EXERCISE AND DIABETES

Type 2 versus Type 1 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is what we are talking about. Type 1 DM is something else although it is also a risk factor for cardiovascular disease. T1DM is a condition whose onset is usually in young people whose pancreas fairly suddenly packs in and stops producing insulin. Type 1 diabetics can only survive by regularly injecting themselves with insulin for the rest of their days.

T2DM develops later in life and is largely a result of an unhealthy lifestyle. There is a genetic element. The tendency to develop T2DM is inherited but it rarely manifests in the absence of over-eating and under-exercising. This form of diabetes is a growing epidemic with progressive increases in rates of diagnosis as the population becomes older and fatter – and less active. In the mid-nineteen nineties about two to three per cent of the UK population were known to be affected. The figure now is about 6% and growing. There are about four million diabetic patients in the UK, with more than 21,000 deaths per annum. The cost to the NHS of managing diabetes is a staggering £11.7 billion which is more than 12% of the total NHS budget!

Prevention is the key to reducing this epidemic – so it is extremely helpful to know the exercise and fitness levels of diabetics. This has now been examined in a group of 150 individuals with T2DM attending a single medical centre. All underwent a maximal treadmill exercise test¹. The mean age was 54.9 and BMI (body mass index – see glossary) was 34.5 – well into the obese category. Average reported daily activity was expressed as kcal/kg and came to 34.3 kcal/kg which is only 7% above the sedentary state.

Fitness levels

These were very low – as measured by the rate of uptake of oxygen at peak exercise (VO_2peak).  VO_2peak and VO_2max are the most precise measures of physical fitness. I will devote a future Blog to explaining this measurement and how it can be assessed – and how you can measure it for yourself. In this case the mean VO_2peak was 18.8 ml/kg/min.Suffice it to say, the average level for this age group should be about 32 for men and 27 for women. A level of 18.8 would be normal for an 80 year old man and a 70 year old woman.

In brief the members of this group were obese, took very little exercise and were extremely unfit. T2DM is a serious disease (there is no such thing as “mild” diabetes) and brings with it a panoply of ill effects. These include heart attacks, strokes, kidney disease, blindness, amputation, susceptibility to infection and premature mortality.

I wonder how many diabetics are aware of the complications of T2DM and the fact that these are largely preventable by their own efforts? Both the prevention and the treatment of T2DM require a combination of sensible diet and adequate exercise. What this study shows us is that the lack of exercise with subsequent unfitness is a major component of this unholy duo.

1. doi.org/10.2337/dc18-2634