Science Based Wellness

In a previous posting, What is Evidence, I examined the link between the onset of type 2 diabetes and obesity. I expressed doubt that it was possible to reduce significantly the risk of type 2 diabetes through weight loss alone. Here, as I explained, I was going against the accepted medical wisdom.

About Diabetes

The website of the American Diabetes Association (ADA) defines diabetes as “…a disease in which the body does not produce or properly use insulin.”

Insulin is defined as “…a hormone that is needed to convert sugar, starches and other food into energy needed for daily life.”

The website goes on to distinguish between type 1 and type 2 diabetes. In type 1 diabetes the body fails to produce insulin at all. This is a congenital condition and probably has nothing to do with lifestyle.

In type 2 diabetes the body becomes resistant to the effects of insulin.

It works like this. In a healthy body insulin stimulates the transport of glucose from the blood into cells where it is used to produce energy. In individuals with type 2 diabetes this either does not happen at all or does not happen with sufficient speed. As a result blood glucose levels rise. This can cause damage to various organs of the body – especially the cardiovascular system. If left untreated it results in death.

Most people diagnosed with diabetes have type 2 diabetes which used to be called adult-onset diabetes. Lifestyle factors could play a role in the onset of type 2 diabetes.

The ADA website also discusses pre-diabetes, a condition that usually precedes the onset of type 2 diabetes. Pre-diabetics have elevated blood glucose levels due to insulin resistance. There is some evidence that damage is to the heart and cardio-vascular system occurs during pre-diabetes.

What Causes Type 2 Diabetes?

Let’s be clear. No one can say for certain what causes an individual to get type 2 diabetes. In some cases a genetic pre-disposition towards diabetes may be a contributing factor. In other cases it may be exposure to pollutants.

However there seems to be little doubt that lifestyle factors do play a role. The incidence of type 2 diabetes has been rising – especially among younger adults and children. One factor in the rise of type 2 diabetes seems to be obesity and fatties do seem to be at increased risk of getting the disease.

The Role of Exercise

Another factor seems to be simple lack of exercise. It is on exercise that I want to focus. The evidence that exercise can delay and may even prevent the onset of type 2 diabetes is overwhelming.

I could cite many scientific papers and articles but I’ll focus on two. The first, by Frank W. Booth and P. Darrel Neufer appeared in American Scientist Vol 93. It is called “Exercise Control Gene Expression.” One of the topics covered is exercise, fitness and blood sugar levels. One of the authors, Neufer, found that a single bout of aerobic exercise improves the body’s response to insulin and limits the rise in blood glucose levels after meals.

That’s right! Just one bout of exercise enhances your body’s response to insulin. In scientific terms, exercise boots your “insulin sensitivty.”

The downside is that the benefit dissipates quickly if you do not exercise. After a few day of inactivity the benefit disappears.

Scientists are slowly closing in on the mechanism through which exercise improves the body’s response to insulin. In a paper to appear in an upcoming edition of the journal, Diabetes, Gregory Cartee and Katsuhiko Funai of the University of Michigan discovered that a protein called TBC1D1 plays an important role in stimulating exercise induced insulin transport from the blood into cells. You can read a summary of their findings on the University of Michigan website.

I could cite many more papers and articles but this will do. There is clear evidence that exercise has a beneficial effect on blood glucose levels. The papers I’ve cited are not mere epidemiological studies that find an association between exercise and enhanced insulin sensitivity; both papers trace the molecular pathways through which exercise boosts he body’s response to insulin.

Evidence ratings:

Maintaining a healthy weight will on its own significantly delay or prevent the onset of type 2 diabetes or pre-diabetes:		5 out of 10
..
Maintaining a healthy weight plus regular exercise will significantly delay or prevent the onset of type 2 diabetes or pre-diabetes:		8 out of 10

What constitutes regular exercise? I shall have a lot to say about this later. However a good rule of thumb is at least half and hour of reasonably strenuous exercise daily.

What constitutes strenuous exercise? Another rule of thumb states that during your exercise bout you should be able to talk but not sing. This does not work for me since I am unable to sing at any time. At least so my friends tell me.

Is Exercise the Key to a Healthy Lifestyle?

As I shall argue here, exercise is the under-appreciated wonder drug. Avoidance of type 2 diabetes may be among the least of the benefits affored by regular exercise.

Tags: diabetes, exercise, insulin resistance

This entry was posted on Thursday, April 16th, 2009 at 11:55 pm and is filed under diabetes, exercise, obesity. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.