Fitness is one of the most amazing tools to help Type 1 diabetics manage blood sugars. Being active increases insulin sensitivity, speeds up metabolism, helps maintain a healthy weight and does wonders for our mental health. However, a lot of T1Ds experience difficulties with managing blood sugar levels during and after training. This blog article discusses some common and not-so-common struggles with managing BGs through training and physical activity.
To set the base, we need to understand that different types of training affect us differently. For a full breakdown of what those types are and how each one affects us see the video below. In short, cardiovascular training drops blood sugars immediately; HIIT and resistance training raise blood sugars in the moment, but will cause a rapid drop post training and increase insulin sensitivity for the next 12-48 hours.
Let’s dive in and unpick some of the most common challenges and what to do to deal with them or, better, prevent them.
The Classic Scenarios:
1. Hypos During Cardio
This is a super-common phenomenon that happens due to an increased glucose uptake by our body during exercise. Our muscle contractions and all activity is fuelled by glucose, and this means that we will require less insulin during exercise. 3 ways to prevent this are either to (1) decrease basal rate prior to training (suspend about an hour before – for pump users only), (2) to have some fast-acting carbohydrates as a snack prior to activity, or (3) to sip on some juice or a sugary drink throughout the cardio workout to top up the levels of glucose in the body.
2. Hypers During Resistance Training
Our body releases stress hormones, such as cortisol and adrenaline during resistance and explosive training. These hormones raise our blood sugars. These spikes need to be dealt with very carefully, as we are more sensitive to insulin during any kind of activity. You might need extra insulin to prevent that spike from training, if it is a reoccurring event, but the dose to deal with that spike will be about ½ your normal correction for the same number. Only do insulin if you have seen a reoccurring pattern of hypers during resistance or intensity workouts.
3. Hypos with a Workout Shortly After a Meal
Hypos during training after a meal will occur, due to too much insulin on board (IOB). This is very easily corrected: you just need to adjust your bolus for the food. You will need to reduce the dose that you do for the meal, if it is less than 1-2 hours prior to your workout. Not all types of exercise will require a reduction of bolus, and different types may need a different amount of reduction.
The Not-So-Common Scenarios:
1. Hypers when working out after a prolonged period of fasting
When we haven’t eaten for a prolonged period of time, our body will not have much fuel to use to provide energy for our workout. It is possible that our liver will release a load of glucose into our blood, as an emergency response. This will raise our blood sugars, as there will be no insulin to counteract the glucose. The hyper can be prevented by having a snack with some insulin prior to the workout, so that we don’t starve our body of nutrients and energy, and also get some insulin into us.
2. Over-treating hypos during workouts
We often don’t want to wait around if our BGs went low during a session, and it is easy to just eat everything in sight to rise the levels quickly. However, this is not a good idea, as over-treating is very likely. The best way to manage these hypos is to have a set and measured amount of fast-acting carbs, which you know will get you to a good level, rather than having hypo treats out of the bag. Measure out your carbs and know how much you need to avoid over-treating and ending up high. Have the patience to wait before your BGs come back up.
3. Post-workout BG spikes
Often, for cardio workouts we will reduce our basal rate or have food beforehand. During the workout, our body will actively use the available glucose and keep our blood sugars in range. However, when we stop moving, and the food is still acting or the reduced basal is still there, our blood sugars start to rise, as we are no longer actively utilising the glucose in our blood. This can be prevented by doing additional insulin straight after you’ve finished the workout to prevent the rise.
4. Post-workout BG rapid drops
Rapid drops after a workout will most likely occur during resistance and intensity training. This is due to the action of stress hormones stopping in our body and insulin sensitivity returning back to normal. We have also used up a lot of glucose by this point, and will need to replenish it. The best way is to have a snack shortly after the workout, to re-compensate the glucose used up and prevent a low.