Have you ever felt confused about what normal blood glucose levels should be? Since blood sugar levels are key to overall wellness, it’s essential to track and monitor them to ensure you maintain optimal levels. And as it turns out, these optimal glucose levels will vary for many reasons.
Blood glucose levels will vary among different age groups and at different times of the day. And they fluctuate whether you have diabetes or not! It can be challenging to figure all this out on your own, especially if you haven’t already been monitoring your glucose levels. Read on for a simple guide to understanding what’s “normal” and see the typical blood glucose levels for your age range.
A "normal" blood sugar level varies based on many factors. First, it’s essential to understand precisely what blood sugar actually is. Your body metabolizes carbohydrates into glucose, which is your body’s primary energy source. Your pancreas releases insulin to shuttle glucose into your cells to convert to energy or store as glycogen in your liver and muscles or as fat in adipose tissue. Insulin tightly controls the amount of glucose in your bloodstream. Remember, glucose levels are never a flat line and are influenced by many factors, including:
Typical glucose values are often listed as being in range to help capture any normal fluctuations that may occur. Additionally, for those who have prediabetes or diabetes (characterized by some level of insulin resistance), a normal glucose range may be broader or more lenient. It’s because it also accounts for any damage that may have already occurred in the body that makes a tighter range unrealistic.
Now let’s dive into some specifics on normal levels, based on different age ranges!
Typically, children without diabetes between the ages of 6-12 should have normal glucose readings that look like this:
Parents or caregivers won’t typically be checking a child’s glucose throughout the day unless they have a medical condition. Still, it can be helpful to know what is healthy.
For children with diabetes, the amount of glucose in the blood will fluctuate from when they wake up, based on their activity levels, and before they sleep at night. It’s important to remember that despite all this, glucose should overall stay between 80-180 mg/dL at all times throughout the day.
There are no set guidelines by the American Diabetes Association for typical blood glucose for teens without diabetes. So, the NutriSense Team recommends aiming for the same guidelines for healthy children/adults without diabetes, keeping glucose between 70-140 mg/dL.
For teenagers with diabetes, glucose should stay between 70-150 mg/dL throughout the day. Controlling blood glucose during the teenage years could be more difficult, so maintaining a healthy diet and exercise become even more critical.
We have the most information on what glucose levels should be like for adults since this is the time of life when glucose issues typically arise. You may notice that labs have different reference ranges.
Many labs have a maximum value for typical fasting glucose of 100 or even 105 mg/dL. However, we’re all about optimizing here at NutriSense, and research shows that optimal fasting glucose should actually be between 70-90 mg/dL for adults without diabetes. Research also shows that fasting glucose levels above 90 can lead to an increased risk of cardiovascular disease.
There are a lot of factors that can impact a higher fasting blood glucose value. It’s essential to pay attention to things like what and when you ate the night before, sleep quality and quantity, and stress levels. Also, watch your alcohol intake, note any medications/supplements you’re taking, and monitor your overall physical activity and body weight.
Of course, the expected glucose ranges for adults with diabetes will differ from the glucose ranges for adults without diabetes. The American Diabetic Association also suggests different glucose ranges for healthy adults, adults with prediabetes, and adults with diabetes. Healthy adults without diabetes should keep glucose between 70-140 mg/dL.
According to the International Diabetes Federation (IDF) guidelines, adults with healthy glucose metabolism should stay below 140 mg/dL after meals. Healthy adults with standard glucose tolerance have been shown to remain below 140 mg/dL between 95-99 percent of the time while wearing a CGM. Spikes above 160 mg/dL at all can be problematic. They can indicate reduced insulin sensitivity, an increased risk of diabetes, and impaired beta-cell function. Remember, most healthy people will see a peak glucose value within 30 minutes of eating.
Wondering where prediabetes factors into all of this? The ADA classifies prediabetes fasting glucose levels above 100 mg/dL and up to 125 mg/dL and a two-hour postprandial level between 140-199 mg/dL. It’s usually diagnosed with an oral glucose tolerance test. An A1C between 5.7-6.4 percent is considered a prediabetic level.
Diabetes is typically diagnosed after two repeat fasting glucose tests above 125 mg/dL or a two-hour reading above 200 mg/dL after an oral glucose tolerance test. Additionally, an A1C above 6.5 percent is considered a diabetic level. Diabetes is also diagnosed if a random blood sugar check at any time of the day is above 200 mg/dL.
Let’s spend a minute discussing the average levels for older adults, by which we mean over the age of 65. Those who do not have diabetes may be held to the same glucose range as healthy younger adults, keeping glucose between 70-140 mg/dL during the day.
For older adults with diabetes and comorbidities or severe diabetes symptoms like neuropathy, kidney damage, or retinopathy, the recommended glucose threshold, and A1C values may be more lenient. It will all depend on how much damage has been done to the pancreas.
While there are ways to track, monitor, and determine whether you have high blood sugar, you may not always know when you’re experiencing it. Often, there are no warning signs until your levels rise much higher than the expected range.
For example, adults with prediabetes may not realize they have this condition based on symptoms alone. However, here are some classic symptoms of high blood sugar that may occur:
It’s easy to attribute these symptoms to other causes, some as seemingly routine as feeling thirsty or getting a slight headache! That’s where wearing a continuous glucose monitor (CGM) can be invaluable. You may often be able to connect these symptoms to blood glucose spiking throughout the day when you’re monitoring your levels with a CGM.
There are many ways to reduce higher glucose readings that are practical and can be done each day! Here are a few tips from our dietitian, Liz McKinney:
When glucose drops below 70 mg/dL, this is known as hypoglycemia, and it’s associated with symptoms like:
When blood sugar drops <70, accompanied by symptoms, eat 15 grams of quickly absorbing carbs (like apple juice or a glucose tablet), then wait 15 minutes for your glucose to rise.
Once your glucose returns to normal levels, it can help to eat a protein or fiber-focused meal to prevent future dips. McKinney suggests unsweetened Greek yogurt with berries or one to two hard-boiled eggs with sliced avocado on a slice of whole-wheat toast.
If you eat a low carbohydrate diet, seeing your glucose dip <70 may not be a cause for concern. It’s because your body may already be accustomed to lower baseline glucose. In this case, it’s essential to monitor for symptoms and make sure glycemic variability is even during the day.
It’s important to note that no governing body has established exactly what 24-hour glucose using a CGM should be, but this is an area of ongoing research! We know that using the CGM to track glycemic variability offers insight into the swings in glucose throughout the day that are missed in a lab value or A1C.
CGM devices measure interstitial glucose levels (glucose from the fluid between cells). In contrast, a blood test measures glucose in the blood/plasma. While interstitial glucose and blood/plasma glucose levels are correlated, they are different measurements, so diagnoses are not made while wearing the CGM.
To find out about this and much more, sign up for one of the programs at NutriSense! Using a continuous glucose monitor can help you learn more about your body and address and prevent various health issues. With a NutriSense subscription, you can use these continuous glucose monitors with an innovative app that tracks your blood glucose levels in real-time! There’s also a team of registered dietitians to help you read and understand the data.