Study Shows Benefits of Exercise on Diabetes are Minimal

An article cited in the medical news recently states "...the prescription of group-based brisk walking represents an equally effective interventional strategy to modulate glycaemic control and cardiovascular risk profile in type 2 diabetes patients compared with a more individualised medical fitness programme."

Sounds good, eh?

But let's look at what they really found.

The study is here: Brisk walking compared with an individualised medical fitness programme for patients with type 2 diabetes: a randomised controlled trial. S. F. E. Praet et. al. Diabetologia, 10.1007/s00125-008-0950-y.

The researchers took 100 people with diabetes and put half of them on a brisk walking regimen that included some resistance exercises. They put the other half on a traditional gym regimen that used machines like elliptical trainers and emphasized weight lifting.

At the end of the year they measured the improvement of the 37 people who stuck with the program.

Thirty seven? Out of one hundred. Hmmm. That's only a tad more than 1/3. In fact, several people recruited dropped out at the very start of the study so only 92 began the exercise programs. So far, this study sounds a lot like real life to me.

But since some did stick with it, let's look at how effective these exercise programs were for blood sugar control.

For all participants, the mean A1c dropped by .14%. That translates out to a lowering of average blood sugar of 4 mg/dl--which is underwhelming when you learn that the beginning average A1c was 7.13% ± 1.36.

The group that did brisk walking dropped their average A1c by .11 and the traditional gym program folks by .18. Hmmm again. That equates to something like 3 mg/dl or 5 mg/dl. It is starting to look like they could have achieved a much better lowering of A1c by dropping 15 grams of carbs from their daily intake.

Their fasting blood sugar declined about 4 mg/dl--in a group that started with a fasting blood sugar that averaged 152 mg/dl.

But surely there must have been other benefits? What about weight? Gyms sell their programs as being a major route to weight loss. Well, that wasn't much better. The people doing the brisk walking lost on average .2% of their BMI. (The researchers did not give the actual amount of weight lost.)

At my BMI, .2% computes to a loss of 1 lb. Over an entire year. The gym group did only slightly better. They lost an average of .8% of their BMI. That is about 4 lbs.

The rest of the parameters they measured weren't much better. Systolic blood pressure decreased about 10 mmhg. Diastolic (the bottom number) by about 5 mmhg. Cholesterol decreased by a similar trivial amount.

I'm scratching my head. Did the researchers really call this an "effective interventional strategy to modulate glycaemic control and cardiovascular risk profile in type 2 diabetes patients?"

Would any sane person put themselves through all the effort of doing all that exercise if they knew in advance that their results would be so unimpressive?

I like walking. It does good things for my leg muscles and makes me feel healthier, but having read this study I feel a lot better about my own results which, over the years, have been no weight loss, and no change in blood pressure or blood sugar no matter how long or regularly I walked.

I thought I was some kind of oddball, but these results suggest I am in fact typical.

But you do have to wonder who comes up with these definitions of "effective!"