Normal Blood Sugar Levels by Age: Glucose Charts & What They Mean for Your Health

Most of us have heard the term “blood sugar” or “glucose,” but unless we’ve been diagnosed with diabetes or prediabetes, we often don’t pay it much attention. But here’s the truth: blood sugar affects everyone. From the moment you wake up to the time you go to bed—and even while you sleep—your body is constantly working to regulate your glucose levels. It plays a huge role in how much energy you have, how well you sleep, how clear your thinking is, how much fat you store, and how likely you are to develop chronic diseases.

Whether you're a parent trying to understand your child's health, a teenager managing growing energy needs, an adult looking to lose weight, or a senior working to stay healthy and independent, your blood sugar levels matter.

In this guide, we’re going to break down exactly what normal blood sugar looks like by age, how it's measured, why it changes over time, and what you can do to keep it within a healthy range. We’ll also show you helpful charts to simplify what can sometimes feel like confusing numbers.

What Is Blood Glucose and How Is It Measured?

Blood glucose, often referred to simply as “blood sugar,” is the amount of sugar (glucose) in your blood at a given time. Glucose is your body’s main source of energy. It comes from the food you eat—especially carbohydrates—and travels through your bloodstream to your cells. Once there, it’s used for fuel or stored for later.

Your body works hard to keep your glucose in a healthy range, and this job mainly falls to a hormone called insulin. Insulin helps move glucose out of your blood and into your cells. If there’s too much glucose, your pancreas releases insulin to bring it down. If there’s too little, your body releases other hormones to bring it back up. It's a constant balancing act.

There are a few different ways to measure blood sugar:

Fasting blood glucose is measured after not eating for at least 8 hours. Postprandial blood glucose is measured 1 to 2 hours after eating. Random glucose is taken at any time, regardless of meals. A1C (or HbA1c) reflects your average blood sugar level over the past 2–3 months.

Each of these tests gives different information. Together, they paint a full picture of your blood sugar health.

Blood sugar is usually measured in milligrams per deciliter (mg/dL) in the U.S., or in millimoles per liter (mmol/L) in many other countries. It’s important to know which unit you’re looking at so you can interpret the results correctly.

RELATED READ: Blood Sugar Conversion Chart & Calculator: Easy mg/dL to mmol/L Guide (With Tools & Tips)

Why Blood Sugar Levels Change with Age

Your blood sugar levels are not static throughout life. They tend to shift depending on your age, hormonal changes, body composition, and activity level. In children, blood sugar is usually tightly regulated due to their high energy demands and fast metabolism. Teenagers may see fluctuations due to puberty and growth hormones. Adults often experience blood sugar changes based on stress, diet, and lifestyle. And older adults tend to become more insulin resistant over time, meaning their bodies don’t use insulin as efficiently.

This age-related change in insulin sensitivity is one reason why the risk of prediabetes and type 2 diabetes increases with age. Hormones play a role, too. As estrogen, testosterone, growth hormone, and other key regulators decline, they can affect how your body processes glucose.

That’s why knowing what’s normal for your age—and watching for early signs of trouble—is so important.

Normal Blood Glucose Levels by Age (Fasting and Post-Meal)

Let’s take a closer look at what normal blood sugar look like at different life stages. These numbers are general guidelines, not hard rules. Always speak to a healthcare professional to interpret your personal results.

Children (0–12 years)

Children’s bodies are typically very good at regulating glucose. They need steady fuel for growth and development, but their metabolism burns through glucose quickly.

For most healthy children, fasting blood sugar usually falls between 70 and 100 mg/dL. After eating, it can go up to about 140 mg/dL, but it typically returns to baseline within 1 to 2 hours.

If your child’s blood sugar is consistently high or low, it could point to an underlying issue, and it’s worth investigating with a pediatrician.

Teenagers (13–19 years)

Teenagers experience significant hormonal changes, especially during puberty, which can lead to temporary spikes in insulin resistance. This means the body might not respond to insulin as effectively, causing blood sugar to run higher than normal—even with the same food or activity level.

Despite this, normal fasting blood sugar for teens is still around 70–100 mg/dL, and post-meal levels shouldn’t exceed 140 mg/dL too often. If levels consistently rise above this range, it may be a sign of early insulin resistance or prediabetes.

Lifestyle habits, such as poor diet, lack of sleep, stress, and too much screen time, can all make glucose harder to manage during these years.

Adults (20–59 years)

By adulthood, blood sugar regulation is largely determined by your lifestyle—what you eat, how much you move, how you sleep, how stressed you are, and your genetic predisposition.

For healthy adults, fasting blood sugar should be between 70 and 99 mg/dL. After meals, it’s normal for glucose to rise, but it should come back down below 140 mg/dL within two hours. An A1C level below 5.7% is considered normal.

If fasting glucose consistently reads between 100 and 125 mg/dL, it’s labeled as prediabetes. If it’s 126 mg/dL or higher on more than one occasion, that could indicate type 2 diabetes.

Even if you’re not diabetic, keeping glucose in a tight range is linked with better energy, mood, weight control, and long-term health.

Older Adults (60+ years)

As we age, insulin sensitivity tends to decline, and blood sugar levels may rise slightly. Muscle mass decreases, metabolism slows, and hormones that help regulate glucose—like DHEA, testosterone, and growth hormone—begin to drop.

Despite these changes, healthy older adults should still aim for fasting blood sugar below 100 mg/dL. However, some doctors may allow slightly higher levels (up to 110 or even 120 mg/dL fasting) if there are no signs of diabetes and the person is otherwise healthy.

After meals, it’s ideal for glucose to stay under 140 mg/dL, but again, slightly higher levels may be tolerated, especially if there's a risk of hypoglycemia (low blood sugar). The goal is to find a safe balance that protects brain, heart, and metabolic health while avoiding drops in energy or confusion.

Note: For older adults, especially those with other health conditions or at risk of low blood sugar, some guidelines accept slightly higher fasting and post-meal levels to avoid complications.

Units Explained:

• These values are in mg/dL (milligrams per deciliter), the standard unit used in the U.S.
• In countries using mmol/L, you can divide the mg/dL number by 18. For example, 100 mg/dL = 5.6 mmol/L.

Normal Glucose Levels: Fasting vs Post-Meal vs A1C

Many people get confused about which glucose numbers matter most. Is fasting more important? What about A1C? Here’s a breakdown:

Fasting blood sugar shows how your body handles glucose when you haven’t eaten for 8+ hours. This can reflect how well your insulin is working at rest.

Postprandial (post-meal) glucose tells you how your body responds to food. It gives clues about how quickly your pancreas can release insulin and how sensitive your cells are to it.

A1C (hemoglobin A1C) provides a big-picture view. It reflects your average blood sugar over the past 2–3 months. This helps detect trends even if your daily glucose fluctuates.

For non-diabetics, the goal is generally:

• Fasting glucose: under 100 mg/dL
• 1–2 hours post-meal: under 140 mg/dL
• A1C: under 5.7%

These ranges give a target for good health, not just diabetes prevention.

RELATED READ: Normal Glucose Levels: What’s Good, What’s Not, and How to Keep Yours in Check

What Do Abnormal Glucose Levels Mean?

If your blood sugar is often outside the normal range, it could point to a deeper issue.

When glucose levels are too high, it’s called hyperglycemia. This can be caused by insulin resistance, where the body no longer responds properly to insulin. If left unchecked, hyperglycemia can damage your blood vessels, nerves, kidneys, eyes, and brain. It’s also a sign of prediabetes or diabetes.

Symptoms of high blood sugar may include increased thirst, frequent urination, fatigue, blurry vision, and slow healing. But many people have no symptoms at all—especially in the early stages.

When glucose levels are too low, it’s called hypoglycemia. This can happen from skipping meals, intense exercise without fuel, or using certain medications. Symptoms include shakiness, sweating, irritability, dizziness, and even confusion or fainting. Severe hypoglycemia can be dangerous if not addressed quickly.

That’s why it’s essential to stay in the sweet spot—not too high, not too low.

When to Check Your Blood Sugar (Even If You’re Not Diabetic)

You don’t have to be diabetic to benefit from monitoring your glucose. In fact, many people are discovering the benefits of tracking their blood sugar to improve focus, energy, mood, weight loss, and long-term health.

If you’re dealing with fatigue, belly fat, cravings, or brain fog, unstable blood sugar could be the culprit. Monitoring glucose gives you real-time insight into what your body needs.

You can test at home using a finger-prick glucose meter or a Continuous Glucose Monitor (CGM), which sticks to your arm and tracks your levels all day.

Best times to check:

• First thing in the morning (fasting)
• 1–2 hours after meals
• Before and after exercise
• During symptoms like fatigue, headache, or shakiness

Over time, you’ll start to see patterns—and understand which foods and habits help or hurt your glucose balance.

How to Optimize and Maintain Healthy Blood Sugar Levels

The good news? You have a lot of control over your glucose health. Here are the most important strategies to help you stay in range:

Start with food. Prioritize meals with protein, healthy fats, and fiber to blunt glucose spikes. Avoid ultra-processed carbs, sugary drinks, and snacks that are mostly empty starch.

Stay active. Even a 10-minute walk after meals can dramatically lower blood sugar. Strength training improves insulin sensitivity over time.

Sleep matters more than you think. Poor sleep increases stress hormones and makes your body more insulin resistant the next day.

Manage stress. Chronic stress triggers cortisol, which pushes glucose higher. Mindful practices, breathwork, or even just breaks during the day help regulate this.

Avoid skipping meals. Eating regularly—especially if you're prone to low blood sugar—keeps glucose levels steady.

Some people also benefit from supplements like berberine, magnesium, or alpha-lipoic acid. But talk to your doctor before adding anything new.

Frequently Asked Questions (FAQs)

1. What is a normal glucose level for a 70-year-old?

For most healthy seniors, a fasting blood sugar between 70–110 mg/dL is acceptable. Slightly higher ranges may be tolerated if there’s no risk of diabetes complications or low blood sugar.

2. What should your blood sugar be 2 hours after eating?

For most people, it should be under 140 mg/dL. If it frequently spikes above this, it may be time to assess your diet or insulin sensitivity.

3. Can stress or dehydration raise blood sugar?

Yes. Stress triggers hormones like cortisol and adrenaline, which raise blood glucose. Dehydration can concentrate your blood, making glucose levels appear higher than normal.

4. What is the danger level for blood sugar?

A fasting glucose over 126 mg/dL or a random reading over 200 mg/dL may indicate diabetes and should be evaluated immediately. On the low end, anything under 70 mg/dL is considered hypoglycemic and can be dangerous if not addressed.

5. How often should non-diabetics check blood sugar?

You don’t need to test every day, but doing occasional checks—especially after meals or during fatigue—can provide helpful insights into your health trends.

Conclusion: Know Your Numbers, Take Control

Blood sugar is one of the most powerful markers of your health—and the good news is, it’s also one of the most changeable. Whether you’re trying to lose weight, boost energy, sharpen your mind, or prevent chronic disease, stable glucose levels are your ally.

By understanding what’s normal for your age, tracking your numbers, and making simple lifestyle shifts, you can take charge of your health at any stage of life.

If you haven’t looked at your blood sugar lately, now’s the perfect time to start. Your future self will thank you.