A new Canadian study found that compared to no exercise, either aerobic exercise or resistance training helped people with type 2 diabetes control blood sugar, and doing both was even more effective.

The findings of the randomized, 26-week controlled trial, which was carried out in 8 community based centres all over Canada, are published in the September 18th, 2007 issue of the Annals of Internal Medicine.

The study was conducted by lead author Dr Ronald Sigal, associate professor of medicine and cardiac sciences at University of Calgary, Alberta, Canada, and colleagues.

Sigal said scientists already knew something about the benefit of exercise on blood sugar levels:

"We know that aerobic exercise improves glycemic control."

But what was less clear, said Sigal, was the effect of other types of exercise, particular resistance exercise, involving the lifting of weights to build strength:

" Some thought that resistance exercise is not useful or even dangerous for some people with diabetes," he explained.

Sigal and colleagues enrolled 251 sedentary adults with type 2 diabetes, aged 39 to 70 who were not taking regular exercise. They had to pass a stress test or be cleared for exercise training by a cardiologist though, and show they could stick to a 4 week exercise programme before being enrolled in the trial.

The participants were randomly assigned to one of four groups:

One group did 45 minutes of aerobic training, on treadmills and exercise bikes, three times a week (aerobics group).

A second group did 45 minutes of resistance training, on weights, three times a week (resistance group).

A third group did 45 minutes of aerobics and 45 minutes of resistance training three times a week (combined aerobics and resistance group).

A fourth group did no exercise (control group).

The researchers…