Does Aging Change Blood Glucose Levels?

Many people worry about developing insulin resistance, prediabetes, or diabetes as they age. But does aging cause changes in blood glucose levels, ultimately leading to the onset of type 2 diabetes? Not necessarily, but the relationship between aging and insulin sensitivity is complex.

Blood glucose management can be a telling indicator of overall health, but there are no standardized normal blood sugar levels by age group. In reality, your ideal blood sugar range should account for lifestyle factors, chronic health conditions, and long-term health goals. Still, recognizing healthy blood sugar ranges can help you understand how your body is utilizing glucose to avoid chronically high blood sugar levels and resulting medical conditions.

This article is not meant to replace a personalized treatment plan from your trusted healthcare professional. But together, we’ll break down the science behind blood glucose control and age, and we’ll review ways to manage your labs as you get older.

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Testing Blood Sugar Levels

Your healthcare provider may recommend that you undergo one or more tests to either rule out or diagnose prediabetes or diabetes. But before you start exploring laboratory tests, it’s essential to know what they’re testing for.

According to the American Diabetes Association (ADA) and the Centers for Disease Control and Prevention (CDC), the different types of diabetes include:^{1, 2}

• Prediabetes: Prediabetes is characterized by blood sugar levels that are higher than the normal range but not high enough to be diagnosed with type 1, type 2, or gestational diabetes.
• Type 1 Diabetes: This is an autoimmune condition in which the immune system attacks the insulin-producing cells, inadvertently turning off insulin production. Unfortunately, type 1 diabetes cannot be prevented.
• Type 2 Diabetes: Type 2 diabetes is a chronic condition in which the body doesn't make enough insulin or doesn’t use it correctly, resulting in elevated blood sugar levels. This type of diabetes can be prevented through lifestyle habits, including dietary intake and regular physical activity.
• Gestational Diabetes: This type of diabetes is characterized by high blood sugar levels during pregnancy. It usually resolves after delivery.

You may notice symptoms of high blood sugar, such as frequent urination, or symptoms of low blood sugar, such as dizziness. However, it’s challenging to know without actual measurements. 

To assess your risk for diabetes, your doctor may recommend various blood glucose tests, such as:

• Hemoglobin A1C Test: The hemoglobin A1c or HbA1c test takes a small sample of blood and determines your average blood sugar levels over the past 3 months.³‍
• Fasting Plasma Glucose Test: A fasting plasma glucose test is typically completed in the morning as it requires you to fast for at least 8 hours before your blood is drawn. It requires a glucometer and test strips to analyze your blood glucose levels after you’ve had nothing to eat or drink except for water.‍
• Oral Glucose Tolerance Test: The oral glucose tolerance test is typically used to test for gestational diabetes during pregnancy. If your doctor prescribes an oral glucose tolerance test, you will eat a normal carbohydrate diet for three days leading up to the test and fast for 10-16 hours before your scheduled test. At your appointment, your provider will take a blood sample to establish a baseline blood sugar level. Then, you'll drink a liquid glucose product and test again in timed increments to see how your body responds to the glucose.

Why Do Blood Sugar Levels Increase With Age?

Some people lose the ability to regulate their blood glucose as well as they did when they were younger. Increased body fat and decreased physical fitness are major contributors to a decline in glucose tolerance between young adulthood and middle age.⁴ 

Insulin resistance occurs when your pancreas needs to produce more insulin to regulate your blood sugar because your body’s cells have become resistant to its effects. The insulin-producing beta cells in your pancreas will produce as much insulin as possible for as long as possible until they burn out.

Insulin insensitivity may change with age due to:

• Increased Belly Fat: Body fat tends to redistribute as we age, often resulting in an increase in abdominal fat.⁵ Research has found that visceral fat, the belly fat found deep in the abdominal cavity, is an independent marker in predicting insulin resistance.⁶‍
• Decreased Muscle Mass: Sarcopenia, or the loss of muscle mass in older adults, has been linked to various adverse health outcomes. It’s estimated that sarcopenia affects 10-16% of older adults worldwide, but its prevalence is higher in those with diabetes. Research has found that it affects approximately 18% of those living with diabetes, indicating muscle mass plays a role in glycemic control.⁷‍
• Changes in Mitochondrial Efficiency: Mitochondria are cell organelles that produce the energy needed to power the body’s biological reactions, including those that affect insulin sensitivity. Mitochondrial dysfunction is a hallmark of the aging process, further connecting age with changes in blood sugar levels.^{8, 9}‍
• Hormonal Changes: Aging has been linked to changes in hormonal patterns, like those that occur during menopause.¹⁰ The decrease in hormone activity can be detrimental to many bodily functions, including those that influence blood sugar levels.‍
• Increased Oxidative Stress: Aging contributes to the production of oxygen-reactive species, causing oxidative stress.¹¹ Unfortunately, oxidative stress and hyperglycemia or high blood sugar levels go hand in hand, each increasing the other condition.¹² Inflammation is also a marker of oxidative stress. Read more about how to reduce inflammation.¹³‍
• Limited Physical Activity: Many adults tend to engage in less physical activity as they age. Research has shown that low physical activity levels are strongly associated with abnormal blood glucose levels.¹⁴

Normal Blood Sugar Levels for Adults With and Without Diabetes

Normal blood sugar levels for those without diabetes differ slightly from those with diabetes, regardless of age group. However, older adults may be at an increased risk of hyperglycemia and hypoglycemia or low blood sugar if they’re not mindful of their nutritional intake.

Low blood sugar levels can increase the risk of:¹⁵ 

• Falling
• Confusion
• Cardiovascular events such as heart attacks and chest pain
• Cognitive function declines
• Fatigue
• Dizziness

Older adults, especially those with a complex medical history, need to maintain a specific target glucose range to reduce the risk of hypoglycemia. Enter blood sugar tests.

Target Blood Sugar Ranges for Adults 

This normal blood sugar levels chart provides generalized guidance for the average adult:^{15, 16} 

Adults Without Diabetes

• Fasting Blood Sugar: 70—99 mg/dL
• Before Eating: 80—130 mg/dL
• 1-2 Hours After Eating (Post-prandial): 80—140 mg/dL
• Bedtime Target: 100—140 mg/dL
• Target hgA1C: Below 5.7%

Healthy Adults With Diabetes

• Fasting Blood Sugar: Less than 100 mg/dL
• Before Eating: 80—130 mg/dL
• 1-2 Hours Post-prandial: 80—180 mg/dL
• Bedtime Target: 100—140 mg/dL
• Target hgA1C: 7% or less

Older, Healthy Adults With Diabetes

• Fasting Blood Sugar: 90—130 mg/dL
• Bedtime Target: 90—150 mg/dL
• Target hgA1C: 7.5% or less

Adults With Complex Health Problems

• Fasting Blood Sugar: 90—150 mg/dL
• Bedtime Target: 100-180 mg/dL
• Target hgA1C: 7.5% or less

Adults With Very Poor Health and Complex Medical Problems

• Fasting Blood Sugar: 100—180 mg/dL
• Bedtime Target: 110—200 mg/dL
• Target hgA1C: 8.5% or less

Of course, it’s important to remember that your healthcare provider will provide you with individualized guidance regarding your recommended blood sugar target range. Your doctor will account for your type of diabetes (prediabetes, type 1 diabetes, or type 2 diabetes), nutritional intake, and physical activity. They may require an A1C test to start your diabetes management and then recommend regular fast blood sugar level tests.

<p class="pro-tip"><strong>Also Read: </strong><a href=average-glucose-ranges>What Are Normal Blood Sugar Levels for Non-Diabetic People?</a>.</p>

How Aging Affects Blood Sugar Levels

Insulin and glucagon are pancreatic hormones that regulate blood glucose levels. After eating, carbohydrates are broken down and absorbed into the bloodstream, increasing blood sugar levels. A healthy pancreas should then produce more insulin to help glucose enter our cells and be used for energy. Unfortunately, this process becomes less efficient with age. 

How Age-Related Muscle Changes Lead to Insulin Resistance

Skeletal muscle can absorb up to 85% of circulating blood glucose in a healthy person. But muscle mass decreases with age, so this process also becomes less efficient, allowing glucose to stay in the bloodstream for longer periods.¹ 

A decrease in muscle mass is a major factor that contributes to insulin resistance with aging.

However, there are other age-related changes in muscles that also contribute to insulin resistance, including:

• An Increase in Mitochondrial Dysfunction: Makes it more difficult to convert macronutrients to energy.
• A Decrease in Mitochondrial Number: There is a positive correlation between the number of skeletal muscle mitochondria and insulin sensitivity.
• Increased Inflammation: Increases insulin resistance. 
• An Increase in Fat Deposits: As lipids or fats increase in muscle cells, they affect enzymes involved in the insulin signaling pathway and increase inflammation.
• Exposure to More Oxidative Stress: Makes metabolism less efficient and increases insulin resistance.
• Decreased Ability to Get Rid of Non-functional or Poorly Functioning Muscle Cells.

The Importance of Blood Glucose Awareness and Control

With age, prediabetes and diabetes are more prevalent, and older adults are at increased risk for complications from diabetes.¹⁵ 

However, researchers at the Johns Hopkins Bloomberg School of Public Health found that older adults (over age 70) with prediabetes don’t usually develop type 2 diabetes. In their study, 12% of older adults with elevated blood glucose progressed to diabetes, but a higher percentage regressed to normal blood glucose. Prediabetes is still considered a predictor of type 2 diabetes for young and middle-aged adults.¹⁷

Nearly 38% of the U.S. adult population has prediabetes.¹⁸ While prediabetes is a common condition, that does not mean it should not be taken seriously. Prediabetes is associated with an increased risk of:¹⁹

• Cardiovascular disease
• Coronary heart disease
• Stroke
• All-cause mortality

Type 2 diabetes also increases the risk of:

• Chronic kidney disease
• Small vessel disease  
• Immune dysfunction
• Diabetic ketoacidosis

Increased blood glucose damages the inner lining of blood vessels. Your heart must pump harder to overcome the increased resistance that narrowed and scarred blood vessels impose. Blood vessel damage secondary to high blood glucose levels affects people of all ages, but the risk of cardiovascular disease from high blood glucose is much higher in older adults.³

As insulin resistance progresses, it can lead to metabolic syndrome, a list of risk factors that can contribute to cardiovascular disease and type 2 diabetes.²⁰ Of these, the most common consequence of uncontrolled blood sugar and insulin resistance is type 2 diabetes. However, if you’re at increased risk for type 2 diabetes, it’s possible to make lifestyle changes to decrease that risk. Read more about the many benefits of having stable blood sugar. 

Does Gender Make a Difference?

A recent study with 12.8 million participants monitored the amount of glucose in their systems after fasting and discovered that:²¹

• Men had a 3.0mg/dL higher fasting blood sugar levels than women had until age 73 years.
• After age 73, women had higher fasting glucose levels than men.
• Fasting glucose increased with age until age 62 to 63 years.
• Women had an increase in fasting glucose starting at age 28 and continuing to 86 to 99 years.
• The peak difference between the sexes was at 48-51 years, where men had a 6.1 mg/dL higher fasting glucose level than women.
• Lower blood sugar levels between 80 and 94 mg/dL were associated with the lowest mortality, regardless of age and sex.

6 Ways to Manage and Reduce Your Blood Sugar Levels as You Age

There are many steps you can take to manage your blood glucose and improve your overall health. Every lifestyle change you make to reduce your risk of type 2 diabetes also reduces your risk of cardiovascular disease, cancer, kidney disease, obesity, and many other diseases associated with uncontrolled blood glucose.

While they cannot replace medical advice from your healthcare provider, consider these tips to manage your blood sugar levels:

Manage Your Weight

Many factors contribute to increased weight gain with aging, including a gradual loss of muscle mass, decreased physical activity, declines in estrogen and testosterone, and a decrease in fat-burning response to catecholamines.¹ Losing even 5% to 10% of excess weight can greatly affect your overall health. 

Exercise

Any type of physical activity can help improve your glucose sensitivity and help with weight management. The Centers for Disease Control and Prevention and the American Heart Association recommend adults engage in 150 minutes per week of moderate aerobic exercise, 75 minutes of vigorous exercise, or a combination of both, and resistance exercise to strengthen all major muscle groups two days per week.²²  

Exercise increases glucose uptake into skeletal muscle by 50-fold.²⁶ In one study, exercise was more effective than metformin (a diabetes drug) in controlling blood sugar and reducing the risk of cardiovascular disease in adults with type 2 diabetes.²² 

Monitor Your Sugar Intake

Minimize consumption of simple and processed sugars. According to a U.S. Department of Agriculture report, the average American consumes 156 pounds of sugar yearly. Reduce sugar consumption by choosing whole foods whenever possible and watching for added sugar in processed foods. Rely on blood glucose tests to assess your body’s reaction to meals and snacks, and keep glucose tablets on hand in case your sugar drops too low.

Get Adequate Vitamin D

Vitamin D helps regulate insulin secretion, increase insulin sensitivity, and reduce inflammation.²³ Just 20 minutes in the sunshine twice weekly can provide enough exposure to ultraviolet B radiation to meet your vitamin D requirements. 

According to the National Institutes of Health, adults need 600 international units (IU) of vitamin D daily until the age of 70, when needs increase to 800 IU daily.²⁴ Consider supplements or choose foods enriched in vitamin D to meet your daily requirements.

Get Plenty of Restful Sleep

Disrupted or inadequate sleep can increase your risk of metabolic syndrome, high blood pressure, abnormal blood lipids, type 2 diabetes, cardiovascular disease, and insulin resistance.²⁵ Try to prioritize a bedtime routine and aim for 7 to 8 hours of restful, uninterrupted sleep each night. 

For more tips, read Improving Sleep Quality: How to Not Wake Up Tired.

Choose a Healthy Diet

High-fiber, high-protein foods that are healthy sources of fats are everyday foods that stabilize blood sugar levels and support overall wellness. For more ideas on building a healthy diet full of nutritious foods that can stabilize your blood sugar, read the ultimate list of high-fiber, low-carb foods. 

Using CGMs and the Signos App to Manage Blood Sugar Levels

Metabolic changes typically begin 10 to 13 years before type 2 diabetes is diagnosed. Early detection of changes in glucose sensitivity provides more opportunities to make lifestyle changes that may delay or even prevent type 2 diabetes. Studies have shown that a single fasting blood glucose, hemoglobin A1C, or 2-hr OGTT may miss many people later diagnosed with type 2 diabetes.¹ 

Using a continuous glucose monitor and the Signos app, you can track your blood sugar and identify trends in your diabetes care. Knowing which lifestyle factors influence your blood glucose levels and how to mitigate your glucose spikes can help you reduce your risk of type 2 diabetes and its associated diseases. 

A CGM and the Signos app provide you with real-time data on how your body reacts to the foods you eat, as well as recommendations on how to make small tweaks to your diet that can have a big impact over time. 

Optimizing your metabolic health is a lifelong endeavor that should be prioritized by anyone who wants to maximize their number of disease-free years.

<p class="pro-tip"><strong>Learn More: </strong><a href=what-factors-affect-blood-sugar>What Factors Affect Blood Sugar Levels?</a>.</p>