Treating diabetes with exercise - what does the evidence say?
Diabetic patients spend up to 40% of the day with excessively high blood sugar levels, which can damage blood vessels and lead to long-term health consequences (Van Dijk et al., 2013). Medication to maintain diabetes is effective to a certain degree, however, studies show that patients still spend up to seven hours per day with abnormally high glucose levels even when drugs are administered (Van Dijk et al., 2013). Clearly, further interventions are needed to minimise the negative effects of diabetes.
What is diabetes?
Diabetes is a chronic disease characterised by relative lack of insulin- a hormone that helps to stabilise blood glucose (sugar) levels. According to Diabetes UK, somebody gets diagnosed with diabetes every two minutes. In Type 1 Diabetes, the body is unable to produce insulin, whereas in Type 2 Diabetes your body does not respond to insulin. That means that although insulin is produced, the body cannot take glucose out from the blood. In particular, muscle is a major tissue that takes glucose out of the blood but it becomes less efficient in Type 2 Diabetes.
Physical activity and prevention of type 2 diabetes
The most powerful way by which to prevent the development of T2D is by living a healthy lifestyle. In a long-term study by Knowler and colleagues (2002), it was shown that diet and active lifestyle combined reduced diabetes incidence by 58% in high risk patients. And importantly, lifestyle changes were more effective than drug administration. But physical activity alone is also a powerful predictor of T2D. Evidence suggests that high levels of physical activity can reduce the risk of developing T2D by 20-30%, with the greatest reductions seen in those who are already at a greater risk- obesity, those with family history or impaired glucose tolerance (Gill & Cooper, 2008). To support that, experimental studies have shown that regular exercise can improve glucose maintenance and insulin sensitivity by 43% in high risk patients (Perseghin et al., 1996). What’s great is that the effect of exercise on improved insulin action can be seen up to several days after exercise (King et al., 1995).
Physical activity as therapy for diabetes
Exercise is not only a crucial way by which to prevent diabetes, but also plays an important role in treating diabetes. It does so through three main mechanisms, all of which result in reducing the glucose levels in the blood. Firstly, the glucose in the blood is directly used as a fuel to power exercise. Secondly, during exercise, muscle contractions stimulate the uptake of glucose from the blood, even when insulin is not present. And thirdly, physical activity promotes short-time increase in insulin sensitivity, which helps to uptake glucose from the blood even after exercise has stopped. All of the above result in removing sugar from the blood, leading to better maintenance of blood glucose levels (Sylow et al., 2016). Indeed, in a study by Van Dijk et al. (2012), 30 T2D patients were randomised into two groups: either no exercise or 60 minutes of cycling exercise. The authors demonstrated that the prevalence of high glucose levels was substantially reduced from 32% of the day to 24% following endurance-type activity. That's almost 2 hours of the day spent with better glucose levels and two hours less damage to your blood vessels!
How much physical activity is enough?
According to the American Diabetes Association, for the most optimal blood glucose control at least 150 minutes of moderate-intensity aerobic physical activity is recommended per week and/or at least 90 min/week of vigorous aerobic exercise. The same applies for resistance exercise too (Van Dijk et al., 2012)! Moreover, although not as effective as high intensity exercise, studies have shown that even light physical activity, such as walking and gardening, can be effective in lowering blood glucose (van Dijk et al., 2013). Exercise should be distributed over at least 3 days per week, with no more than 2 consecutive days without physical activity.
PS! Activity may affect your blood sugar levels both during and after exercise. Regular checking will help you to understand how activity affects your blood sugar levels. Test your levels more often before, during and after any physical activity. Read more about controlling blood sugar levels from here:
TAKE HOME: Even little exercise is beneficial for your health but the more, the better! So, let’s tackle diabetes and get active!
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