Exercise as it relates to Disease/Controlling Type 2 Diabetes with High Intensity Interval Training

This is an analysis of the journal article "High Intensity Interval Training Improves Glycaemic Control and Pancreatic β Cell Function of Type 2 Diabetes" By Madsen et al.

What is the Background to this Research
Diabetes is recognised as the world’s fastest growing chronic condition with one in every eleven adults suffering from diabetes. According to the International Diabetes Federation the estimated worldwide prevalence of diabetes was 382 million in 2013 with a projection of 592 million people suffering from type 2 diabetes in 2030. Type 2 diabetes (T2D) is accounted for around 85% of diabetes cases.

Someone who is suffering from T2D will have high levels of blood glucose as a result of insulin deficiency. The most common factor to insulin resistance is central obesity. The ADA describe T2D as the most common form of diabetes, occurring with increasing frequency with age, usually associated with insulin resistance and always with either relative or absolute insulin deficiency and not generally requiring insulin treatment for survival. In 2013 it was recommended that T2D sufferers should partake in at least 150 minutes per week of moderate-intensity aerobic exercise corresponding to 50-70% of maximal heart rate.

Exercise is considered the cornerstone of diabetes management, along with diet and medication, with this in mind this study looks at the regulation of glucose, effects on pancreatic β cell function, and total fat mass before and after 8 weeks of low volume high intensity training on a cycle ergometer in T2D patients and healthy individuals.

Where is the research from
Madsen, Thorup, Overgaard & Jeppesen from Aarhus University, Denmark gathered their subjects from advertisements in the local newspapers of Aalborg and also evening sessions at the Centre for Clinical research, Vendsyssel Hospital, Aalborg University where the study was carried out.

What kind of research was this
This is a randomised control trial that is looking at the effects of 8 weeks of HIIT training between people with T2D and people without. There are other studies referred to throughout the article that present similar positive results.

What did the research involve
10 T2D patients and 13 control patients were eligible for the study, with the T2D group aged around 56 +/- 2 years and control 52 +/- 2 years. As part of the selection criteria participants were required to have sedentary lifestyles and this was gaged through initial medical screening which was conducted at the very beginning of the study to gage their individual lifestyles. There were exclusion criteria such as:


 * Diabetes for less than one year
 * BMI less than 25 kg/m-2
 * Moderate intensity exercise more than 1 hour per week
 * Use of exogenous insulin
 * Any evidence of other cardiac, metabolic, neuromuscular or physiological diseases that would contraindicate partaking in physical activity.

Before study started and after the 8 weeks were completed participants underwent:


 * Two hour oral glucose tolerance test (OGTT)
 * Resting blood pressure
 * Incremental maximal oxygen uptake (VO2max) cycle ergometer test
 * Whole body dual X-ray absorptiometry (DXA)

Participants than exercised 3 times a week (10x60 second HIIT) over an 8-week period on a cycle ergometer, all exercise was supervised. Once the 8 weeks was completed the same tests listed above were redone to attain end results. These results were then statically analysed by applying the STATA 13 statistical analysis system.

What were the basic results
Note: All results were based on initial screening completed directly before the start of the study.

What conclusions can we take from this research
After the 8 weeks of low volume HIIT, we saw the participants with T2D improve their glycaemic control. It is stated here that HIIT is more effective at improving glycaemic control than regular moderate intensity exercise. These findings are in line with other studies that have been performed on the benefits of exercise and T2D. One paper stated that two randomised trials were completed that involved lifestyle interventions involving ~150 min/week of physical activity and diet-induced weight loss of 5-7% reduced the risk of progression from impaired glucose tolerance (IGT) to T2D by 58%. These 8 weeks of HIIT training were also beneficial to lowering participant’s blood pressure and abdominal fat in both the T2D group and the control group. After 8 weeks of adhering to 3 days of activity, a habit was formed and formerly inactive people will now be adding in this activity to their daily routine and is something that they find manageable.

Practical advice
This study has shown that HIIT three times a week has positive effects in T2D patients while also being an easy enough activity to continue on with in the future. Following this exact program may require for individuals to seek out a stationary bike for the home or to sign up at a gym, therefore making it slightly harder to continue on with this set program. However, there are other alternatives to HIIT training that could be easier for the wider population. Advice should be sought from a medical practitioner before undergoing any sort of exercise regime.

Further Information/Resources

 * Diabetes Australia: https://www.diabetesaustralia.com.au/
 * Exercise and Type 2 Diabetes: http://care.diabetesjournals.org/content/diacare/29/6/1433.full.pdf
 * The prevention of Type 2 Diabetes through Lifestyle Changes: http://www.nejm.org/doi/pdf/10.1056/NEJM200105033441801
 * Management of Type 2 Diabetes: http://www.ncbi.nlm.nih.gov/books/NBK53885/pdf/Bookshelf_NBK53885.pdf
 * Reducing Type 2 Diabetes through Lifestyle interventions or Metformin: http://www.nejm.org/doi/pdf/10.1056/NEJMoa012512