How to Manage Blood Glucose Levels During Exercise

Understanding Your Blood Sugar levels when Exercising 

The effect that exercise and physical activity levels has on your blood sugar can entirely depend on how long you are active for and many other factors. Physical activity can lower your blood glucose levels up to 24-48 hours after your workout, which increases your insulin sensitivity. 

In order to become familiar with how your blood glucose levels respond to exercise it is extremely important that you are checking your levels often- before and after exercise. Adapting to different activities and exercises can also allow you to see how your body responds to the increase in activity levels, making it easier to prevent blood glucose levels from going too high or low. 

Making sure your glucose levels are in a healthy range pre-workout is essential. It is generally ok to begin exercise if your glucose levels are between 100mg/dl and 250 mg/dl. Should they be below 100mg/dl, you’ll need to consume a snack prior to starting your exercise. 

Hypoglycaemia Within Physical Exercise 

For diabetics, people taking insulin are more at risk of developing hypoglycemia when taking part in physical activity. Adjusting your insulin and carbohydrate intake around exercise is essential to allow higher energy levels from carbohydrates to sustain you during exercise, or a reduction in insulin to prevent hypoglycemia from occurring during exercise. Please seek medical advice from a professional in relation to medication change prior to exercising. 

Other ways to avoid low blood glucose levels pre-or-post exercise can include:

  • Not exercising at least 2 hours before bed to allow you time to check your glucose levels post-workout.
  • Skipping alcohol before or right after you work out. 
  • Avoiding sitting in hot baths or steam rooms after exercising. 
  • Being physical once or twice a day.

Symptoms of hypoglycaemia that are not normally considered to be effects of exercise can include:

• Confusion or feeling delirious. 

• Blurry or impaired vision. 

• Tingling and numbness in lips, fingertips, and toes. 

• A lack in coordination, affecting physical activity. 

Follow the 15-15 rule 

Dealing with hypoglycemia during exercise can be done through a method called the “15-15 Rule.” 

Check your blood glucose levels as soon as you feel the symptoms of hypoglycaemia. If you see that your levels are below 100mg/dl then consume 15-20g of fast acting carbohydrates to raise your glucose levels. This can include:

• 4 glucose tablets (4g per tablet) 

• 1 glucose gel tube 

• 1/2 cup of orange juice or regular soda

• 1tbsp of honey or sugar 

Check your glucose levels again after 15 minutes of digesting these carbohydrates. If they are still below 100mg/dl,  repeat the process again until your glucose levels begin to rise. 

Controlling Blood Glucose Levels Pre-and-Post Workout Through Diet and Exercise 

The number one rule for controlling your glucose levels through diet is by getting into a routine. Some people may find it easier to manage their blood glucose levels if they eat at the same time each day. Making a note of what foods you are eating, especially when consuming carbohydrates allows you to have an idea of how these foods affect your glucose levels when eaten pre-or-post workout. 

When looking at carbohydrates, it is important to look at the glycemic index (GI) as this is the rate at which carbohydrates are processed in the form of glucose within the bloodstream. The higher the number, the quicker your glucose levels will rise. Opting for low-GI foods can allow a slower digestion of glucose into the bloodstream with the aid of fiber to sustain energy levels over a longer period of time. These include:

• Dried beans legumes

• Oatmeal 

• High fibre fruits 

• Non-starchy vegetables 

Making exercise part of your daily routine, especially aerobic activities like walking or cycling will get your heart pumping. You should aim to be active for a minimum of 30 minutes per day, 5 days a week, and slowly introduce resistance workouts into your routine to strengthen the muscles within the body and allow glucose stores to be used during recovery. 

Finding the right time to exercise helps keep blood glucose levels low all day, and by finding that schedule that best suits your lifestyle helps you towards leveling off your glucose levels. Exercising early mornings, before work, or at lunchtime can boost productivity levels and lower stress levels. These times can avoid a rise in glucose levels as they are away from a working environment. 

Gino Fasolino
Diabetic Care and Management Mentor and Level 3 Personal Trainer. Managing glucose levels using fitness, nutrition, lifestyle and weight management techniques.

Black and Diabetic: How I reduced my Blood Sugar Naturally and Lost 90lbs.
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