What is a Normal Blood Sugar Range? A Complete Chart and Guide

18 Sep 2025 By Lori R. Roust, M.D.

What is a Normal Blood Sugar Range? A Complete Chart and Guide

Maintaining healthy blood sugar levels is vital for overall well-being, particularly for individuals with diabetes or those at risk. Blood sugar, or glucose, is the primary source of energy for the body, derived from the food we eat. Understanding what constitutes a normal blood sugar range, and the factors that can influence it, is essential for proactive health management.

This article provides a complete chart and guide to understanding normal blood sugar ranges, helping you navigate the complexities of glucose monitoring and management. We’ll explore different scenarios—fasting, postprandial (after eating), and bedtime—and offer actionable advice on maintaining healthy glucose levels.

Understanding Blood Sugar Levels: The Basics

Blood sugar levels are measured in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L). These measurements indicate the concentration of glucose in your blood at a specific point in time. Several factors influence these levels, including diet, physical activity, medication, stress, and underlying health conditions.

Why Monitoring Blood Sugar Matters

Regularly monitoring blood sugar levels is crucial for:

Diagnosing Diabetes: Identifying high blood sugar levels can lead to an early diabetes diagnosis.
Managing Diabetes: Tracking glucose levels helps individuals with diabetes adjust their diet, exercise, and medication.
Preventing Complications: Keeping blood sugar within the target range reduces the risk of long-term diabetes complications.
Overall Health: Understanding how your body responds to different foods and activities can optimize your overall health and energy levels.

Key Terms

Before diving into the charts and ranges, let’s define a few key terms:

Fasting Blood Sugar (FBS): The blood sugar level after an overnight fast (usually at least 8 hours).
Postprandial Blood Sugar (PPBS): The blood sugar level measured 1-2 hours after eating a meal.
HbA1c: Glycated hemoglobin; an average of blood sugar levels over the past 2-3 months.
Hyperglycemia: High blood sugar levels.
Hypoglycemia: Low blood sugar levels.

Normal Blood Sugar Ranges: A Detailed Chart

The following chart provides a detailed overview of normal, prediabetic, and diabetic blood sugar ranges for different situations. Note that these ranges can vary slightly based on individual health factors and specific guidelines from healthcare providers. Always consult your doctor for personalized advice.

Example:

If your fasting blood sugar consistently falls between 100-125 mg/dL, you may be diagnosed with prediabetes.
A postprandial blood sugar reading of 210 mg/dL indicates diabetes.
An HbA1c level of 7.0% indicates poor long-term blood sugar control in someone with diabetes.

Factors Influencing Blood Sugar Levels

Several factors can cause fluctuations in blood sugar levels. Understanding these factors can help you manage your glucose more effectively. A Simple Guide To Reading Your A1C Test Results Hba1C

1. Diet and Carbohydrates

Diet plays a significant role in blood sugar control. Foods high in carbohydrates are broken down into glucose, which raises blood sugar levels.

Simple Carbohydrates: Found in sugary drinks, processed foods, and refined grains, these are quickly absorbed, causing rapid spikes in blood sugar.
Complex Carbohydrates: Found in whole grains, legumes, and non-starchy vegetables, these are digested more slowly, resulting in a more gradual rise in blood sugar.

Example:

Drinking a can of soda (high in simple sugars) can cause a rapid spike in blood sugar levels.
Eating a bowl of oatmeal (complex carbohydrates) provides a more sustained release of glucose, preventing significant spikes.

Table: Glycemic Index (GI) of Common Foods

| Food | Glycemic Index (GI) | Effect on Blood Sugar | | :----------------------- | :-----------------: | :--------------------: | | White Bread | 75 | High | | Brown Rice | 68 | Medium | | Apple | 36 | Low | | Sweet Potato | 54 | Medium | | Chickpeas | 28 | Low |

Choosing foods with a low glycemic index (GI) can help maintain more stable blood sugar levels.

2. Physical Activity

Exercise helps lower blood sugar levels by increasing insulin sensitivity and using glucose for energy. Both aerobic exercise (like walking, running, or swimming) and resistance training (like weight lifting) are beneficial.

Example:

A brisk 30-minute walk can help lower blood sugar levels after a meal.
Regular resistance training can improve insulin sensitivity, making your body more efficient at using glucose.

3. Medication

For individuals with diabetes, medication is often essential for managing blood sugar levels. Types of medications include:

Insulin: Helps glucose enter cells for energy.
Oral Medications: Such as metformin, sulfonylureas, and DPP-4 inhibitors, which work through different mechanisms to lower blood sugar.

Example:

Someone with type 1 diabetes must take insulin multiple times a day to maintain normal blood sugar levels.
Someone with type 2 diabetes may take metformin to improve insulin sensitivity and reduce glucose production.

4. Stress

Stress hormones like cortisol and adrenaline can raise blood sugar levels by stimulating the release of glucose from the liver. Chronic stress can lead to consistently elevated blood sugar. Why Is My Fasting Blood Sugar Still High 8 Possible Reasons

Example:

Experiencing a stressful event can cause a temporary increase in blood sugar levels, even in individuals without diabetes.
Managing stress through relaxation techniques like yoga, meditation, or deep breathing can help stabilize blood sugar.

5. Illness

Illness can also impact blood sugar levels. During an infection or illness, the body releases hormones to fight the infection, which can increase blood sugar.

Example:

Having a cold or the flu can lead to higher blood sugar levels, requiring adjustments to medication or diet.
It's important to monitor blood sugar levels more frequently when sick and follow your healthcare provider's recommendations.

6. Sleep

Poor sleep quality or insufficient sleep can affect blood sugar levels. Lack of sleep can increase insulin resistance and lead to higher glucose levels.

Example:

Regularly getting less than 7 hours of sleep can increase the risk of developing insulin resistance and type 2 diabetes.
Prioritizing good sleep hygiene (consistent sleep schedule, dark and quiet room, avoiding caffeine before bed) can improve blood sugar control.

How to Monitor Your Blood Sugar Levels

Monitoring your blood sugar levels involves using a blood glucose meter (glucometer) or a continuous glucose monitor (CGM).

1. Blood Glucose Meter (Glucometer)

A glucometer requires a small blood sample, usually taken from a fingertip, to measure blood sugar levels. Here’s how to use one:

Wash Your Hands: Use soap and water to clean your hands thoroughly.
Prepare the Lancing Device: Insert a lancet into the lancing device.
Obtain a Blood Sample: Use the lancing device to prick your fingertip and gently squeeze to get a small drop of blood.
Apply Blood to Test Strip: Insert the test strip into the glucometer and apply the blood sample to the designated area on the strip.
Read the Results: The glucometer will display your blood sugar level.

2. Continuous Glucose Monitor (CGM)

A CGM is a device that continuously tracks blood sugar levels throughout the day and night. It involves inserting a small sensor under the skin, which measures glucose levels in the interstitial fluid.

Benefits of CGM:

Provides real-time glucose readings.
Shows trends and patterns in blood sugar levels.
Alerts users to high and low glucose levels.
Reduces the need for frequent fingersticks.

Example:

CGMs can help athletes optimize their nutrition and exercise strategies by providing continuous feedback on how different activities impact blood sugar levels.
Individuals with unstable blood sugar can use CGMs to get alerts when their glucose levels are too high or too low, allowing them to take immediate action.

Strategies for Maintaining Healthy Blood Sugar Levels

Maintaining healthy blood sugar levels involves adopting lifestyle habits that support stable glucose.

1. Balanced Diet

Focus on Whole Foods: Prioritize fruits, vegetables, whole grains, and lean proteins.
Control Carbohydrate Intake: Be mindful of the amount and type of carbohydrates you consume.
Choose Low-Glycemic Foods: Opt for foods with a low glycemic index to avoid rapid spikes in blood sugar.
Stay Hydrated: Drink plenty of water to help regulate blood sugar levels.

2. Regular Exercise

Aim for Regular Activity: Get at least 150 minutes of moderate-intensity aerobic exercise per week.
Include Resistance Training: Incorporate weight lifting or other forms of resistance training to improve insulin sensitivity.
Time Your Workouts: Pay attention to how exercise affects your blood sugar levels and adjust your timing accordingly.

3. Stress Management

Practice Relaxation Techniques: Use yoga, meditation, deep breathing, or other relaxation techniques to reduce stress levels.
Get Enough Sleep: Aim for 7-9 hours of quality sleep each night.
Set Boundaries: Learn to say no to commitments that add unnecessary stress to your life.

4. Regular Monitoring

Track Your Levels: Regularly monitor your blood sugar levels to understand how different factors impact your glucose.
Keep a Log: Record your food intake, exercise, stress levels, and blood sugar readings to identify patterns and trends.
Share Information with Your Healthcare Provider: Discuss your findings with your doctor to adjust your management plan as needed.

5. Medication Adherence

Follow Your Doctor's Instructions: Take your medications as prescribed and don't skip doses.
Monitor for Side Effects: Be aware of potential side effects of your medications and report any concerns to your doctor.
Work with Your Healthcare Team: Regularly review your medication regimen with your doctor or pharmacist to ensure it remains effective and safe.

What to Do If Your Blood Sugar Is Too High (Hyperglycemia)

Hyperglycemia occurs when blood sugar levels are higher than the target range. If you experience hyperglycemia, take the following steps:

Check Your Blood Sugar: Confirm the high reading with a blood glucose meter.
Drink Water: Stay hydrated to help flush out excess glucose.
Exercise: If appropriate, engage in light to moderate exercise to lower blood sugar levels.
Adjust Medication: If you take insulin or other diabetes medications, follow your doctor's instructions for adjusting the dose.
Contact Your Healthcare Provider: If your blood sugar remains high despite these measures, seek medical advice.

Symptoms of Hyperglycemia:

Frequent urination
Increased thirst
Blurred vision
Fatigue
Headache

What to Do If Your Blood Sugar Is Too Low (Hypoglycemia)

Hypoglycemia occurs when blood sugar levels are lower than the target range. If you experience hypoglycemia, take the following steps:

Check Your Blood Sugar: Confirm the low reading with a blood glucose meter.
Consume Fast-Acting Carbohydrates: Eat or drink something containing 15-20 grams of fast-acting carbohydrates, such as glucose tablets, fruit juice, or regular soda.
Wait 15 Minutes: Recheck your blood sugar after 15 minutes.
Repeat if Necessary: If your blood sugar is still low, repeat the process.
Eat a Snack or Meal: Once your blood sugar is back in the target range, eat a snack or meal containing carbohydrates and protein to stabilize your levels.
Contact Your Healthcare Provider: If you experience frequent episodes of hypoglycemia, seek medical advice.

Symptoms of Hypoglycemia:

Shakiness
Sweating
Dizziness
Hunger
Confusion
Irritability
Rapid heartbeat

Conclusion

Understanding and maintaining a normal blood sugar range is critical for overall health, especially for those with diabetes or at risk. By monitoring your blood sugar levels, adopting a healthy lifestyle, and working closely with your healthcare provider, you can effectively manage your glucose levels and prevent complications. Use the chart and guide provided in this article to inform your decisions, but always consult with medical professionals for tailored advice. Your health is your greatest asset; invest the time and effort to manage it wisely.