7 Tips for Managing Blood Sugar During and After Workouts

In the difficult journey to lowering blood sugar levels and reaching a healthy lifestyle, many turn to increasing exercise frequency, finding a balanced diet, and medications like Ozempic and Saxenda to assist in more stubborn cases. Scientific research supports physical activity as a highly effective and simple way to lower blood sugar levels and stabilize glucose responses long-term, even for those living with type 2 diabetes.¹ 

However, if you’ve been wearing your continuous glucose monitor, you might notice a sudden spike or dip in your blood sugar levels during exercise. Fluctuations outside the normal range can lead to complications, including fatigue, mood swings, and impaired cognitive function.² Seeing these sudden fluctuations during physical activity may leave you feeling overwhelmed and confused, causing you to abandon your new exercise routine out of fear of worsening your health. 

When monitoring your blood sugar, it is crucial to remember that not all changes are negative, and spikes, especially while exercising, are for good reason. The key is understanding the differences between unnecessary spikes and dangerous dips and how balancing the types and intensities of exercise during the week is the ultimate strategy for maintaining stable blood sugar levels long term. This article breaks down the reason behind blood sugar changes during exercise, which types of workouts may cause more spikes versus more dips, and tips on how to maintain stable blood sugar levels during workouts so you can use physical activity as an effective tool in blood sugar control, weight loss, and maintaining a healthy, well-rounded lifestyle. 

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Understanding Blood Sugar Changes During Exercise

During workouts, blood sugar spikes primarily occur due to increased energy demands and the release of stress hormones. Our muscles need more fuel to sustain physical activity, prompting the body to release glucose into the bloodstream to meet this demand. Additionally, the stress placed on the body during exercise triggers the release of hormones like adrenaline and cortisol, which can cause blood sugar levels to rise.³ These hormonal responses help provide the energy needed for physical exertion but can lead to temporary spikes in blood sugar levels, especially during intense or prolonged workouts.

Extreme dips in blood sugar, known as hypoglycemia, can occur during workouts due to various factors. One primary contributor is overexertion, where prolonged or intense physical activity depletes the body's glycogen stores faster than they can be replenished. This can cause a sudden drop in blood sugar levels, leading to symptoms like weakness, dizziness, and confusion. Additionally, the body's insulin response to exercise can sometimes be overly efficient, causing excess glucose uptake by muscles and a subsequent decrease in blood sugar levels. Proper nutrition before and during workouts and monitoring blood sugar levels can help mitigate these dips. 

Whether you struggle with dips or spikes during exercise, having unstable blood sugar levels poses several risks to overall health and performance. Both hypoglycemia and hyperglycemia result in symptoms that are dangerous to our health, hinder workout performance, and increase the risk of long-term complications associated with diabetes and cardiovascular disease. Therefore, it is important to understand how different workouts affect your blood sugar levels and the strategies you can implement to stabilize your glucose levels as much as possible during exercise. 

Types of Workouts and Their Impact on Blood Sugar 

Learning how different workouts impact blood sugar levels is crucial for individuals seeking to manage their metabolic health. In terms of blood sugar response, moderate-intensity aerobic exercises typically lead to gradual increases in blood sugar due to sustained energy demands, while anaerobic exercises may cause more immediate spikes and dips due to short bursts of intense effort followed by long rest periods. Here are some examples of aerobic and anaerobic activities and how each affects blood sugar levels.  

Aerobic Physical Activity

1. Running & Jogging: Running or jogging typically involves sustained moderate to high-intensity activity, leading to increased energy demands and a gradual rise in blood sugar levels. This is because the muscles require more glucose to fuel the extended effort.
   
   However, the intensity and duration can influence the magnitude of the blood sugar increase. Shorter, more intense runs may lead to more pronounced spikes in blood sugar, while longer, steady-state jogging sessions may result in a more gradual rise. ‍
2. Cycling: Cycling is another aerobic activity that can impact blood sugar levels. Like running, cycling involves continuous movement of large muscle groups, requiring a steady supply of glucose for energy if working at a moderate intensity. However, increasing intensity by bumping up speed or resistance may lead to a more intense heart rate and more rapid blood sugar spikes.‍
3. Swimming: While swimming can contribute to overall fitness and calorie expenditure, its impact on blood sugar levels may be more gradual than weight-bearing exercises like running or cycling. However, the intensity and duration of swimming sessions can still influence blood sugar regulation, so be mindful of your intensity and effort. ‍
4. Walking: While walking may not lead to as pronounced spikes in blood sugar as more intense activities like running or cycling, it can still help regulate glucose levels by promoting insulin sensitivity and muscle glucose uptake. Regular walking, especially after meals, has aided blood sugar control and reduced the risk of insulin resistance.⁴

Anaerobic Physical Activity

1. Weightlifting: During strength training, muscles use glycogen stored in the body for energy. As a result, blood sugar levels can either remain stable or increase slightly during the workout. After the workout, blood sugar levels may remain elevated as the body works to replenish glycogen stores and repair muscle tissue damaged during exercise. 
2. High-Intensity Interval Training (HIIT): HIIT involves alternating between short bursts of intense exercise and brief periods of rest or lower-intensity activity. This type of workout can lead to significant spikes in blood sugar levels during intense exercise intervals, as muscles quickly burn through available glycogen for energy.
   
   However, during the rest periods, blood sugar levels may drop as the body works to replenish glycogen stores and clear excess glucose from the bloodstream. With the right implementation, HIIT training can be a safe and effective fitness strategy for blood sugar management.⁵ ‍
3. Sprinting: Sprinting involves short bursts of maximal effort, typically lasting only a few seconds to a minute. Like HIIT, sprinting can lead to rapid spikes in blood sugar levels as muscles rapidly deplete glycogen stores for energy. However, unlike longer-duration exercises, such as running or cycling, the impact on blood sugar levels may be more immediate and pronounced due to the high intensity and short duration of sprints.‍
4. Plyometrics: Plyometric exercises involve explosive movements that target fast-twitch muscle fibers. During plyometric exercises, muscles rely on glycogen for quick bursts of energy, leading to rapid depletion of glycogen stores and potential spikes in blood sugar levels. Allowing for proper rest periods and nutrition before activity may help stabilize one’s response to blood sugar fluctuations during higher-intensity activity.⁵  

Aerobic exercises typically lead to gradual increases in blood sugar levels due to sustained energy demands. In contrast, anaerobic exercises can cause more immediate spikes in blood sugar during intense bursts of activity. However, studies show incorporating both anaerobic and aerobic exercise into a fitness routine may be the best strategy for lowering and stabilizing blood sugar levels in the long term.^{6, 7}

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7 Tips for Managing Blood Sugar Levels During Workouts

Effective strategies for maintaining blood sugar levels during workouts are essential for optimizing performance and overall health. By implementing a combination of pre-workout nutrition, hydration, blood sugar monitoring, and post-workout recovery practices, individuals can support stable glucose levels throughout exercise sessions, allowing them to incorporate any type or intensity of physical activity into their fitness routine. 

1. Pre-Workout Nutrition: Consuming a balanced meal or snack containing carbohydrates, protein, and healthy fats before exercise can help stabilize blood sugar levels and provide sustained energy throughout the workout. Opt for complex carbohydrates like whole grains, fruits, and vegetables, which release energy slowly, along with lean protein sources, to support muscle repair and growth.
2. Timing of Meals and Snacks: Pay attention to the timing of your meals and snacks relative to your workout. Aim to eat a meal containing carbohydrates and protein about 2-3 hours before exercise to allow for digestion and energy release. If you're exercising within an hour of eating, opt for a smaller snack that's easy to digest, such as a banana with nut butter or a yogurt parfait.
3. Staying Hydrated: Proper hydration is essential for regulating blood sugar levels during workouts. Dehydration can reduce blood volume and impaired circulation, affecting muscle glucose delivery. Drink water before, during, and after exercise to stay hydrated, and consider replenishing electrolytes lost through sweat with a sports drink or coconut water, especially during prolonged or intense workouts.
4. Monitoring Blood Sugar: Regularly monitoring your blood sugar levels before, during, and after exercise can help ensure they stay within a safe range. This can help you make informed decisions about adjusting insulin dosage, modifying your workout intensity, or consuming additional carbohydrates to prevent low blood sugar episodes.
5. Consuming Carbohydrates During Exercise: For longer or more intense workouts lasting over an hour, consider consuming easily digestible carbohydrates to maintain blood sugar levels and replenish glycogen stores. Options include energy gels, sports drinks, or simple snacks like dried fruit or crackers.
6. Post-Workout Snack: After exercise, refuel your body with a balanced meal or snack containing carbohydrates and protein to support muscle recovery and glycogen replenishment. Aim to eat within 30 minutes to an hour after your workout to maximize nutrient absorption and help stabilize blood sugar levels.
7. Prioritize a Cool Down: Following intense workouts, incorporate a gradual cool-down period to help prevent sudden drops in blood sugar levels. This can include gentle stretching, walking, or low-intensity exercises to gradually decrease heart rate and allow your body to transition from exercise to rest more smoothly.

As always, if you live with diabetes or other medical conditions affecting blood sugar regulation, it is important to consult with your healthcare provider or a registered dietitian for personalized guidance on managing blood sugar levels during workouts. They can help develop a tailored exercise plan, adjust medication or insulin dosage as needed, and provide ongoing support for optimizing blood sugar control and overall health.

Learn More About How to Improve Blood Sugar Health With Signos’ Expert Advice

If you have more questions on improving your health, fitness, and nutrition, seek the expert advice of the Signos continuous glucose monitor and Signos team. A continuous glucose monitor (CGM) can give you the insights to make smarter nutrition and exercise choices. The Signos app provides a unique, personalized program to help you lose weight and reach your health goals. Take this quiz to see if Signos is a good fit for you and reach your goals faster than ever before.

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