# Exercise as it relates to Disease/Aerobic and resistance exercise on glycemic control in adults with type 1 diabetes

This is a critique of the article "Effect of Aerobic and Resistance Exercise on Glycemic Control in Adults with Type 1 Diabetes" by Reddy R, Wittenberg A, Castle J, Youssef J, Winters-Stone K, Gillingham M, Jacobs P. (2019)
This is created as an assignment for the unit Health, Disease and Exercise at the University of Canberra.

# What is the background to this research?

Type 1 diabetes (T1D) is an autoimmune condition where the immune system destroys the cells in the pancreas which produce insulin. Without the insulin the body will not be able to turn glucose into energy which in turn will cause the body to produce fat substitutes which chemical substrates into the blood stream which can be deadly if untreated. T1D is a disease that represent around 10% of all diabetes, and many people first diagnosed have trouble controlling their glucose levels, with this research it fills a gap around the existing physical activity guidelines with proper research and results. It is important for people with diabetes to understand their glucose levels and what it means to their body, as each person has a range of low and high blood glucose levels which are different in each person.
The purpose of this study was to assess whether aerobic and resistance exercise has an impact in the control of glycemic levels in adults with type one diabetes over a three-week period.

# Where is the research from?

The research was conducted in the United States of America, by the following authors and their institutions. OHSU - Oregon Health and Science University
* Ravi Reddy, Peter G Jacobs and Joseph EI Youssef - Department of Biomedical Engineering, OHSU, Portland, OR
* Amanda Wittenberg and Melanie Gillingham - Department of Molecular and Medical Genetics, OHSU, Portland, OR
* Jessica R Castle and Joseph EI Youssef - Department of Medicine, Division of Endocrinology, Harold Schnitzer Diabetes Health Center, OHSU, Portland OR
* Kerri Winters-Stone - School of Nursing, Human Performance Laboratory, OHSU, Portland, OR

# What kind of research was this?

This research of a pilot study used a three-week randomised crossover trial of 10 physically fit adults (6 Females and 4 Males) with T1D ranging from the ages of 33-39.
In a randomised crossover trial, all participants will be exposed to the same exercise interventions throughout the length of the study. This allows the researchers to compare the results of the participants treatment A, and the same participants treatments B and C or vice versa. In the analysis of a crossover trial, it can be evident that a 'carry over' between the treatments may be present, which leads to not being able to rule out a type II error. This means that the results of these trials may not be as accurate compared to a randomised control trial.

# What did the research involve?

Before the intervention took place each participant was sent to complete visits consisting of a VO$_{2max}$ test, a dual X-ray absorptiometry scan, as well as a one week run in period. Safety precautions were set so the continuous glucose monitor would send an alert if their glucose levels pass 3.1 mmol/L and 16.67 mmol/L.
10 physically fit adults were assigned to two in-clinic exercise session lasting 45 minutes for 3 weeks of intervention involving: 1 week of aerobic exercise (AE), 1 week of resistance training (RT), and 1 week of no exercise (the control). The order in which these were completed was randomised between each participant. In the RT session, each participant completed a brief warmup, and three sets of 8–12 repetitions at 60-80% of 1-RM of different upper and lower body exercises (leg press, bench press, leg extension, leg flexion and seated row). With the AE the participants completed a treadmill based exercise with the results of the VO$_{2max}$ test the speed and grade of the treadmill was adjusted to keep the participants at a work-rate of 60% VO$_{2max}$.
A limitation of this study includes the small sample size as only 10 people participated in this study this may not be seen as enough data to be seen as reliable.

# What were the basic results?

The results were described in two sections based on the method, first the in-clinic training results on their glycaemic control and second a 24 hour period after the exercise was completed.
Within the in-clinic exercise sessions differences were found with the participants glycemic levels. Aerobic exercise caused a dangerous reduction on glucose levels with a reduction of 3.94 ± 2.67 mmol/L, while the reduction of glucose was smaller in the resistance exercise intervention with a mean reduction of 1.33 ± 1.78 mmol/L.
An adjusted table of results for the 24-hour post exercise glucose levels can be seen below:
24hr post-exercise glucose levels :
| | Control | AE | RT |
| Time in range (%) | 55.7 ± 25 | 60.5 ± 22 | 70.3 ± 15 |
| Glucose mean (mmol/L) | 9.5 ± 2.7 | 8.80 ± 2.17 | 8.01 ± 1.94 |
| 24 hr. insulin dosage (U) | 43.6 ± 9 | 40.8 ± 9 | 39.8 ± 9 |
Based on the table the mean percentage range for the 24 hours post exercise was significantly greater in the resistance exercise during the control period (70.3% vs. 55.7%, p=0.013) but no so much in post aerobic exercise (60.5% vs. 55.7%).

# What conclusions can we take from this research?

Resistance exercise is shown to have a positive effect on the glycemic control in adults with T1D. As this is the case, The resistance training may result in differences in the mean glucose and the time in range if time was extended past a 24-hour cut off, or different training hours were done. Both types of exercise are recommended for people with T1D, but the positive effect of the aerobic exercise could be due to the food intake in pre and post exercise meals.
This study aligned with another study in 2011 where a similar exercise intervention was taken and showed similar results concluding that exercise does help with the glycemic control in adults with type 1 diabetes.

# Practical Advice

Within the aspects of ability to exercise each participant/patient should complete an Adult Pre exercise Screening System (APSS) tool prior to starting the exercise. The ESSA screening tool lets the exercise conductors know whether one has any underling health issue that need to be cleared before exercise. As these participants all have T1D, they would need to seek approval from a GP to start the exercise if this were to be used.
As walking, dancing, swimming, doing sit ups and squats are all recommended forms of physical activity for people suffering from diabetes, It is always a good idea to tell someone when you are exercising just in case of a medical episode during your exercise. Checking on heart rate and blood sugar levels during exercise is recommended and keeping some necessary sugars and hard carbohydrates close by to prevent a diabetic episode and over exertion.

# Further information/resources

Further information relating to diabetes can be found in the following links:
* Diabetes Australia: https://www.diabetesaustralia.com.au/about-diabetes/type-1-diabetes/
* World Health Organisation: https://www.who.int/news-room/fact-sheets/detail/diabetes
* Diabetes fact sheets: https://diabetesnsw.com.au/diabetes-information-sheets/
Anyone suffering from diabetes, their family members or careers need support the NDSS helpline can be found here or by calling the helpline on 1800 637 700.

# References

* 1 2 3 4 5 6 7 8 9 10 11 12 Reddy, R., Wittenberg, A., Castle, J. R., El Youssef, J., Winters-Stone, K., Gillingham, M., & Jacobs, P. G. (2019). Effect of Aerobic and Resistance Exercise on Glycemic Control in Adults With Type 1 Diabetes. Canadian journal of diabetes, 43(6), 406–414.e1. https://doi.org/10.1016/j.jcjd.2018.08.193
* 1 2 3 unknown.(2021).Type 1 diabetes. Diabetes Australia. https://www.diabetesaustralia.com.au/about-diabetes/type-1-diabetes/
* 1 2 Sibbald, B., & Roberts, C. (1998). Understanding controlled trials. Crossover trials. BMJ (Clinical research ed.), 316(7146), 1719. https://doi.org/10.1136/bmj.316.7146.1719
* ↑ Iscoe, K. E., & Riddell, M. C. (2011). Continuous moderate-intensity exercise with or without intermittent high-intensity work: effects on acute and late glycaemia in athletes with Type 1 diabetes mellitus. Diabetic medicine : a journal of the British Diabetic Association, 28(7), 824–832. https://doi.org/10.1111/j.1464-5491.2011.03274.x
* ↑ ESSA. Pre-Exercise Screening Systems. (2019). Available at: https://www.essa.org.au/Public/ABOUT_ESSA/Pre-Exercise_Screening_Systems.aspx
* ↑ NDSS. physical activity fact-sheet. (2020). Available at: https://www.ndss.com.au/about-diabetes/resources/find-a-resource/physical-activity-fact-sheet/