act.
Your A1c Might Not Be Perfectly Accurate
A few biological factors can push your A1c reading higher or lower than your actual blood sugar warrants. The most common culprit is hemoglobin variants, which are inherited differences in the structure of your red blood cells. Variants like hemoglobin S (associated with sickle cell trait), hemoglobin C, and hemoglobin E can interfere with certain A1c testing methods. These variants are more common in people with ancestors from Africa, South and Southeast Asia, and the Mediterranean region.
Conditions that affect red blood cell lifespan can also skew results. Iron-deficiency anemia, for example, tends to falsely raise A1c because red blood cells live longer and accumulate more sugar. Pregnancy, recent blood loss, or blood transfusions can push the number in either direction. If your result feels inconsistent with your other blood work or your overall health picture, a fructosamine test or a glucose tolerance test can provide a second opinion.
How Much Lifestyle Changes Actually Help
This is where the data gets genuinely encouraging. The landmark Diabetes Prevention Program, tracked by the CDC, found that people who lost 5% to 7% of their body weight and exercised at least 150 minutes per week reduced their risk of developing type 2 diabetes by 58%. For people over 60, the reduction was even more dramatic: 71%. Even 15 years later, participants who made lifestyle changes still had a 27% lower incidence of diabetes compared to the control group.
For someone weighing 200 pounds, 5% to 7% weight loss means losing 10 to 14 pounds. That’s a realistic, non-extreme goal. The 150 minutes of weekly exercise breaks down to about 30 minutes of brisk walking five days a week.
The specific changes that move the needle most:
- Reducing refined carbohydrates: White bread, sugary drinks, and processed snacks cause the sharpest blood sugar spikes.
- Adding fiber and protein to meals: Both slow down how quickly sugar enters your bloodstream after eating.
- Consistent moderate exercise: Walking, cycling, or swimming improve your body’s ability to use insulin effectively, even before you lose significant weight.
- Modest weight loss: Even small reductions in body fat, especially around the midsection, improve insulin sensitivity.
How Long It Takes to See Results
Because A1c reflects a two-to-three-month average, you won’t see changes overnight. If you start making meaningful adjustments to your diet and activity level today, your next A1c test in three months should reflect some improvement. Most people see a noticeable drop within two to three testing cycles, so roughly three to six months of sustained effort.
The American Diabetes Association recommends that anyone with prediabetes get their A1c retested at least once a year. Your doctor may suggest testing every three to six months initially, especially if you’re actively working to bring the number down, so you can track your progress and stay motivated.
Where 5.7% Sits in the Bigger Picture
An A1c of 5.7% is the mildest form of prediabetes. It’s not an emergency, and it’s not a diabetes diagnosis. But it does mean your metabolism is heading in a direction you want to correct. People who ignore prediabetes and maintain the same habits tend to see their numbers creep upward over time. People who take it seriously often bring their A1c back below 5.7% and keep it there for years.
The fact that you’re searching for this information puts you in a better position than most. About 80% of people with prediabetes don’t know they have it. Knowing your number, and knowing it early, is exactly the advantage that makes prediabetes one of the most preventable progressions in medicine.