Two men smiling while jogging and discussing the effect of exercise on blood sugar

What is the effect of exercise on blood sugar?

Written on November 28, 2022 by Theresa Vuskovich, DMD. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Table of contents

You know exercise has countless health benefits, but do you know how exercise affects blood sugar levels? If you have diabetes, blood sugar levels are the center of your universe. Exercise can have significant effects on your blood sugar during and after exercise.

If you are an adult with type 2 diabetes, here's what you need to know about the effect of exercise on blood sugar.

1. Exercise can lower your blood sugar levels

If you have diabetes, exercise is beneficial but can also complicate your blood glucose management. Before we discuss how exercise lowers your blood sugar, let's review the basics of type 2 diabetes. Type 2 diabetics have an inadequate supply of insulin, a hormone responsible for transporting glucose (i.e., sugar) from the blood into cells. Having type 2 diabetes results in insulin resistance, meaning your body no longer responds normally to insulin, and your blood sugar levels rise. High sugar levels can affect your health now and in the future. High sugar levels can cause heart disease, blindness, kidney failure, and nerve problems [8].

Now that we have reviewed the basics of type 2 diabetes, let's explore why exercise lowers your blood glucose levels. When you perform an aerobic exercise (i.e., "cardio"), regardless if you have type 2 diabetes, your body uses the fastest glucose source, the sugar in your blood, to power your muscles during exercise. When you perform cardio, your muscles absorb 5x more glucose than at rest, reducing your blood sugar levels [5].

2. Exercise can raise your blood sugar levels

In contrast to aerobic activity, anaerobic activity (e.g., resistance or strength training) can raise your blood glucose levels [12]. This is often called postexercise hyperglycemia. Increased blood sugar levels are most common following high-intensity interval training (HIIT) or resistance exercise [12]. The rise in blood sugars is due to the release of stress hormones (e.g., adrenaline), which causes your liver to release more sugar into the blood. An aerobic cooldown (e.g., walking) is recommended to minimize elevated blood sugar levels [12].

3. Exercise improves your insulin sensitivity

As a result of exercise, your body is more sensitive to insulin levels, which makes it more efficient at removing sugar from the bloodstream [10, 11]. It is unclear exactly why exercise improves insulin sensitivity, but some research studies have found that the improvement in insulin sensitivity is primarily due to changes in the transcription process, a part of the molecular pathway through which genes make proteins [9,13].

4. Exercise type can affect your blood sugar levels differently

As previously mentioned, your blood sugar levels vary depending on the type of physical exercise and exercise intensity. Aerobic exercise tends to lower blood sugar levels, while anaerobic exercise tends to increase blood sugar levels. Let's explore which exercises are aerobic and anaerobic, as well as the activity recommendations from the American Diabetes Association (ADA) [2,5].

The ADA recommends the following exercise regimen for people with type 2 diabetes [2,5]:

  • 150 min/week of aerobic activity, such as brisk walking
  • 3 days/week of aerobic activity and no more than 2 consecutive days without exercise
  • 2−3 sessions/week of resistance exercises on nonconsecutive days
  • 2 sessions/week of flexibility sessions involving the whole body

You can stay motivated and avoid injury if you practice different exercises. Here are the four types of exercises and recommendations from the ADA [5,7]:

  • Endurance: cycling, swimming, walking, and yard work
  • Strength: lifting weights, carrying groceries, and using a resistance band
  • Balance: Tai Chi, standing after sitting for a long time, and standing on 1 foot
  • Flexibility: yoga and stretching

These guidelines help control type 2 diabetes blood sugar levels, but there are other factors to consider in addition to these guidelines. A healthy diet and moving throughout the day can also help you control your blood sugar [2,5]. Nutritionists often recommend a Mediterranean diet for individuals with type 2 diabetes [3].

Even though regular exercise is recommended for most adults with type 2 diabetes, it is important to consult a healthcare professional to determine your best exercise regimen.[5,12] Before recommending an exercise regimen, your healthcare professional will review the following information [12]:

  • Medication
  • Body weight
  • Fasting glucose level
  • Blood pressure
  • Blood oxygen saturation
  • Other diseases

It is important to discuss changes in your exercise regimen with your healthcare provider when one of these factors changes. Now that we have reviewed many of the short-term effects of exercise on blood sugar, let's explore one of the long-term positive effects of exercise on blood sugar levels.

5. Exercise improves your ability to control sugar levels over time

Although blood sugar levels may fluctuate briefly after exercise, exercising can also improve your ability to control your blood sugar levels over time. If you have type 2 diabetes, you know about the A1C or HbA1c test. You use this test to determine the amount of glycated hemoglobin (HbA1c) in your blood. HbA1c is the component of your red blood cells (RBCs) that attaches sugar, so the test tells you how many of your RBCs are sprinkled with sugar.

The A1C test measures your blood sugar levels over the past 3 months. Knowing your A1C results is important to ensure you avoid the long-term complications of diabetes, such as heart and nerve problems [6]. Exercise is also an important part of controlling the levels of HbA1c. A meta-analysis, a study of multiple trials, found moderate increases in physical activity reduced HbA1c [4].

Overall, exercise improves blood sugar control and diabetes management. Always check with your healthcare provider before beginning a serious exercise routine. Exercising with type 2 diabetes requires knowing your blood sugar levels. Everlywell offers an at-home HbA1c test to help you check your blood sugar levels over the past 3 months. Visit Everlywell's product page to discover more convenient, at-home wellness tests.

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References

  1. American Diabetes Association Professional Practice Committee. 2. Classification and diagnosis of diabetes: Standards of Medical Care in diabetes-2022. Diabetes Care. 2022;45(Suppl 1):S17-S38. doi:10.2337/dc22-S002. URL
  2. American Diabetes Association Professional Practice Committee, Draznin B, Aroda VR, et al. 8. Obesity and weight management for the prevention and treatment of type 2 diabetes: Standards of Medical Care in diabetes-2022. Diabetes Care. 2022;45(Suppl 1):S113-S124. doi:10.2337/dc22-S008. URL
  3. American Diabetes Association. 3. Foundations of care and comprehensive medical evaluation. Diabetes Care. 2016;39 Suppl 1(Supplement_1):S23-35. doi:10.2337/dc16-S006. URL
  4. Boniol M, Dragomir M, Autier P, Boyle P. Physical activity and change in fasting glucose and HbA1c: a quantitative meta-analysis of randomized trials. Acta Diabetologica. 2017;54(11):983-991. doi:10.1007/s00592-017-1037-3.2. URL
  5. Colberg SR, Sigal RJ, Fernhall B, et al. Exercise and type 2 diabetes: the American College of Sports Medicine and the American Diabetes Association: joint position statement. Diabetes Care. 2010;33(12):e147-e167. doi:10.2337/dc10-9990. URL
  6. Diabetes Prevention Program Research Group. Long-term effects of lifestyle intervention or metformin on diabetes development and microvascular complications over 15-year follow-up: the Diabetes Prevention Program Outcomes Study. Lancet Diabetes Endocrinol. 2015;3(11):866-875. doi:10.1016/S2213-8587(15)00291-0. URL
  7. Four types of exercise can improve your health and physical ability. National Institute on Aging. Accessed November 24, 2022. URL
  8. Goyal R, Jialal I. Diabetes Mellitus Type 2. In: StatPearls [Internet]. StatPearls Publishing; 2022. URL
  9. Iaccarino G, Franco D, Sorriento D, Strisciuglio T, Barbato E, Morisco C. Modulation of insulin sensitivity by exercise training: Implications for cardiovascular prevention. J Cardiovasc Transl Res. 2021;14(2):256-270. doi:10.1007/s12265-020-10057-w
  10. Sylow L, Kleinert M, Richter EA, Jensen TE. Exercise-stimulated glucose uptake - regulation and implications for glycaemic control. Nat Rev Endocrinol. 2017;13(3):133-148. doi:10.1038/nrendo.2016.162. URL
  11. Ross R. Does exercise without weight loss improve insulin sensitivity? Diabetes Care. 2003;26(3):944-945. doi:10.2337/diacare.26.3.944. URL
  12. Turner G, Quigg S, Davoren P, Basile R, Mcauley SA, Coombes JS. Resources to Guide Exercise Specialists Managing Adults with Diabetes. Sports Medicine - Open. 2019;5(1). doi:10.1186/s40798-019-0192-1. URL
  13. Wojtaszewski JF, Nielsen JN, Richter EA. Invited review: effect of acute exercise on insulin signaling and action in humans. J Appl Physiol (1985). 2002;93(1):384-392. doi:10.1152/japplphysiol.00043.2002. URL
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