While exercise is pretty much universally recommended as positive factor in health and disease-preventer, there’s a surprising dearth of studies which support this notion. Most of the recommendations regarding exercise have come from ‘epidemiological’ studies which may find associations between, say, activity and better health, but do not prove that it’s the activity is causing better health. Active individuals may, after all, smoke less or eat more healthily than less active individuals, and it may be factors such as these that is responsible for the apparent relationship between activity and enhanced health.
To property gauge whatever benefits exercise may have, what we need are intervention studies. The most obvious design here would be to take a group of individuals and get them to up their exercise, and compare their health in the long term with individuals who remain more sedentary. As with nutrition, such studies are rare compared to the epidemiological stuff, but such studies do come along every so often, and they generally provide a valuable opportunity to get a much more accurate picture about what exercise can do for us, and what it can’t.
Recently, such a study was published, which essentially sought to assess the effect of walking in a group of individuals with type 2 diabetes [1]. The study started out with 102 individuals aged 35-75 who were instructed to walk for 20-30 minutes per day. They were followed for a period of a little less than 18 months, during which their adherence to the programme and health with regard to cardiovascular disease (e.g. heart attack and stroke) was assessed through telephone interview.
During the course of the study, 38 individuals ‘dropped out’ and ceased the exercise programme. The cardiovascular health of these individuals was then compared with that of the individuals who stuck with the programme.
The incidence of cardiovascular disease was about 1½ per cent in individuals who completed the programme. This compared very favourably indeed with the incidence in ‘drop outs’ which was found to be more than 18 per cent. The result was statistically significant, and remained even after the researchers took into account other factors that might affect the result including age.
This study was small and far from perfect in terms of design. Asking people about their exercise habits and disease experience over the phone, for instance, may not give us the most accurate picture of such factors. However, even with these limitations, I do believe this study should allow us to be quite optimistic about the real benefits to be had from regular exercise for type 2 diabetics What I find most pleasantly surprising about this study is the relatively short period of time it took before the benefits of exercise became apparent.
It would be nice to see more exercise intervention studies in the future. Ideally, these should include ‘healthy’ individuals, and should focus on manageable, realistic forms of exercise such as walking. Positive results from such studies and their attendant publicity may just help to inspire sedentary individuals to being more active.
References:
1. Shinji S, et al. Adherence to a Home-Based Exercise Program and Incidence of Cardiovascular Disease in Type 2 Diabetes Patients. Int J Sports Med 2007;28:877-879
