Monday, January 16, 2012

Janathon 212 Day 15: Some progress

Janathon 212 Day 15: Run 3.17 miles, Time - slowish, Weather - crisp and cold, bright and blue

A glimmer of hope today: I managed to run most of the way without walking to reduce my heart rate. It was not fast but at least it was a sign that the current discipline might become  becoming manageable; a sign that things are not hopelessly stuck. Huzzah!

Everything I have read about base training emphasises that it is a matter of patience - and so patient is what I will be. I am now looking forward to my next run to see if the progress will be maintained.

But enough of me. I need to return to the subject of exercise and health and the evidence of benefit

The obvious place to start is Cochrane Reviews, which are systematic reviews of the primary literature in health care and health policy. They have done a number of reviews about the effects of exercise. The first I looked at concerned its effect on type 2 diabetes.

The findings were:

Fourteen randomised controlled trials comparing exercise against no exercise in type 2 diabetes were identified involving 377 participants. Trials ranged from eight weeks to twelve months duration. Compared with the control, the exercise intervention significantly improved glycaemic control as indicated by a decrease in glycated haemoglobin levels of 0.6% (-0.6 % HbA1c, 95% confidence interval (CI) -0.9 to -0.3; P < 0.05). This result is both statistically and clinically significant. There was no significant difference between groups in whole body mass, probably due to an increase in fat free mass (muscle) with exercise, as reported in one trial (6.3 kg, 95% CI 0.0 to 12.6). There was a reduction in visceral adipose tissue with exercise (-45.5 cm2, 95% CI -63.8 to -27.3), and subcutaneous adipose tissue also decreased. No study reported adverse effects in the exercise group or diabetic complications. The exercise intervention significantly increased insulin response (131 AUC, 95% CI 20 to 242) (one trial), and decreased plasma triglycerides (-0.25 mmol/L, 95% CI -0.48 to -0.02). No significant difference was found between groups in quality of life (one trial), plasma cholesterol or blood pressure.

So it had a good effect but not as overwhelming as promised in the video especially as it did not seem to improve quality of life.


Travelling Hopefully said...

Oh, this is good for getting my head in critical analysis mode (note to self, start writing essay). My first thought was "what do they mean by exercise?" followed by "how did they measure quality of life?".

Turns out quality of life was only measured in one of the studies and that was a trial involving elderly patients. I'm not saying that the elderly are miserable, but there's often other factors that influence quality of life. I shall now fight the urge to look at primary data...

Highway Kind said...

What is exercise? What is quality of life? When terms can be so elastic it Shows the difficulty of finding good answers.

As for confounding factors with the elderly: there are probably as many such factors with other age groups - they are just different.

My comment about quality of life at the end was just a throw away. I think we are going to find the significant answers in mortality figures and disease prevention