Dexcom G6 can help you check how your daily decisions affect your glucose levels

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What Affects Blood Sugar in People Living with Diabetes?

Managing your blood sugar is essential to maintaining your health as a person living with diabetes. Important considerations for blood sugar management include monitoring your blood sugar levels and increasing the time you spend in your target glucose range, to name a few.* Understanding a little bit about the biology behind blood sugar and what affects your blood sugar levels can help you manage your diabetes more confidently.

What is Blood Sugar?

Blood sugar—used interchangeably with the term blood glucose—is the concentration of glucose in the blood. Glucose is a simple sugar molecule that our bodies use for energy. Blood sugar is essential for all of our bodily processes, including brain function.1
How Do Carbohydrates Affect Blood Sugar?
Carbohydrates in the foods we eat are our primary source of glucose, but it can also come from foods we don’t traditionally think of as “carbs.” For example, lactose in dairy products is a sugar that is converted into glucose in the body.2
When we eat and digest our food, glucose enters the bloodstream. Then, as blood sugar begins to rise, the pancreas produces insulin, a hormone that allows glucose to be absorbed into the tissues of the body so it can be used for energy. Insulin is produced by beta cells in the pancreas. Beta cells are a bit like automatic door sensors responding to people walking past: when there is a high concentration of glucose in the blood, beta cells “open up” and to trigger insulin release from the pancreas to help move glucose into the body’s tissues.3 When there isn’t enough glucose, the beta cells “close up” and turn off the insulin release.
In type 1 diabetes, an autoimmune response destroys the beta cells and the pancreas can’t make insulin at all.4 In type 2 diabetes, the pancreas can’t make enough insulin5 or the body doesn’t do an effective job of using insulin, which is called insulin resistance.5,6 In both cases, glucose can’t get into the tissues of the body to be used or stored for energy and instead stays in the bloodstream, resulting in elevated blood sugar levels.
Diabetes and Insulin
Both type of diabetes can cause glucose in the blood to increase, also called high blood sugar or hyperglycemia, because of issues with insulin in the body. According to Diabetes Canada, hyperglycemia is defined as blood sugar levels that are above your target range or higher than 11.0 mmol/L.7

What Can Affect Blood Sugar Levels in Diabetes?

Diabetes results from the body not being able to “automatically” regulate blood glucose levels on its own and so it needs the help of “manual” interventions. These include medication and insulin as well as managing your blood sugar with diet, exercise, and general health maintenance. To find out what might be best for your diabetes management plan, speak to your healthcare provider.
Because people living with diabetes are tasked with managing their blood sugar manually, it’s a good idea to understand what affects blood sugar levels and how to avoid low and high blood sugar. Medication and insulin can help to reduce high blood sugar, or hyperglycemia. But because you’re manually introducing outside insulin or other medications that lower blood sugar —as opposed to relying on your body to automatically adjust insulin levels to blood sugar levels— they can continue working even after your blood sugar is in range, causing your blood glucose levels to drop too low, known as hypoglycemia. This is defined by Diabetes Canada as falling below your target range or less than 4.0 mmol/L.4 Learn more about time in range using continuous glucose monitoring.
It’s easy to feel overwhelmed by all of the things you need to keep in mind as you manage your blood sugar levels, but looking at everyday factors, like diet, activity, and sleep, is a great place to start.

Blood Sugar Levels After Eating and Drinking

We get glucose directly from food and drinks, which is why being mindful of your diet is one of the first steps in diabetes management. Being mindful of what you eat and drink is one part of managing glucose levels and increasing the time spent in your target glucose range.*
Everyone’s body is different, so it’s critical to listen to your body and consult with your healthcare provider at every stage of your glucose management journey. A diet that works well for someone else may not work for you. There are a few basics to keep in mind8 about planning meals around glucose management:
  • Consistency is key. Keep a regular eating schedule9 and ensure that you eat about the same amount of carbs at each meal.10 Consult your healthcare provider to see what meal plan is best for your type 1 or type 2 diabetes management.
  • You don’t necessarily need to avoid carbs. People living with diabetes should aim to get half their calories from carbohydrates. Carb counting is a method you can use to match your carb intake to your insulin dose.8 Your glucose management plan can assist you with what carbohydrates you should avoid and how many carbohydrates you should eat in a day.
  • Plan your mealtimes and stay prepared. To keep your glucose within your target range and avoid hypoglycemia, it’s a good idea to have snacks or fruit juice available when you go out or have a busy day ahead.11
Does Water Intake Affect Blood Sugar?
Water is one of the best beverages for people living with diabetes because it doesn’t contain any carbohydrates or sugar.
Be aware that elevated blood sugar can cause dehydration as the kidneys try to get rid of extra sugar in the blood by excreting it through urine, taking water with it. Consistently drinking water helps prevent dehydration.12
Temperature can also impact hydration. Make sure you’re drinking enough water to keep up with sweat loss. Heat also causes your blood vessels to open up, potentially leading to faster insulin absorption, so it’s smart to monitor your blood glucose if it’s particularly hot out.13
Does Alcohol Increase Blood Sugar?
People often wonder how alcohol affects blood sugar. A small amount of alcohol can actually help increase insulin sensitivity and improve blood sugar management. However, too much alcohol or consuming alcohol on an empty stomach can cause hypoglycemia as the liver prioritizes processing alcohol over maintaining blood sugar levels.14 A few tips to remember before drinking or when consuming alcohol:
  • Talk to your doctor about how to manage drinking alcohol with diabetes15
  • Don’t drink on an empty stomach15
  • Be mindful of the types of alcohol you’re drinking15
  • Consider how many calories are in your drink15
  • Before bed, check your blood sugar level and consider what would be best for you at that time15

Blood Sugar After Exercise

Physical activity can help lower your blood sugar.16 Exercise increases insulin sensitivity in the body, meaning your muscles are better able to use the glucose in your blood. When your muscles contract during activity, your cells can use glucose for energy whether insulin is available or not.16 Be aware of how exercise affects your blood sugar levels and discuss the activities that might be right for you with your doctor.
Blood Sugar Levels and Sleep
Does lack of sleep raise blood sugar levels in people with diabetes? Sleep plays a critical role in your overall bodily functions. Shorter sleep duration is associated with higher A1C in people living with type 1 diabetes17, and even not getting enough sleep in people without diabetes is associated with up to a 30% decrease in insulin sensitivity.18 Practicing good sleep hygiene can positively impact your glucose management.

Monitoring Glucose Levels in Your Body

If you’re experiencing changes in your glucose levels without being sure of the cause, you’re not alone. Monitoring your health is a full-time job, so be compassionate with yourself if you miss clues and cues about your glucose levels once in a while. Whenever there’s an unexpected change in your glucose levels, take note of it in your phone or start a tracking journal.
Each body is different, and it’s wise to learn what triggers variations in your glucose levels. Talk to your healthcare provider about changes you’re experiencing.
Using technology like the Dexcom G6 Continuous Glucose Monitoring (CGM) System can help you keep an eye on your glucose levels over the course of the day and through the night, allowing you to pinpoint when changes happened so you can take action to manage them. Dexcom G6 works to measure your glucose levels and sends that data to a connected receiver or compatible smart device‡ up to every 5 minutes.
Learn more about how Dexcom G6 can make it easier to determine what may cause changes in glucose levels and understand what habits can help you manage diabetes more effectively.
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The information in this article is for informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or health care provider with any questions you may have.
* Talk with your healthcare provider to determine your target glucose range including your personal high and low levels for your target range.
† If your glucose alerts and readings from the G6 do not match symptoms or expectations, use a blood glucose meter to make diabetes treatment decisions.
‡ For a list of compatible smart devices, please visit
1 Mergenthaler P, et. al.. Sugar for the brain: the role of glucose in physiological and pathological brain function. Trends Neurosci. 2013;36(10):587-597. doi: 10.1016/j.tins.2013.07.001
2 Hantzidiamantis PJ, et. al. Physiology, Glucose. StatPearls Publishing. Updated September 20, 2021. Accessed May 15, 2022.
3 Rorsman P, et. al. Pancreatic β-Cell Electrical Activity and Insulin Secretion: Of Mice and Men. Physiol Rev. 2018;98(1):117-214. doi: 10.1152/physrev.00008.2017
4 Type 1 diabetes. Diabetes Canada. Accessed July 18, 2022.
5 Type 2 diabetes. Diabetes Canada. Accessed July 18, 2022.
6 Insulin Resistance. American Diabetes Association. Accessed May 15, 2022.
7 Lows and highs of blood sugar. Diabetes Canada. Accessed July 18, 2022.
8 Basic meal planning. Diabetes Canada. Updated May 16, 2022. Accessed May 15, 2022.
9 Missing Meals? Avoid Dangerous Blood Sugar if You Have Diabetes. Cleveland Clinic. March 9, 2021. Accessed May 15, 2022.
10 Carb Counting. Centers for Disease Control and Prevention. Updated August 10, 2021. Accessed May 15, 2022.
11 Diabeteic hypoglycemia. Mayo Clinic. May 06, 2022. Accessed May 15, 2022.
12 Dehydration & Diabetes. January 15, 2019. Updated January 7, 2022. Accessed May 15, 2022.
13 Change in temperature can affect blood sugar levels. Piedmont. Accessed May 15, 2022.
14 Alcohol & Diabetes. American Diabetes Association. Accessed May 15, 2022.
15 Blood Sugar and Exercise. American Diabetes Association. Accessed May 15, 2022.
16 Diabetes management: How lifestyle, daily routine affect blood sugar. Mayo Clinic. (2022, June 3). Accessed August 17, 2022.
17 Borel A, et. al. Short Sleep Duration Measured by Wrist Actimetry Is Associated With Deteriorated Glycemic Control in Type 1 Diabetes. Diabetes Care. 2013: 36 (10). Accessed May 15, 2022. doi: 10.2337/dc12-2038
18 The Impact of Poor Sleep on Type 2 Diabetes. National Institute of Diabetes and Digestive and Kidney Diseases. March 17, 2021. Accessed May 15, 2022.

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