The main source of energy for the body is sugar. Muscles, especially, use a lot of sugar when they contract during exercise. Many doctors and dietitians recommend adding exercise to a workout routine to complement the action of medications and keep blood sugars controlled.  But how exactly does exercise lower glucose? How much and what types of exercise do you need? When should you exercise?

These wonderful questions are common ones from the most curious health seekers among us.

Just like medications traditionally need to be taken regularly, exercise must also be part of your daily routine to keep your blood sugars controlled and stable.

So How Does Exercise Work?

There are a few ways that exercise lowers blood glucose:

• Insulin sensitivity is increased, so your muscle cells are better able to use any available insulin to take up glucose during and after activity.
• When your muscles contract during activity, your cells are able to take up glucose and use it for energy whether insulin is available or not. The larger the muscles are, the more glucose they’ll demand and pull out of the blood.  

For this reason, physical activity can lower your blood glucose up to 24 hours or more after your workout by making your body more sensitive to insulin (meaning that if you are building muscle and exercising regularly, typically medication doses would be lower than when you are not exercising).

This is how exercise can help lower blood glucose in the short term. And when you are active on a regular basis, it can also lower your A1C.

The effect physical activity has on your blood glucose will vary depending on how long you are active, the type of exercises you do, your medications, and many other factors, some are listed below:

• Exercise duration (longer duration uses more sugar for energy)
• Exercise intensity (If you’re working faster or with more resistance, your muscles will require more glucose in the moment.  )
• Adding weight (the more strength and power your muscles have, the more glucose they require to be maintained- even when you’re sleeping)

To sum it all up, this means that when you do a lot of aerobic exercise, your muscles use more sugar in that moment, dropping glucse quickly. But when you do a lot of strength-training exercises that build muscle, your muscles will demand just slightly more energy over a longer period of time, lowering your basal glucose even when you sleep! That also means that the more muscle you build, the lower your fasting glucose will likely become. And doing cardio within the 2 hours AFTER meals would be best to reduce risk of glucose spiking after you eat.

Check Your Glucose

Become familiar with how your blood glucose responds to different durations and types of exercise.

Checking your blood glucose level more often before and around 30 minutes after exercise can help you see the benefits of activity. You also can use the results of your blood glucose checks to see how your body to reacts to different activities. Understanding these patterns can help you prevent your blood glucose from going too high or too low, and can also tell you if the amount of exercise you're doing is sufficient to cover what you've eaten and support your medication regimen.

Insulin/GLP-1 and Exercise: Safety Precautions‍

For people using insulin (with or without a GLP-1 medication), exercise can lower blood glucose, so a few safety steps are important:

First, check blood glucose before starting exercise.

• If BG <90 mg/dL, treat with 15–30 g of fast-acting carbohydrate and recheck before exercising.
  
• If BG 90–150 mg/dL, additional carbohydrate may be needed for moderate-to-prolonged exercise (>30 minutes), especially if insulin was taken recently.
  
• If BG >250 mg/dL, check for symptoms and consider postponing intense exercise until levels are lower.
  

After exercising,

• Be aware that delayed hypoglycemia can occur, especially several hours after activity.
  
• A post-exercise snack with protein and carbohydrate may help stabilize glucose (e.g., Greek yogurt with berries)
  
• To reduce the risk of post-exercise lows, avoid alcohol for several hours after activity, especially if exercise was prolonged or intense.
  

GLP-1 Considerations

• GLP-1 medications alone have a low risk of causing low glucose, but when combined with insulin, the usual insulin-exercise precautions still apply.
  
• Because GLP-1s slow gastric emptying, smaller, lower-fat snacks may be better tolerated around exercise.

‍

Questions about getting some food with exercise? Read our other article about fueling for workouts for more tips!