With type 1 diabetes, my body does not produce insulin and, therefore, cannot regulate my blood sugar levels. Without that mechanism, my body can’t, by itself, convert the food I eat into energy. That’s why I have to take insulin.
I usually describe it as a scale with food on one side and insulin on the other. I need to find the equilibrium between the two by injecting just the right amount of insulin per grams of carbs I eat, taking into account how much energy I think I will burn off during the next few hours. And yes, that can be just as tricky as it sounds.
What my fitness lifestyle has taught me
Interestingly, adopting a consistently active fitness lifestyle these last few years has helped me tremendously with finding that elusive carb/insulin balance.
For me, it all comes down to the knowledge I have gained by developing my meal plans. As I started to design meal plans for myself (and others), I got more knowledge of portion sizes and, most importantly, nutrient values. And I can tell you, the power of knowing what’s actually in the food you put in your body is enormous! Not only do I now have the knowledge to effectively design meal plans that can get me to my fitness goals, I also know exactly how to dose my insulin for each meal.
The insulin and workout balancing act
Through some trial and error, I have finally been able to understand how my body reacts to different kinds of exercise. We are all different, and I know that my experience won’t be directly applicable to everybody else, but the methodology I use should be directly transferable.
There is a huge difference between how cardio and resistance training (lifting weights) affect my blood sugar, so I have to treat each differently.
I always keep a written log of my sugars, food and exercise for the first week whenever I change my routine in the gym. That way I can understand how my body react and be prepared.
For example, I have learned that I always need to have a minimum of ½ a unit of active insulin in my body before a resistant training session, to ensure that my sugars don’t skyrocket (heavy resistance training can sometimes make your body release adrenaline, which makes your sugars rise).
Most of the time, however, resistance training won’t actually impact my sugars very much during the workout (unless I have too little or too much insulin on board), but it does lower my insulin need for about 12 hours after the workout. Since I mostly train at night, I will reduce my nighttime basal slightly on workout days.
Overall, I have found that keeping my sugars in the generally recommended range is optimal for working out. You might be tempted to run your sugars high to avoid those nasty lows during a workout, but you won’t get the best workouts out of that. I prefer to start a workout with my blood sugar level somewhere between 120 and 160 mg/dl (6.5-9 mmol/L). That doesn’t mean that I won’t work out if I’m closer to 200 mg/dl (11 mmol/L). I will just take a little insulin and get cracking.
I usually test my blood sugar just before starting the workout, sometimes during (after 30 min), and after. I do get it wrong sometimes, but that’s ok, as long as I learn and use that knowledge to adjust my behavior.
When doing cardio, my sugars will decrease if I walk or do low-intensity cardio, but stay flat when jogging. It’s a little mystifying that a jog won’t really impact my sugars (and this is not the case for everyone), so you need to test how you react to different types of cardio.
I will usually try to keep my sugars a little higher for cardio than for resistance training, just to ensure that I won’t go low. Optimally, I would like to be around 140 mg/dl (8 mmol/L) when starting out, with no more than 1 unit of active insulin on board. If my blood sugar is a little high, I’ll sometimes take an extra unit before cardio, but my general rule is to not correct until 10-20 min after my cardio is done.
Typically, my sugars will actually start to rise about 10 min. after I finish cardio, as my body is still releasing sugar reserves, but I am no longer burning them.
If my sugars are in the 90’ies (less than 5.5 mmol/L), and I have more than 1 unit of active insulin on board, I simply won’t do cardio. It’s just not worth it since I know I’ll crash. You can of course always carb up, if you really want to do the cardio session, but eating a bunch of calories just so you can burn them off again is not really my thing (I prefer lifting weights anyway 😀 ).
What to eat around workouts
I don’t consume carbs during exercise. I know it’s often recommended, but it’s not my preference. I make sure to have a good quality carb and protein meal about 30-60 min. before my resistance training sessions. Good carbs before a workout are anything low glycemic such as oats, sweet potato, and brown rice (I also wrote a detailed post about my favorite healthy carbohydrates).
I’ll usually reduce my insulin by up to 50% for my pre-workout meal, in order to not go low during my workout. If I’m below 90 mg/dl (5 mmol/L) when getting to the gym, I’ll have a piece of fruit or a fruit bar before I get started. After my workouts, I’ll have a banana and a protein shake. The banana is key. It’s a great post workout carb and, combined with the protein shake, it will help your body repair and grow muscle.
If I’m doing cardio, I usually don’t eat after the workout, unless my sugars are on the low side.
As I wrote earlier, not all diabetics react the same way to working out, so it’s important that you spend a little time testing what works for you and create your own guidelines. Here are a few ideas for how to figure out what the right balance of food and insulin around workouts is for you:
- Create (or have me create) a meal plan and track your sugars for minimum a week to understand how your sugars react to certain foods
- Start working out, and now also track your sugars before, during and after workouts (be aware that working out can impact your insulin sensitivity for up to 12 hours)
- Write everything down, so you can start looking for patterns.
- Find what works for you, use the guidelines above as well as common sense, and you’ll get it down eventually
In my next post, I will talk about the pros and cons of using a CGM (Continous Glucose Monitor).
Remember to always seek the advice of your physician or other qualified health provider before beginning any nutrition or exercise program.