Can You Lower Your A1C Overnight? How Long It Takes

You may be familiar with the A1C test and its use for diagnosing type 2 diabetes and monitoring blood sugar levels over the past three months. 

The A1C test, also called the hemoglobin A1C test, was first recommended by the American Diabetes Association (ADA) for use in the 1980s and is now a routine laboratory value.

It measures how much glucose is attached to the hemoglobin in your blood.

On average, hemoglobin regenerates every 120 days and reflects how much glucose has been floating in your blood. 

A1C is an excellent marker for tracking glycemic control and giving patients and healthcare professionals a larger snapshot of how your body manages glucose levels. 

Let’s dive in and discuss if it’s possible to lower A1C overnight and tips for lowering your A1C levels quickly and effectively. 

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Can You Lower Your A1C Levels Overnight?

Unfortunately, no, you cannot lower your A1C levels overnight. The nature of the test is that it measures the average amount of glucose in your blood over the last 120 days.

One day of lower blood glucose levels will not lower your A1c levels when compared to the other 119 days of blood glucose levels.

Day by day, better glucose control will improve the A1C result. 

Finger pricks to check your present glucose levels will give you immediate feedback on how your body handles food, lifestyle changes, and exercise. 

How Long Does It Take to Lower A1C Levels?

Glucose levels in the most recent six weeks will have a greater impact on the A1C level than glucose levels in the previous six weeks.

So, an effort to manage glucose levels for six weeks should result in a lower A1C level. 

The most accurate time to see if your changes have lowered your A1C levels is after at least three months of effort.

Most of the hemoglobin and attached glucose will reflect your new lifestyle.  

How to Lower A1C Quickly

The following lifestyle factors help lower your A1C quickly.

These strategies lower your daily glucose levels and, over time, reduce your A1C level. 

Diet Changes

Adopting a lower carbohydrate diet reduces A1C significantly after three months.

Carbohydrates include grains, breads, pasta, rice, fruit, milk, starchy vegetables, beans, sugar-containing drinks, and foods.

Low- or very-low-carbohydrate diets, like ketogenic diets (ranging from 21 to 70 g/day of carbohydrates), are restrictive and more challenging to maintain long-term, resulting in lower A1C. 

Because low-carbohydrate or very low-carbohydrate diets result in ketosis, these plans are not suitable for some patients with type 2 diabetes, including women who are pregnant or lactating, people with or at risk for eating disorders, or people with renal disease. 

Moreover, due to the increased risk of diabetic ketoacidosis (DKA), patients taking certain medications, such as SGLT-2 inhibitors, should avoid very low-carbohydrate/ketogenic diets.

Many dietitians recommend eating three balanced meals, which include a moderate amount of carbohydrates plus protein and healthy fats.

This eating style is less restrictive and effectively lowers A1C. 

Moderate carbohydrate diets (30 to 65% of calories from carbohydrates) have been well studied, reducing A1C with a more sustainable and realistic eating pattern. 

Research shows a 0.8% reduction in A1C after five weeks following a 40% carbohydrate/30% protein/30% fat diet.

The ADA recommends working with a registered dietitian to individualize your diet and achieve glycemic control. 

Hydration

Hydration is important for many reasons, including accurate blood glucose monitoring and A1C results. 

Dehydration can increase blood sugar levels because less water is in the blood, resulting in more concentrated glucose. Staying hydrated prevents inaccurate test results. 

Hydrate with unsweetened beverages and water to prevent added sugar that could elevate your blood glucose and A1C. 

Exercise

Exercise lowers glucose available in the blood and helps reduce A1C levels, along with other health benefits, such as fewer heart disease events. 

A randomized controlled trial involved 262 sedentary adults with type 2 diabetes and A1C levels of 6.5% or higher who were enrolled in a nine-month exercise program. 

Participants were randomized to aerobic exercise (walking or jogging), resistance training (weights), or a combination of both exercises. Individuals in the combination group reduced their A1C by 0.34% on average.

This study was one of the first on sedentary individuals with type 2 diabetes.

Another large randomized trial reports that resistance training among people with type 2 diabetes improves A1C by 0.57%. 

The ADA recommends at least 150 minutes per week of aerobic exercise and two resistance training sessions to improve glycemic control. 

Of note, a decrease of 1% in A1C has been associated with a 15 to 20% decrease in major heart disease events and a 37% decrease in microvascular (artery) complications. 

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What Do My AIC Results Mean?

A1C is a percentage of your red blood cells with sugar-coated hemoglobin.

The higher the percentage, the higher your glucose levels have been. 

The test is often a finger prick or a draw from your arm. Your A1C results determine whether you are in the normal range or at risk for complications due to elevated blood glucose levels.

For individuals managing diabetes, a target is an A1C of less than 7%.

An A1C level is sometimes reported as an estimated average glucose (eAG). The A1C test is translated to mg/dL, the number you see on a glucose finger prick or blood glucose meter.

Here are some examples of A1C converted to eAG:

• 7% A1C = 154 mg/dL eAG
• 8% A1C = 183 mg/dL eAG
• 9% A1C = 212 mg/dL eAG
• 10% A1C = 240 mg/dL eAG

EAG is useful because it is expressed in the same units as your glucose monitor, which is representative of a blood sugar reading at any given moment.

EAG will allow you to easily compare the average blood sugar levels over the past few months to where your glucose levels are at a given time in a home reading to see how your diet and lifestyle impact that day. 

What Medications and Other Factors Affect My A1C Results?

Other factors can affect your A1C results. If you were ill for a more extended time, had higher stress levels, and had poor sleep, these factors can also increase glucose levels. 

Anemia, kidney failure, liver disease, and pregnancy can falsely increase your A1C result. 

Certain medications like glucosteroids, opioids, and some HIV medications can increase your A1C level. Additionally, certain doses of vitamin E and C can alter the results. 

Chronic alcohol intake and high triglyceride levels can increase your A1C results. 

Share these conditions, medications, or concerns with your healthcare provider before scheduling or interpreting your A1C test. 

Your diet and lifestyle choices may not impact the results as much as you hoped when trying to counteract medications and other factors that elevate A1C results.

How Often Should I Get My AIC Checked?

A baseline A1C test is helpful, especially if you are over age 45 and have risk factors for prediabetes or type 2 diabetes, such as:

• Carrying extra weight.
• Past history of gestational diabetes.
• Have a parent, brother, or sister with type 2 diabetes.
• Physically active less than three times weekly.
• Are an African American, Hispanic or Latino, American Indian, Alaska Native, Pacific Islander, or Asian American person. 

Most healthcare providers test A1c every six months for people with diabetes.

However, they may increase the frequency depending on your health goals, recent illness, medications, or conditions that may have altered your A1C result. 

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Takeaway

A1C is an excellent marker for tracking glycemic control and giving patients and healthcare professionals a larger snapshot of how your body manages glucose levels.

You cannot lower your A1C overnight.

Daily choices–like diet and exercise resulting in healthy weight loss–can lower your glucose levels. You can see improvements in your A1C level in as little as six weeks.  

How a Dietitian Can Help

A registered dietitian can provide individualized lifestyle goals and meal plans to help you lower your A1C quickly and effectively. 

Nourish has dietitians who are Certified Diabetes Care and Education Specialists (CDCES) to help you meet your goals and improve your overall health. 

Book an appointment with a diabetes dietitian today.