What is the effect of exercise on your glucose levels?

Why do some workouts raise glucose while others lower it? We break down the short- and long-term benefits of exercise on your glucose levels 

You're probably aware of how important exercise is for longevity, physical and mental well-being, and how it can help with weight loss. 

But did you know that regular exercise has tons of benefits for your metabolic health? Some of the key perks include improving heart health, insulin sensitivity, and glucose (blood sugar) control.^1,2 

Routine physical activity also promotes efficient fuel use in the muscles, can help reduce inflammation, and supports healthy blood fat levels (such as cholesterol and triglycerides).¹  

While exercise generally improves metabolic health² and glucose control, you may actually notice a temporary spike in glucose during or after certain types of workouts.  

So, what exactly is going on? Why does some activity lower glucose levels, while others can cause a short-term rise?

Muscle contractions use glucose for energy, so your exercising muscles can take up and use glucose without the need for insulin.

Glucose levels during exercise 

While you’re exercising, glucose levels tend to fluctuate in response to your workout. 

Since muscle contractions use glucose for energy, your exercising muscles can take up and use glucose without the need for insulin.   

At the same time, stress hormones like adrenaline and cortisol signal your liver to release stored glucose into the bloodstream, helping keep your muscles supplied with energy.  

How this process impacts your glucose levels—which you may notice if you’re tracking your glucose with a CGM like Lingo— depends on the type of exercise, its intensity, and whether you've eaten (especially carb-rich foods) before your workout. 

Your individual fitness level can also impact your glucose levels during exercise. If you’re newer to exercising, almost any movement that gets your heart rate up may temporarily raise glucose.  

Higher-intensity workouts require more fuel, and glucose is your body’s quickest source of energy. Intense exercise also triggers stress hormones like adrenaline, which signal the liver to release glucose into the bloodstream.   

Which type of exercise is most likely to spike your glucose?  

Higher intensity workouts—HIIT, heavy weightlifting, sprints, competitive sports—are more likely to spike your glucose temporarily because your body demands more fuel and uses glucose as the fastest source of energy.  

These workouts also trigger a healthy stress response, temporarily raising hormones like cortisol and adrenaline in addition to glucose. 

In this case, a glucose spike is a good thing. It’s an example of hormesis, in which short-term stress enables long-term adaptation. Like how exercise spikes your heart rate and blood pressure temporarily but provides heart health benefits in the long run. 

This increase in blood glucose may last for an hour or so after you’ve finished exercising.³ It will eventually return to normal levels with the help of insulin working to lower blood glucose levels and restore glycogen in muscles.   

Walking and other low- to moderate-intensity exercise (think: what you can do while carrying on a conversation like a leisurely bike ride, rowing at a slow pace, or using an elliptical) are more likely to lower blood glucose levels temporarily. 

Relative to higher intensity exercise, low- and moderate-intensity types of exercises don’t have as high of an energy demand but do help your muscles absorb more glucose, which is why we recommend walking after a meal.⁵ 

Glucose levels after exercise 

Ever notice increased glucose levels with intense exercise, even after you’ve finished your workout? There’s a scientific reason for that.

After exercise, especially intense workouts like HIIT, the body is still working hard to restore normal metabolic function.

This recovery phase is known as EPOC (Excess Post-Exercise Oxygen Consumption), often referred to as the afterburn effect. During this time, your body uses additional oxygen and energy to repair tissues, replenish fuel stores, and return to a resting state.⁶ 

As part of this process, your body continues to use glucose as a fuel source, and your muscles remain more sensitive to insulin, which helps shuttle glucose into cells more efficiently.⁷ 

You may then experience lower overall glucose levels in the 24-48 hours following your workout, as your body maintains heightened insulin sensitivity. (7,3) 

This is one reason why regular exercise can help lower fasting blood sugar levels—a key marker of long-term glucose control and metabolic health—and why routine exercise is recommended to manage glucose levels and help prevent certain chronic health conditions.⁸ 

After exercise, especially intense workouts like HIIT, the body is still working hard to restore normal metabolic function.

You may experience overall lower glucose levels in the 24-48 hours after a hard workout as your body remains more sensitive to insulin.⁴   

Improving your glucose levels with exercise 

How can exercise/movement improve my glucose? 

Moving your body after eating carbs can help put that glucose to work and avoid a spike.^{9, 5} Some lower-intensity activities that can help reduce glucose levels in the short term include going for a brisk walk, leisurely bike ride, taking the stairs, or 5-10 minutes of bodyweight exercises like calf raises or air squats. 

After a hard workout like HIIT, you may notice lower glucose levels in the 24-48 hours afterwards thanks to the afterburn effect (EPOC).⁴  

Over time, routine exercise also improves your glucose by increasing insulin sensitivity and building and maintaining muscle, which is the primary user of glucose. 

How often should I exercise to improve my glucose?  

The Physical Activity Guidelines for Americans recommend at least 150 minutes of moderate-intensity activity, 75 minutes of vigorous activity, or a mixture of both each week.  

It also recommends muscle-strengthening activities 2 days per week and to reduce extended periods of sitting.¹⁰  Following this guidance can help improve your glucose levels. 

Does it matter what time of day I exercise? 

Whatever time you can fit in exercise is the best time.  

While some research shows afternoon or evening exercise may be more effective than morning exercise to improve glucose control, other studies have found that morning training could provide additional benefits compared with evening exercise as it relates to changes in burning calories and appetite regulation.¹¹

For example, if you do an intense workout in the morning, your body may do a better job at regulating glucose later in the day as you remain more sensitive to insulin (EPOC). This could give you more flexibility if you plan to eat out or have a carb-heavy meal later on.  

Alternatively, exercising later in the afternoon or evening after a meal can help your body use the glucose from that meal and reduce the likelihood of a spike. Keep in mind that  intense exercise too late in the day, specifically within an hour of bedtime, could impact your ability to fall asleep.¹² 

How can I measure my glucose levels during exercise? 

Continuous glucose monitors (CGMs), including Lingo, help you track your glucose with real-time feedback. Since Lingo allows you to manually log exercise and meals, your individual glucose data can help you see how different types of exercise and meal timing impact your glucose levels.

Plus, Lingo can sync with Apple® Health. So if you track your workouts with a wearable device that captures exercise data in Apple Health (like an Apple Watch), that information will automatically log in the Lingo app without having to manually add it. 

Lingo helps you track your glucose data with real-time feedback. You can manually enter exercise into Lingo or sync with Apple Health.

A final note from Lingo 

Low- to moderate-intensity exercise (e.g. walking) lowers glucose, and higher intensity exercise (e.g. HIIT) raises glucose in the short term. However, this temporary rise in glucose is beneficial for your metabolic health in the long run.  

All exercise supports your metabolic health because it improves insulin sensitivity and glucose regulation over time. Furthermore, exercise reduces stress, which has a positive impact on glucose.¹³ Overall, people who exercise regularly have a higher quality of life and better health outcomes. ¹

Lingo provides you with real-time glucose data. Armed with this information, you can understand how exercise, meals, and other lifestyle habits impact your glucose levels, and thus affect your energy and performance.

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