How does exercise help keep type diabetes at bay – and what sort of exercise might work for you? Diabetes educator and dietitian CHARLOTTE ROWLEY writes.

If you’re living with diabetes or prediabetes, you’ve probably heard a lot about the benefits of exercise. But there is so much contradictory information out there on the world wide web about what type of exercise you should be doing, how long you should do it for, and the best times of the day. Let’s take a look at how exercise actually impacts your blood glucose levels, if it has any other benefits, and what exercise is going to be best for you. 

Back to Basics 

When we eat carbohydrates these are broken down into glucose, which is absorbed into your bloodstream. We need to move this glucose from the bloodstream into the organs, tissues or muscles of the body, so that it can be used for energy.  To help this process, our body will produce insulin, which helps the glucose move into the organs, muscles and tissues. It’s like a key that opens doors from the bloodstream, letting the glucose go where it’s needed. When we are living with type 2 diabetes, the insulin can’t do its job as easily as it used to, so it’s more difficult to open those doors and get the glucose from the bloodstream into the organs, muscle and tissues. We call this insulin resistance. 

What happens with exercise? 

Exercising essentially opens doors in our muscles to let more glucose in. Some of those doors  rely on insulin to be opened, but not all of them. Exercising increases your glucose uptake into your muscles without relying on insulin. For people with type 2 diabetes, who are resistant to insulin, having more doors which don’t rely on insulin to work is a huge plus! 

The best part is that these no-insulin doors can hang around for hours or days after your exercise is finished. This means, even if you exercised yesterday, you may still have additional non-insulin doors on your muscles helping to take up glucose. 

What type of exercise should you choose? 

There are different benefits to different types of exercise.  

Aerobic exercise (really any “cardio” based exercise that gets your heart pumping) is great for improving your insulin resistance. In just seven days of vigorous aerobic exercise (we’ll come back to how to tell if your exercise is vigorous), you may see improvements in your blood glucose levels.
Aerobic exercise also helps you have maintain a healthy blood pressure and cholesterol level. Even if you don’t lose weight by adding in some more cardio, you’ll likely see the benefits in your next blood test. 

Resistance exercise is any movement that makes your muscles work against something else. This could be body weight training, such as pushups or a dumbbells for your bicep curls. Resistance exercise can also improve your sensitivity to insulin, as well as improving your blood pressure, cholesterol levels, bone density and muscle mass – all important aspects to staying healthy! 

Combining both some aerobic and resistance exercise may be the way to go, with many studies that involve both aerobic and resistance training reporting greater health benefits than doing only one or the other. 

How intense should you go?  

High intensity interval training (HIIT) can be a good alternative to walking for aerobic training. The great thing about HIIT is that it’s often more time efficient, as you’re doing higher intensity work (75-95% of your max heart rate) but for shorter amounts of time. This also has a great benefit on fitness levels, reducing HbA1c and improving insulin sensitivity. 

Starting Exercise: is it healthy for people with diabetes? 

If you’re ready to get more active, you may be feeling a bit worried about if it’s safe for you. Living with diabetes does mean we need to be more conscious of our blood glucose levels, but the effect of exercise will vary from person to person. 

If you’re starting a new exercise program, you may need to (over time) reduce your glucose lowering medication. Working closely with your medical team over your journey is really important. 

1. The safest first step is to get a review from your GP, particularly if you haven’t had your bloods checked for while. After getting your blood glucose levels, cholesterol and blood pressure checked, your GP can give you clearance to get active. 
2. You might want to consider booking in with an Accredited Exercise Physiologist. You may even be able to access this service through your Chronic Disease Care Plan. An exercise physiologist is specifically trained to help people with chronic health condition to move well and become more physically active. They can design you a tailored plan, taking into account your preferences and any injuries you may have.
3. If you have issues with your feet, a trip to the podiatrist may also be a good preparation step. Particularly if you are considering investing in a new pair of shoes for your training, speaking to your podiatrist means you’re getting off to the best start. 
4. Ask yourself if you’re feeling well on the day you start. Check your blood glucose levels. If you’re not well, skip the exercise for the day. If your blood glucose levels are high (particularly, above 16.7mmol/L), we should probably address this before we get moving.  
5. While your exercising, check your blood glucose levels regularly, especially during longer exercise sessions. Every 20-30 minutes, check in on your levels, particularly if the exercise is new to you, you’re increasing intensity or you’re going for longer than usual. Having a hypo kit with you is a great idea, in case your blood glucose levels do drop too low. If this happens, stop exercising immediately to treat your hypo.  
6. Check your blood glucose levels again after you’ve finished exercising, and if you are new to exercise, keep more of an eye on it than usual for about 24 hours after exercise. It’s often a good idea to have a carbohydrate meal or snack planned for shortly after finishing your exercise, and possibly another carbohydrate snack just before bed in the evening, if you are prone to overnight hypoglycaemia. 

Now you have a plan for getting active, it’s time to get active!