Physical Fitness: FIVE Tips for Balancing Blood Sugars during Exercise

Physical Fitness: FIVE Tips for Balancing Blood Sugars during Exercise

By Ginger Vieira

1. Understand What Type of Exercise You’re Doing

Jogging and strength-training will both have very different impacts on your blood sugar, even though your heart rate may rise during both. Cardiovascular or aerobic exercise uses glucose primarily for fuel. This means that jogging, running, the elliptical, power-walking, cycling, power yoga, and even gardening—anything that raises your heart rate for an extended period of time—will lower your blood sugar.

Anaerobic activity, like strength-training, sprinting, interval, or circuit training—during which your heart rate goes up, then down, up, then down, and muscle is being broken down—is going to burn more fat for fuel during the activity, but may increase your sensitivity to insulin later in the day while it works to repair and build those muscles. It’s also very common to see your blood sugar rise during this type of exercise, and it’s totally normal (and actually promotes strength-gains, etc.)! More mellow forms of exercise, like casual walking or gentle yoga, aren’t likely to raise your heart rate high enough to actually burn glucose, but that depends on the individual.

2. Control as Many Variables as Possible

When you’re starting a new form of exercise and want to know how that work- out is going to impact your body on a regular day with a “regular” blood sugar, be sure to eat a meal you already know the carbohydrate count of, and don’t start your workout with an out-of-range blood sugar (over 180, under 80).

For example, when I switched from powerlifting in the afternoons to doing bodyweight-only plyometric training first thing in the morning (back when I was still trying to find intense forms of exercise I could do without pain), I set up every workout in the beginning to be as similar as possible so I didn’t have variables like food or high blood sugars (which can require different correction doses before exercise compared to a non-exercising part of the day), and I performed my workout at the same time of day.

I quickly learned that when I wake up first thing in the morning, with an in-range blood sugar, I can perform my bodyweight workout on an empty stomach and I need one unit of insulin to actually keep my blood sugar from rising. For me, this is the ideal time for exercising because my energy is at its highest and I like to get my workout taken care of before I get started with the rest of my day. However, after confirming this experiment, I also tested what happens if I perform this same type of exercise in the afternoon and my insulin needs are exactly the same. That does not mean this applies to all forms of exercise. Just this one. If I want to go swimming in the middle of the afternoon, I’ll create a new experiment and anticipate different results.

3. Treat Your Low Blood Sugars with Only a Few Types of Foods

The food you choose to treat your low blood sugars with does make a difference, not only in the amount of calories you’re consuming but also in how quickly your blood sugar will rise. Using a glass of milk or a peanut butter sandwich to treat a low before exercising is going to give you a lot more calories than you really need and the fat and protein will slow down the digestion, prolonging when your blood sugar will be safe for exercise again. If you’re worried about going low again, use fat and protein after treating with a fast-acting carbohydrate to help sustain your blood sugar. (In many cases, though, this really isn’t necessary. Low blood sugars just require more patience than we’d like to give them!)

I use juice boxes or juice from a bottle at home. Like I mentioned earlier, I keep Gummy Life Savers in my car because they don’t melt or freeze. Juice boxes come with me into the gym, and I keep dried pineapple chunks next to my bed because they are so packed with sugar I only have to eat one or two to bring a low blood sugar back up in the middle of the night. (I have fallen asleep after realizing I’m low due to literally dreading having to consume another juice box and procrastinating the process! The pineapple goes down much easier for me when I’m half-awake.)

I can’t stress enough that using low blood sugars as an excuse to binge on food is always doomed for a disaster (as mentioned earlier in the section about “Getting Off the Blood Sugar Roller Coaster”).

4. Take Really Great Notes!

Pick one form of exercise. Write down the time of day, your pre-exercise blood sugar, anything you just ate, and any insulin you just took. Then write down exactly what kind of exercise you’re doing and for how long you’re doing it. Check your blood sugar halfway through your exercise, and again at the end of your workout. If your blood sugar is high, then you know you either didn’t need to cut back on your insulin dose for the food you ate, or you didn’t need the extra boost of glucose you purposefully consumed for your workout, or you actually need a little bit of insulin in your body during exercise. If you’re low, then you know you can either cut back on your insulin dosing next time (through basal or bolus insulin) or you can consume more carbohydrates uncovered by insulin.

Aim to perform the exact same experiment again, adjusted based on the information you gained from your first experiment, and keep repeating until you find the right balance!

To give you another example, I know that if I’m going to swim for 30 minutes after eating breakfast or lunch, I need 15 to 20 grams of carbohydrates on board, uncovered by insulin, in order to prevent a low blood sugar. To avoid eating unnecessary calories, I time any cardio (glucose-burning) activity for after a normal meal or snack.

Additionally, if you do have a high blood sugar before exercising, don’t be surprised if you need nearly half as much insulin to correct that high blood sugar, but take good notes in this situation and find out! I know for my own body that a 50 percent correction dose of insulin is all I need if I’m high before most types of exercise.

5. Trying Exercising First Thing in the Morning, on an Empty Stomach

This is a secret trick from the bodybuilding world. Bodybuilders are constantly trying to burn as much body fat as possible without burning up muscle. Thanks to being surrounded by bodybuilders when I first became serious about exercise, I learned based on normal human physiology that exercising first thing in the morning, on an empty stomach, with an in-range blood sugar, is the easiest time of day to keep your blood sugar from drop- ping because your body is primed to burn fat for fuel instead of glucose. This is because you have been fasting all night long, your body’s backup stores of glucose have been used for energy while you were sleeping, and so your body uses fat for fuel instead.

For example, if I was going to go for an intense 60-minute walk in the afternoon, it would absolutely lower my blood sugar if I didn’t prepare by consuming extra carbohydrates. However, performing that same 60-minute walk first thing in the morning won’t lower my blood sugar at all. (Obviously, keep glucose on hand when you first perform this experiment, just in case, especially if your background insulin needs are not finely tuned.)

However, I know that for my body, when I perform anaerobic strength- training types of exercise first thing in the morning (or in the afternoon, for that matter), I need one unit of insulin on board to prevent me from spiking. It is just science. That’s all. Take the time to learn and experiment, remembering that an unexpected high or low can simply mean there’s something about exercise and the human body that you haven’t learned quite yet! With attitude, diabetes will never stop you from making exercise a regular part of your life.

Excerpt from Ginger Vieira's latest book, Dealing With Diabetes Burnout. Purchase a copy today!

Ginger is an esteemed faculty member to the DiabetesSisters' Weekend for Women Conference Series and has lived with diabetes for 15 years.