Exercise as it relates to Disease/The ant-inflammatory effects of exercise in type 2 diabetes

Nicholas Tankey

Health, Disease and Exercise

Prevelance
The prevalence of obesity continues to rise across the world and is accompanied by a direct proportional increase in other medical conditions such as type 2 diabetes mellitus. Within Australia, approximately 846,000 individuals have been diagnosed with type 2 diabetes according to the 2011-2013 National Health survey.

Impact of type 2 diabetes on health
Patients suffering from type 2 diabetes are at increased risk of developing a number of serious medical conditions including cardiovascular disease. Research has shown that people suffering from type 2 diabetes are 2-4 times more likely to suffer from cardiovascular disease than healthy individuals. Inflammation has been shown to be linked between both diabetes and cardiovascular disease.

Affect of Exercise on type 2 diabetes
The objective of treatment for patients with type 2 diabetes is to reach and maintain healthy blood glucose, lipid, and blood pressure levels to prevent or hinder the chronic effects of the disease. Many people suffering from type 2 diabetes achieve this through participation in exercise. Exercise is an essential treatment mechanism because it helps treat blood glucose, blood lipid and blood pressure abnormalities as well as aids in weight and fat loss/maintenance. Besides helping manage these factors, exercise has also been suggested to help reduce the chronic inflammatory state in which patients suffering from diabetes find themselves in.

Where is the research from
This particular study is from the European Journal of Cardiovascular Prevention and Rehabilitation, now known as the european Journal of Preventive Cardiology. It is currently the leading journal for preventative cardiology practices and plays a role in reducing the impact of cardiovascular disease. The study was conducted at the AHEPA University Hospital in Athens, Greece.

What kind of research was this
This specific study was both randomised and controlled. This allowed the performers to implement a process and study its outcome on intervention groups compared to that of the control group. This type of study helps eliminate bias and allows for good evidence showing the cause and affect of a particular treatment.

What did the research involve
The research was conducted using 60 diabetic patients with a mean age of 62 years. The individuals were recruited from a diabetic clinic and were randomly assigned to either exercise or control group. The research was conducted using 60 diabetic patients with a mean age of 61.64 years. The individuals were recruited from a diabetic clinic and were randomly assigned to either exercise or control group. The control group conducted no extra activity and went about their daily lives as usual. The exercise group however performed a six-month training program consisting of four trainings per week for a length of roughly 45–60 minutes per session. Each session con sited of a 10 minute warm-up, 30–45 minutes of aerobic exercise in the form of walking, running, cycling or calisthenics and a 5 minutes cool down. The intensity of the exercise was originally quite low, but as the patients progressed through the program, the intensity was gradually increased.

Analysis of a number of variables were measured for each individual at both the beginning and end of the study. The variables measured were body dimensions including body weight, BMI and waist-to-hip ratio, cardiorespiratory fitness, glycemic and lipid levels, c-reactive protein, adiopectin, interleukin (IL-10 and IL-18), tumour necrosis factor, insulin levels, body fat, and blood pressure.

What was the aim of the research
The aim of the research was simple, to see if an aerobic exercise program would improve the inflammatory state of the patients by changing the concentrations of the inflammatory and anti-inflammatory markers within their bodies.

What were the basic results
As the researchers expected, there were a number of statistically significant changes between the exercise group and the control group. Interestingly, there were no significant changes in body dimensions between the exercise and the control group. In response to the exercise program, the exercise group drastically reduced there systolic blood pressure whilst also lowering there diastolic blood pressure and fat mass. In regards to insulin and lipid profiles, glycated haemoglobin, fasting plasma glucose, insulin resistance index, fasting insulin levels and lipid levels all improved. Not surprisingly, the results showed that the exercise group increased their fitness levels, allowing them to perform endurance exercises for longer and at a higher intensity (VO2 max). In terms of cardiovascular risk factors, the exercise group showed significant reductions in both C-reactive protein and IL-18 concentrations, inflammatory markers, known to increase the risk of a cardiovascular event.. Another change observed during the experiment was the increase in IL-10 concentrations of the exercise group, an anti-inflammatory marker, known to reduce the risk of cardiovascular disease.. Unexpectedly there was no change in TNF-alpha levels in either of the groups.

How did the researchers interpret the results
The researchers performed thorough analysis on the results and presented several key findings in which they thought were significant. Firstly the reduction of IL-18 within the exercise group was seen as a positive affect. IL-18 is a member of the IL-1 family and represents a strong predictor of cardiovascular morbidity and mortality. A drop in IL-18 levels indicates a reduction of the inflammatory state seen within the diseased patients, whilst also lowering the chances of a cardiovascular related incident. The researchers explain there are two mechanisms in which the lowering of IL-18 may occur. The first mechanism in which the IL-18 may be lowered is through changes in the insulin signalling pathway. The second mechanism mentioned by the researchers suggested that exercise suppresses cytokine function, reducing infiltration of adipose tissue inflammatory cells. The researchers also explained that the decrease in IL-18 could have positively impacted on the increase seen in the Vo2 max of the patients.

Secondly, the rise in IL-10 within the exercise group was also seen as a positive. IL-10 has been shown to reduce the risk of future cardiac events, so a rise in the serum of levels of this particular anti-inflammatory cytokine can only be seen as good. The rise in IL-10 after exercise was credited to individuals change in fitness status and a reduction in body fat. The increase in IL_10 was suggested to have improved the patients Vo2 max.

The balance between pro inflammatory and anti-inflammaorty cytokines such as IL-10 and IL-18 has recently been suggested to be a predictive measure of acute coronary conditions and their clinical outcomes. This research shows how exercise can shift the ratio towards the anti-inflammatory function. In doing this, it can be said that exercise provides protection against inflammation and atherosclerosis.

In regards to the decrease in C-Reactive protein, the reduction in blood levels was said to be a promising finding.

Conclusions
From the research, it can be said that a long term aerobic exercise program was effective at reducing the inflammatory state of diabetic patients, stimulating anti-inflammatory mechanisms within the body. Furthermore, this researches shows how a aerobic training program can improve biochemical variables within the body, deceasing the likelihood of suffering from other diseases, in particular, cardiovascular disease.

Implications of this research
This research opens the door for other studies to investigate the benefits of exercise on diabetic patients. The results have shown that exercise can reduce the inflammatory state of individuals suffering from diabetes, but shows no insight as to whether or not exercise can be used to prevent diabetes from developing. Also, different training methods such as resistance training should also be look at to see if they to reduce the inflammatory state amongst diabetic individuals. This is important, particularly for those who can not perform long duration aerobic exercise such as the morbidly obese.

Primary research article
Kadoglou, Nikolaos, Iliadis, Fotios, Perrea, Despina, Liapis, Ch et al. 2007, The anti-inflammatory effects of exercise training in patients with type 2 diabetes mellitus, European Journal of Cardiovascular Prevention and Rehabilitation, 14: 837-843