Guest Post By: Samantha Tarantino
Energy for exercise is provided by glucose and fatty acids (aka fat). Glucose enters your muscles (thanks to insulin!) and your muscles have the energy to kick your workout’s butt.
What your body is doing:
During the first 15 minutes of exercise, glucose is used from blood stream and muscle glycogen. After 15 minutes, glycogen from the liver is converted to glucose to be used for energy. After 30 minutes, fat is also used as an energy source.
So, if the process is similar, why do different types of workouts impact blood sugars differently?
Well, it depends on the intensity.
Higher intensity workouts stimulate glycogen in the liver to release a surge of endogenous glucose.
-Utilization of glucose cannot keep up with the production of glucose.
-Furthermore, without enough insulin in your system, the glucose will not be able to be converted to energy for your muscles.
This leads to excess sugar in your bloodstream…aka a hyperglycemic episode!
Glucose production >> glucose utilization
Lower intensity workouts can lead to hypoglycemia.
-There is endogenous glucose production increase, however, utilization of glucose works a lot faster than its production.
-Glucose levels, even endogenous ones (from your liver!) are attenuated more quickly.
Glucose production << glucose utilization.
But wait! What is considered intense?
Intensity depends on timing, format, and max heartrate (HR).
If you’re above 80% of your max HR, then you enter an anaerobic state. Anaerobic exercise does not use oxygen for energy. Glucose is released at a faster pace than the body can use it.
Aerobic exercise, where oxygen is used for energy, has a HR less than 80%. Since it is less intense, a surge of glucose does not outweigh use of glucose. Having oxygen as a primary energy source also helps lower that glucose surge!
How do I calculate my max heartrate?
Calculating your max heart rate:
220- Your age= Maximum heart rate
For example, I am 24 so my max HR is 196! Then I based my intensity percentages on that. If I work at 85% effort of my max HR, then my HR will be at 166. The chart below gives quick indications!
Breaking Down Types of Workouts:
HIIT, Tabata, CrossFit: Hyperglycemic Risk;
Steady state cardio: Hypoglycemic risk:
Strength training: Most likely Hyperglycemic Risk
Although an anaerobic exercise, it depends on what type of movements you are doing.
Compound exercises (like squatting, deadlifts, bench press) require more energy and increase your HR. You’ll be at risk for hyperglycemia.
However, doing just less intense exercises like triceps extensions (or any accessory muscles) you won’t likely see a spike in blood sugar.
BUT, you typically use compound movements in your strength training routine along with accessory exercises. Therefore, you’re more like to have a hyperglycemic episode.
What can I do to combat my crazy blood sugars?
About the Writer:
Samantha Tarantino is a certified personal trainer and diabetic health coach. She has battled type one for over 19 years. She received her BS in Neuroscience and is now continuing her education with a PhD in Bioengineering. She is nominated for Type One Diabetic Fitness Influencer of the Year by Myabetic.
For individuals with Type 1 Diabetes on insulin, low blood sugar due to exercise is highly likely if the appropriate preventative measures are not taken. However, diabetes and the fear of exercise induced hypoglycemia should never deter someone from engaging in any type of physical activity. In this blog post we will discuss 4 tips on how to prevent low blood sugar while exercising.