Fuelling Workouts as a T1D

What to eat around training sessions is an ever-popular topic with diabetics. How to get enough energy, but also have good blood sugars during your session? How to perform your best and keep blood sugars in check? Let’s discuss what we can do to help us make the most out of our workouts.

First of all, we should always remember that different types of training affect our blood sugars in different ways. Cardiovascular exercise, such as running, cycling and walking will drop our blood sugars. Strength training will rise our blood sugars. Explosive workouts and HIIT will also rise our blood sugars. These different types of training will require different approaches to achieve optimum performance and blood sugar management.



Cardiovascular exercise lowers blood sugars, which means we require quick carbohydrates to keep sugars up, but also to provide an easy source of energy for our muscles. There are a few approaches to avoid lows during cardio sessions.

Approach 1: A great way to fuel a cardio session would be to eat a snack of 15-20g fast carbs about 20 minutes before your start, which should hold your blood sugars up for 50 minutes to an hour. If the session continues for more than an hour, you would need to top up with more carbs. The amount will depend on how much you have left of your session and what your BG is at the time.

Approach 2: You can reduce your pre-workout meal bolus to avoid a low later. If you are having a substantial meal before you go, you would lower the bolus dose by about 20-50%. This is heavily dependent on the time of day, the individual needs of the body and the type of cardio that you are doing.

Strength training and explosive training both cause a very similar response in our blood sugars. Both types of training put our body in a stressed state, and cause it to release “fight or flight” hormones: adrenaline and cortisol. The liver releases glucose in response to those hormones. This means we would commonly need more insulin to counteract the blood sugar rise with these types of training.

Approach 1: Monitor patters during a number of your training sessions to see how your blood sugar reacts to them. When you have identified a reoccurring spike, you can confidently correct with insulin before it even happens. Start with a small insulin dose, as you will be more responsive to insulin, due to a speed up of blood circulation during exercise. Make sure that overall you are consuming enough calories and protein throughout the day to give you the energy to perform well in your training.

Approach 2: You can have a snack or meal with insulin before your training session. The best choice of snack would be some slow-acting carbohydrates with a source of protein and a little fat to keep blood sugars steady. The insulin on board will act against the spike in blood glucose and help you stay in range, without having to add in more insulin. You may need to reduce your dose for the pre-workout meal/snack, but it is likely that you would need to do the same dose that you would do if you weren’t training afterwards.


You should always check that the training you are doing actually falls in the right category, before taking any actions. Some people might be doing strength training with light weights, which can turn it into a cardiovascular session. So, it is important that you understand which type of training you are actually doing.

Training is possible with T1D, and you can achieve great goals, if you set yourself to it! Do not fear exercise. Exercise is the best thing that you can do for your body, do not let T1D stop you from doing it.



No information in this article is intended as medical advice. Please, consult your diabetic team before embarking on an exercise journey or making changes to your current management.