SPORT, EXERCISE AND DIABETES

Sport and exercise are very good for you for many reasons (even if you don't have diabetes ;-) . However, sports and diabetes present some challenges, and you can read more about that here. But first something about the benefits of sport / more exercise if you have type 1 diabetes:

• You become more sensitive to insulin. That means you need less insulin and glucose regulation becomes easier. This causes fewer fluctuations in your blood sugars and has a beneficial effect on your weight. 
• A lower chance of developing cardiovascular disease. 
• A beneficial effect on your HbA1C and Time in Range.

Exercise also has effects that you should keep a close eye on. For example, with exercise, muscle activity improves blood flow to the subcutaneous fatty tissue. As a result, insulin is absorbed more quickly. That means you have to learn to adjust. The Diabetes team at Diabeter can advise you. 

What does extra exercise do to your glucose regulation?

The body uses more energy during sports and exercise, such as cycling, walking and shopping. This requires extra glucose in the muscle cells. That glucose comes directly from the bloodstream into the muscle cell. This does not require insulin to get the glucose into the muscle cell. Once you exercise, your vessels are opened up to get rid of the heat, so your blood flow goes up. Insulin that is in the subcutaneous fatty tissue (subcutaneous) is absorbed faster because of improved blood flow. As a result, the insulin gets to where it can do its job much faster: faster and more effectively.

If there is not enough glucose available, blood glucose levels can become too low, this is called a hypoglycemia. If you have too little insulin on board during exercise, then your glucose value rises. You speak then of a hyperglycemia. More about this later.

Exercise with diabetes is all about precision

As you may have noticed, it varies from day to day and in terms of types of sport how you end up with your glucose level. This is quite difficult to find a good way of setting it. So it appears that type of sport, the duration and how you as a human being is determined how your glucose is processed. So also how you end up with your glucose values. You do your best to do as agreed, and then you have that hypo or you end up too high. The adjustments needed for sports are not only different for each person, but also for the type of sport and exercise, the duration of the activity and which insulin pump / insulin pen / FGM / CGM you use.

What is useful to know when you are going to exercise or e.g. go shopping?

• You cannot "magic away" the insulin that is already present. If you have diabetes, your body does not respond as well to a lower glucose level via 'counter-hormones' (adrenaline, glucagon, glucocorticoids). In short, you always have 'insulin on board' at a level that can be inconvenient in sports and activity. You are more likely to have a hypo.
• If a sport lasts more than two hours and you have taken the insulin pump off during your exercise, you may also see the glucose level rise. You don't expect this, but the reason is that after two hours the insulin that was still present in your body is depleted. After all, your short-acting insulin works for 2-3 hours. If the pump is stopped longer, the insulin needed to get your glucose into the cells will have run out. As a result, your value will rise instead of fall.
• Regular glucose measurement before, during and after physical activity gives you control: if you know how you sit you can act accordingly or do things differently for the next time, for example.
• Knowledge about the type of sport and what it does to your glucose helps you understand why and how your glucose changes.
• Types of sport and the influence on your glucose levels
• The type of sport has an influence on the course of your glucose values: anaerobic sports have a different effect than aerobic sports. In aerobic sports, you train for a long time with a relatively low intensity. This includes, for example, running, cycling, swimming and skating. In anaerobic sports, you train for a short time at a high intensity. Examples include sprinting and strength training. 

Type of sport determines glucose levels in diabetes

If you're someone who runs or e.g. skates (the so-called endurance sports), you see in the left image that your glucose easily drops. If you play e.g. soccer, then your glucose value can go down as well as up: e.g. in a fitness training your value will go down quickly, but in a more technical training you often see your value increase more easily. This can be seen in the middle picture. The right image shows that if you do a sport in which you use a lot of muscles for short periods of time, such as power sports, the value can actually increase.

The image above shows the same thing, but in a different way: prolonged exercise depletes your glucose supply, increasing the likelihood of lower glucose levels. 

Preventing a hypo during and after exercise

You may know it: after exercising, your blood glucose drops for a while. This is because the glucose supply from muscles and liver is used during exercise and your body must first replenish it. It is possible that you still long after exercising, even to the next day, a low blood glucose. It is important to check blood glucose regularly after exercise, for example after one hour and after two to three hours, and eat extra if necessary. The insulin amount will also need to be adjusted. After all, you need less insulin than normal to achieve the same result because your insulin sensitivity increases. 

A number of Diabeter tips & tricks: 

• Reduce insulin before, during and after physical activity: If you use an insulin pump, you can adjust the basal insulin. Consult with your treatment team to get tailored advice.  
• Pre-measurement. Your glucose level before exercise is important. If it is too high (e.g. above 20 mmol/l), you may have an insulin deficiency and exercise will not be successful. Your muscles will acidify more easily because they don't get enough glucose and the build-up of muscle mass will fail, while you're working so hard for it. In other words: this sport moment will not improve your condition or lead to more muscle mass. If your insulin level is too low before exercise (lower than 3.9 mmol/l), you have too much insulin on board before exercise. Now you can't just start exercising! The insulin present in your body is not just gone. However, you can compensate the effect of insulin by taking fast carbohydrates (dextrose) and for the hours afterwards some long-acting carbohydrates (sandwiches, for example). Consult with your treatment team for tailored advice and/or consult your Therapy Mail. 
• Make sure your coach (and your teammates) know that you have type 1 diabetes. Telling them about your diabetes will not only help you, but also your coach in your optimal performance. But perhaps most importantly, it will help you to understand. 

Top-class sport and diabetes: yes, it's possible!

If you've read all this and think about what you have to do to keep your glucose level within the limits, your heart may be sinking. But there are many people with diabetes who do sport, even top-level sport is one of the possibilities. Here are some inspiring stories:

First goal at World Cup by footballer with diabetes 

Valerie Magis, top hockey player: "I want to be an example for people with diabetes who also want to reach the top."  

Jan Arie van der Heijden, top footballer: Sport helps you feel fit and it helps your insulin to be absorbed better

Charlotte van der Hoek: Life saving swimming.