The Breakdown: Exercising with Type 1 Diabetes

Updated: Jan 17


We all know the day-to-day benefits of exercising, but for type 1 diabetics it's vital. Overall, exercise helps blood sugar level control and minimises the risk of long term complications associated with type 1 diabetes. So, why is it that when I asked 200 Type 1 diabetics if their diabetes led them to avoid exercising, 44% answered yes? Like most things with Type 1 diabetes, there are factors to consider before doing exercise. Exercise can have an immediate effect on blood sugar levels, and this is where the fear stems from. Obviously no-one warms to the thought of collapsing at the side of the road mid-run, but with the right planning this shouldn't be a concern. It’s simple once you get the hang of it, all it takes is a little thought and prep. So, what are the factors you need to consider? 1. What exercise you're about to do 2. When you last took insulin

3. Your current blood sugar

4. The after-effects 5. SWEETS Factor 1: What exercise you're about to do

The rule of thumb that you may have heard of is that cardio or high intensity exercise with low resistance lowers blood sugar. On the other hand, weight training, or low intensity exercise with high resistance increases it.


But how much will cardio-type exercise make my sugar levels decrease, how much will weight-lifting make my sugar levels increase? That ties in with factor number two.

Factor 2: When you last took insulin

If I take insulin one to two hours before doing cardio, the insulin that I have taken usually doubles in effectiveness. Therefore, I will take half as many units as I normally would.


On the other hand, if I plan to do some intense weight training and want to eat something one to two hours beforehand, I won't change my insulin dosage. I will see a slight increase in my sugar levels after doing both of these kinds of exercise. I am aware that some people even increase their insulin dosage before-hand, but I'd always prefer to be safe than sorry.


Now, this is just what works for me and will vary from person to person. Finding what works for you will take some trial and error, but a great starting point is to follow Phil Graham's 3 hour rule.


Phil Graham is a type one diabetic who has just recently won the title of Northern Ireland's fitness person of the year, so it's safe to say he knows what he's talking about. I would definitely recommend his book, 'The Diabetic Muscle and Fitness Guide,' if you're looking to get serious about weight training. He recommends to take your meals and insulin injections three hours prior to exercising. After 3 hours, you will have little to no insulin left circulating around your body which will leave you more in control of your sugar levels. For some pre-workout meal ideas that don't require insulin you can click here. This means that once the third factor is in check, you're good to start exercising!


Factor 3: Your current sugar level

Francesca Rae is currently a world class start athlete in rowing and a type one diabetic. She certainly doesn't let her type 1 diabetes affect her exercise regime, having ran marathons previously too. She recommends always waiting until your sugar level is in a safe range before doing exercise.


But what is a 'safe range’? Francesca says that “before a long cardio session, I'll make sure that my blood glucose is at least 8, whereas when I have a weights session, the adrenaline will spike my levels.” This is because of the stress hormones that heavy weight training releases which raise sugar levels. In these situations, she feels safe with her blood glucose at 6.0-8.0.

She continues that she “refuels quickly after a long cardio session, as afterwards my sugars are likely to go down”, bringing us to factor 4.


Factor 4: The after-effects of exercise

I never leave it too long to refuel after a high intensity workout. I am more sensitive to insulin afterwards so I normally take one unit less than normal. This can differ for you!


If you find your sugar levels a little high after a low intensity, high resistance work out, always consider the fact that once the stress hormones this workout releases have left your body, your blood glucose will decrease. Don't jump the gun and go overboard on insulin, give your body time to react to the workout!


Factor 5: Sweets


I left the most important until last. Never, ever, start exercising without a sugar source within reaching distance. In fact, never leave the house full stop without some type sugar source at hand. (A mini pack of skittles is my go-to).


There is a lot of trial and error when it comes to balancing exercising and type one diabetes, but that shouldn't let it stop you! By using these tips as a guide and remembering your sweets, you really have nothing to worry about. Hope this post has helped. x

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