Medical terminology can be confusing, even when the item in question is something fundamental, like blood sugar. You’ve probably heard someone in your life talk about their blood sugar before. In truth, blood sugar levels affect everyone, not just those with diabetes. Temporary rises and falls in blood sugar can cause a host of problems, such as fatigue, weakness, nausea, vomiting, dizziness, and headaches. Ongoing issues with blood sugar can lead to serious health conditions.
Learning about normal blood sugar levels is helpful for everyone and critical for those managing endocrine conditions like diabetes or hypoglycemia. If you’re not sure what “normal” should look like, check out this guide to normal blood sugar levels and diabetes test range numbers.
What Is Blood Sugar?
Blood sugar level refers to the amount of sugar or glucose in your bloodstream. Glucose comes from the foods you eat that are rich in carbohydrates, such as bread, potatoes, pasta, rice, and fruit. They turn into glucose in your body and can cause your blood sugar level to rise. A higher-than-normal blood glucose level is hyperglycemia. In contrast, a lower-than-normal blood glucose level is hypoglycemia. Both can have negative effects on our health, so it is important to maintain a normal blood sugar level.
What Is a Normal Blood Sugar Level?
Your doctor may order a series of blood tests if you experience symptoms that indicate that you have high blood sugar, like fatigue, nausea, blurred vision, feeling thirsty, and needing to use the bathroom frequently.
Blood sugar tests measure the amount of glucose in a small sample of the patient’s blood. This tests if you have diabetes or monitors your blood sugar level if you are already have diabetes. Normal blood sugar levels vary throughout the day for everyone. They are affected by the foods we eat, the beverages we drink, and the exercise (or lack of exercise) we get. A “normal” result or range will depend on:
- The type of test
- If the measure is against standard clinical cut-off points for diagnosis of diabetes
- If the measure is against your doctor’s recommendations as a healthy target range for you with diabetes.
Blood Sugar Level Tests
There are four different types of common tests, each with varying ranges for what is normal for the majority of healthy individuals:
- Random blood glucose test – you take a blood sample at any time of the day, without a period of fasting. A normal range for this test is 125 mg/dL to 140 mg/dL (milligrams per decilitre of blood). A blood sugar level of 200 mg/dL or higher suggests diabetes, regardless of when you last ate.
- Fasting blood glucose test – you take a blood sample after you have not eaten anything for at least 8 hours. A normal fasting blood sugar level is between 70 and 100 mg/dL. A range from 100 to 125 mg/dL is prediabetic, and a level of 126 mg/dL or higher is associated with diabetes.
- Oral glucose tolerance test (OGTT) – following a fasting blood glucose test, you will then drink a sugary liquid, and you will get more blood sugar levels tests periodically for the next 2 hours. After 2 hours, a blood sugar level of less than 140 mg/dL is normal. A reading between 140 and 199 mg/dL indicates prediabetes. And a reading of more than 200 mg/dL after two hours indicates diabetes.
- A1C test (also known as a HbA1c test or Glycated hemoglobin test) – this is a lab test that measures the percentage of blood sugar attached to hemoglobin. Hemoglobin is the oxygen-carrying protein in red blood cells. This test shows the average level of blood sugar (glucose) over the previous 2-3 months. A normal result is below 5.7%. Levels between 5.7 and 6.4 percent are prediabetic, and levels of 6.5 or higher are associated with diabetes.
If you have Type 1 or Type 2 diabetes and monitoring your blood glucose levels, your targets may vary but generally speaking, it would be:
- between 70 to 125 mg/dL before meals (fasting blood glucose level), and under 165 mg/dL after meals
- A1C test results should be below 6.5%
Normal Blood Sugar Level Immediately After Eating
Eating a meal affects your blood sugar. When a person with normal blood sugar responses eats a meal, the blood sugar will spike but should not exceed 140 mg/dL. The exact amount of the spike will vary based on the foods that you eat. Approximately two hours after eating a meal, normal blood sugar should fall below the 140 mg/dL maximum if you do not have blood sugar issues. If you have diabetes or other endocrine conditions, you will have different blood sugar levels that require close monitoring.
What Is Diabetes?
Diabetes is a disorder that affects the body’s metabolism and how it processes food for energy, resulting in higher blood sugar levels than normal (hyperglycemia). This occurs when there is a problem with the insulin response in the body. Insulin is a hormone created by the pancreas specifically to manage the level of glucose in the blood to ensure that sugar is transferred to the body’s cells for energy.
Type 1 Diabetes
Type 1 diabetes occurs when the pancreas stops making insulin or makes very little. The reasons for this still aren’t completely understood, although genetics may play a role in many cases. It’s possible to develop Type 1 diabetes at any age, but it often first appears in children or at a young age. If you develop type 1 diabetes, you will have to take insulin daily to ensure sugar doesn’t build up in your blood to a dangerous level. The type and frequency of insulin doses vary from person to person.
Type 2 Diabetes
Type 2 diabetes most often develops in middle-aged adults. The reasons the body develops a resistance to insulin in some people aren’t fully known. However, scientists have linked diet and obesity to an increased risk of Type 2 diabetes.
Gestational Diabetes
Gestational diabetes is a form of insulin resistance due to hormone changes in pregnancy. This type of diabetes usually disappears after giving birth. However, it has been linked to a greater risk of Type 2 diabetes in the future.
Normal Blood Sugar Level in a Child
Type 1 diabetes is most commonly diagnosed in children. The inability to produce insulin is often detected earlier in life, while Type 2 diabetes is often developed later in life due to a combination of genetic and lifestyle factors. For children with Type 1 Diabetes, the target blood sugar level before meals is between 70 and 125 mg/dL and between 90 and 165 mg/dL after eating. For non-diabetic children, a normal blood sugar level is 60 to 110 mg/dL (before eating) and 160 to 200 mg/dL (after eating).
Normal Blood Sugar Level in Pregnancy
Gestational diabetes is a type of diabetes that happens for the first time when a woman is pregnant. Most of the time, your blood sugar levels will return to normal after the baby is born. However, you will closely monitor it during pregnancy. Having gestational diabetes can increase your child’s risk of developing type 2 diabetes. Women with a history of gestational diabetes have a nearly 10-fold higher risk of developing Type 2 diabetes than those with normal glycaemic levels during pregnancy.
When testing for gestational diabetes, the results to indicate a normal blood sugar level are below:
- 95 mg/dL (before eating)
- 180 mg/dL (one hour after eating)
- 140 mg/dL (three hours after eating
Normal Blood Sugar Level for an older adult 65 years and over
As we age, we are at risk of developing many health-related conditions, including diabetes. In fact, the incidence of newly diagnosed diabetes is highest among those aged 65 to 79 years. However, the target blood sugar levels to adequately manage diabetes alongside other health and wellbeing factors may differ for older adults compared to younger adults and is dependent on their health status.
For example, for someone who is relatively healthy with no or few chronic health conditions and normal cognitive functioning, a fasting blood sugar level of 90–130 mg/dL (or 7.5% or less on the A1C test) is normal. However, for many older people who are managing multiple chronic conditions or experiencing cognitive impairment, it can be difficult to maintain this blood sugar level at all times. So the targets are relaxed somewhat out of practicality to 90 to 150 mg/dL (8% or less on the A1C test). For someone at the end of their life with chronic illness or severe cognitive impairment, a reasonable target is 100-180 mg/dL (8-9% on the AC1 test).
Screening for Diabetes
You should consult your doctor if you are concerned about your blood sugar levels. The American Diabetes Association recommends screening for diabetes if you are:
- Overweight – that is, if you have a body mass index higher than 25 (23 for Asian American people), regardless of age. If you have additional risk factors, such as high blood pressure, abnormal cholesterol levels, a sedentary lifestyle, a history of polycystic ovary syndrome or heart disease, or a close relative with diabetes, you may be at risk of diabetes and should get a blood sugar test.
- Adults 45 years and older – you should have a blood sugar screening test for diabetes once every three years
- A female who has previously had gestational diabetes – you should have a blood sugar screening test for diabetes once every three years
- Prediabetic – if you have previously been diagnosed with prediabetes, you should get a yearly test.
Treating Diabetes
If you have any form of diabetes, treatment begins with monitoring your blood sugar levels carefully. Many people with Type 2 diabetes successfully manage their blood sugar levels with healthy dietary changes that minimize sugar and carbohydrate consumption and add exercise to their daily lives. Sometimes, they also have to take medication or rely on insulin replacement to manage their blood sugar levels.
If you have Type 1 diabetes, you need insulin replacement therapy to control the blood sugar level in your body. Replacement therapies consist of doses of insulin delivered via injections or through an insulin pump. You can also use oral medications in combination with insulin therapy for better results, but you cannot take insulin itself orally.
Resource Links:
- “Blood Sugar Test” via MedlinePlus
- “Diabetes” via Mayo Clinic
- “Diabetes” via National Health Service
- “High blood sugar (hyperglycaemia)” via NHS
- “Diabetes Tests” via Centers for Disease Control and Prevention
- “Blood Sugar Level Ranges” via Diabetes
- “Progression to type 2 diabetes in women with a known history of gestational diabetes: systematic review and meta-analysis” via British Medical Journal
- “Diabetes: What You Need to Know as You Age” via Johns Hopkins Medicine
- “Diabetes in Older People” via National Institute on Aging
- “Manage Blood Sugar | Diabetes” via Centers for Disease Control and Prevention
