by Trisha Thacker
According to the American Diabetes Association’s 2019 Guidelines, most adults with Type 1 and Type 2 diabetes should engage in at least 150 minutes of moderate to vigorous intensity aerobic exercise per week. Dr. Michael Riddell acknowledges that regular exercise is critical for living longer and healthier lives with fewer consequences from diabetes. However, he is aware that regular exercise does not come without challenges, particularly those around glycemic control.
On May 13, 2020, Dr. Michael Riddell was featured by the Advisor Academy and spoke on the subject of ‘technologies supporting exercise adherence and control in diabetes’. Dr. Riddell is a researcher living with Type 1 Diabetes. He has published over 150 original research articles and 18 book chapters and is currently a professor and the graduate program director at York University’s School of Kinesiology and Health Science. Written below in a Q&A format, are some of the key takeaways from Dr. Riddell’s talk. To learn more, click on this link to view the Dr. Riddell’s full talk.
1. Why does physical activity induce hypoglycemia in people living with diabetes?
Dr. Lawrence was the first to explore the effect of exercise on insulin action in diabetes, through a study he conducted in 1926. He observed his own blood sugar levels after injecting insulin and remaining sedentary on one occasion and exercising on another. He noticed that exercise can act like insulin in lowering glucose because it increases the glucose uptake in working muscles and boosts metabolism. The glucose uptake by the muscles exceeds the glucose production by the liver and this causes glucose levels to drop. However, these properties also mean that physical activity can reduce blood sugar to the point of hypoglycemia, which can be dangerous.
2. What are the effects of different types of exercise on blood glucose levels?
Different forms of physical activity have different effects on glycemia:
- Aerobic exercises such as walking, jogging, swimming and cycling cause glucose levels to drop. However, there is individual variability which is not fully understood but could be related to factors such as fitness level, muscle mass etc.
- Anaerobic exercises that are more intense in nature such as mixed martial arts and power lifting tend to push glucose levels up, again to variable individual levels.
- Exercises that involve a combination of aerobic and anaerobic effort, such as tai chi, yoga and gymnastics – have a moderating effect and typically keep glucose levels flat. They involve intervals of modernity aerobic activity and high bursts of anaerobic activity and can be achieved through high intensity interval training (HIIT) workouts.
3. What are the current devices and emerging technologies working towards preventing hypoglycemia during exercise?
Some of the current technologies to prevent hypoglycemia during exercise include hybrid-closed loop systems. For example, the Tandem Basal IQ Technology has a forecast for hypoglycemia that can be used during physical activity to turn off basal rates.
In terms of emerging technology, there is ongoing research looking at the efficacy of a mini dose of glucagon prior to exercise. There is also work on the dual hormone artificial pancreas system that can inject both insulin and glucagon. However, both of these are still at the investigational stage and have not yet been approved for use.
4. What are some recommended technologies that facilitate exercise adherence for those living with diabetes?
Peloton is a good but non-diabetes specific app – it started as a stationary bike workout program, but now provides coaching for running, cycling and bootcamp workouts. Zwift is a competitive running and cycling app. There are many different communities within the app including a large cohort of T1 riders called ‘Team Type 1’.
GlucoseZone is the best evidence-based app for prescribing workouts to people living with type 1, type 2 and pre-diabetes. It educates users on different types of exercises and their effect on blood glucose. It also allows users with T1D to enter their insulin therapy routine and connect CGM data. It can customize workouts based on the blood glucose levels right before exercise.
5. What is the best time during the day perform light aerobic exercise?
The time of day that is most safe for light aerobic exercise is right after a meal. A study conducted by Manohar et al in 2012, showed that patients with T1D and T2D diabetes had less glucose excursion and no bouts of hyper or hypoglycemia when they exercised for 20 minutes right after their largest meal of the day.
However, carbohydrate dosing must be adjusted accordingly – this is influenced by the duration of exercise. According to a Lancet Diabetes 2017 statement, no carbohydrate intake is typically needed if the exercise right after the meal is mild and shorter than 30 minutes. If the exercise is 30-45 minutes long, 10-20 gm of carbohydrate intake may be needed depending on the change in glucose levels. If the exercise is more intense and longer than one hour, 0.5-1.0g/kg/hr of carbohydrate intake is typically needed for glycemia and performance.
These questions provide a glimpse of some of the important issues explored by Dr. Michael. He also touched upon insulin-management strategies to prevent hypoglycemia during and after exercise and tips to assess rise of blood glucose during exercise. To get in-depth insights into exercising with T1D and T2D diabetes, watch his full talk!
Disclaimer: All the information in this post is paraphrased directly from Dr. Michael Riddell’s AdvisorPro talk. Please view the full lecture and consult with your physician prior to adopting any of these strategies.
- American Diabetes Association. “5. Lifestyle Management: Standards of Medical Care in Diabetes-2019,” January 1, 2019. https://care.diabetesjournals.org/content/42/Supplement_1/S46.
- “Dr. Michael C. Riddell.” Michael Riddell, September 3, 2019. https://mriddell.lab.yorku.ca/biography/.
- Manohar, Chinmay, James A Levine, Debashis K Nandy, Ahmed Saad, Chiara Dalla Man, Shelly K McCrady-Spitzer, Rita Basu, et al. “The Effect of Walking on Postprandial Glycemic Excursion in Patients with Type 1 Diabetes and Healthy People.” Diabetes care. American Diabetes Association, December 2012. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3507567/.
- Riddell, Michael C, Ian W Gallen, Carmel E Smart, Craig E Taplin, Peter Adolfsson, Alistair N Lumb, Aaron Kowalski, et al. 2017. “Exercise Management in Type 1 Diabetes: A Consensus Statement.” The Lancet Diabetes & Endocrinology 5 (5): 377–90. https://doi.org/10.1016/s2213-8587(17)30014-1.