Exercise in the role of Diabetes Management
Exercise is important in the control of type 2 diabetes. There is a clear link with obesity, inactivity and type 2 diabetes1,2 with 85% of people diagnosed with type 2 diabetes overweight or obese.3 The prevalence of type 2 diabetes is increasing annually with 4% of the UK population, or 2.8 million people diagnosed,4 but it is likely that similar proportions are undiagnosed.5,6 Weight gain, especially with central fat accumulation, as indicated by a high waist circumference (Table 1), is associated with impaired glucose tolerance (IGT) and type 2 diabetes.7 Obesity in persons with diabetes is also associated with poorer control of blood glucose levels, blood pressure and cholesterol.8
Increased physical activity and improved diet can delay or even prevent the progression of insulin insensitivity from IGT to overt type 2 diabetes.9 Insulin resistance is an important pre-cursor to type 2 diabetes, and in its early stages is reversible by weight loss and/or an increase in physical activity.10 The metabolic abnormalities of established type 2 diabetes, including hyperglycaemia, hyperinsulinaema and dyslipidaemia can be improved by an increase in physical activity. Once again these benefits are greatest when this behaviour change is made early in the progression from insulin insensitivity to type 2 diabetes requiring medication.11
Physical activity appears to:
- reduce the activity of the pancreatic B-cells and makes cellular tissues more sensitive to insulin.12,13
- increase the rate at which glucose is taken into the muscles, independent of the activity of insulin.14
- improve cardiovascular health and aids weight management.4
For weight management, Table 2 provides an estimate of the number of calories which can be burned for a 60kg or 120kg person for 30 minutes. For many activities, these can be broken down into 10 minute chunks. Levels of both glucose and insulin in the bloodstream fall after any form of activity.
The National Institute of Clinical Excellence (NICE) and Scottish Intercollegiate Guidelines Network (SIGN) recommend that weight management programmes include dietary, behaviour change and physical activity.4,15 Even in the absence of weight loss, exercise has the potential to improve glucose tolerance.9 In the Diabetes Prevention Programme (DPP), and the Finish Diabetes Prevention Study a weight loss of 5-7% along with an increase in physical activity (brisk walking for 150mins per week), in a cohort of subjects with IGT reduced the incidence of type 2 diabetes by 58%.9,16
Individuals with type 2 diabetes are encouraged to participate in physical activity to improve glycaemic control.17 Both resistance exercise and aerobic exercise have been shown to prevent and modify insulin resistance, with improvements in glucose metabolism of between 11-36%.18,19 Walking and cycling levels are associated with a reduced risk of type 2 diabetes, with those individuals who walk or cycle to work less likely to develop the condition.20,21
The SIGN 116, Management of Diabetes guidelines recommend that advice about physical activity, should be specifically tailored to an individual with diabetes, highlighting the impact this has on glucose management.17 A gradual introduction and initial low intensity of physical activity with slow progressions in volume and intensity should be recommended for sedentary persons with diabetes. The walking programme in the physical activity booklet would be ideal (Table 3). Aerobic, endurance exercise is usually recommended. Resistance exercise with low weights and high repetitions are also beneficial.22 A combination of both aerobic and resistance exercise appears to provide optimal improvement in glycaemic control.23
Almost everyone would benefit from being a little more active, especially those diagnosed with, or at risk of type 2 diabetes. The benefits to overall health of increasing daily routine activities such as housework or walking, or more structured exercise such as swimming cannot be underestimated.
References
1. SIGN 115. Management of obesity. A national clinical guideline. Edinburgh, Scotland. Scottish Intercollegiate Guidelines Network, 2010
2. The Counterweight Project Team. The Counterweight Programme: Prevalence of CVD risk factors by body mass index and the impact of 10% weight change. Obes Res Clin Pract 2008; 2:15-27
3. Centre for disease control and prevention. Prevalence of overweight and obesity among adults with diagnosed diabetes. United States 1988-1994 and 1999-2002. MMWR. Morbidity and mortality weekly report. 2004. 19; 53(45). 1066-8.
4. http://www.diabetes.org.uk/Professionals/Publications-reports-and-resources/Reports-statistics-and-case-studies/Reports/Diabetes-prevalence-2010/
5. Williams DRR, Wareham NJ, Brown DC, Byrne CD, Clark PMS, Cox BD et al. Undiagnosed glucose intolerance in the community: the Isle of Ely project. Diabetic Medicine. 1995: 12, 30-35.
6. Forrest RD, Jackson CA, Yudkin JS. Glucose intolerance and hypertension in North London. The Islington Diabetes Survey. Diabetic Medicine. 1986; 3:338-342.
7. Avenell A et al. Systematic review of the long term effects and economic consequences of treatments for obesity and implications for health improvement. Health Technol Assess. 2004; 8(21):2.
8. Anderson JW, Kendal CW, Jenkins DJ. Importance of weight management in type 2 diabetes: review with meta analysis of clinical studies. J Am Coll Nutr 2003; 2:331-9.
9. Tuomilehto J et al. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. NEJM 2001; 344:1343-49.
10. Ross R, Dagnone D, Jones P, Smith H, Paddags G, Hudson R, et al. Reduction in obesity and related co-morbid conditions after diet induced weight loss or exercise induced weight loss in men: a randomised controlled trial. Annals of Intern Medicine. 2000; 133: 92-103.
11. ADA (2000). American diabetes association diabetes mellitus and exercise position statement. Diabetes Care, 23 Suppl 1.
12. Dohm GL, Sinha MK, Caro JF. Insulin receptor binding and protein kinase activity in muscles of trained rats. Am J Physiology. 1987; 252:E170-E175
13. Devlin J, Ruderman N. Eds. (1995). Amerciaan diabetes association: Diabetes and exercise; the risk profile. In the Health Professionals Guide to Diabetes and Exercise. Alexandria, VA, American Diabetes Association, p3-4.
14. Goodyear LJ, Kahn BB. Exercise, glucose transport and insulin sensitivity. Annual Rev Med. 1998; 49:235-261.
15. NICE Clinical Guideline 43 (2006). Obesity. Guidance on the prevention, identification, assessment and management of overweight and obesity in adults and children. www.nice.org.uk
16. Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. NEJM. 2002; 346:393-403.
17. SIGN 116. Management of Diabetes. A national clinical guideline. Edinburgh, Scotland: Scottish Intercollegiate Guideline Network. 2010.
18. Ryan AS. Insulin resistance with ageing: effects of diet and exercise. Sports Medicine 2000; 30: 327-346.
19. Wallace MB, Mills BD, Browing CL. Effects of cross training on markers of insulin resistance/hyperinsulinaemia. Medicine and science in sports and exercise. 1997; 29: 1170-1175.
20. Wannamethee SG, Shaper AG, Alberti KGM M. Physical activity, metabolic factors and the incidence of coronary heart disease and type 2 diabetes. Archives of Internal Medicine 2000; 160: 2108-2116.
21. Hu FB, Sigal RJ, Rick-Edwards JW, Colditz GA, Solomon CG, Willett WC et al.Walking compared with vigorous physical activity and risk of type 2 diabetes in women. Journal of American Medical Association. 1999; 282: 1433-1439.
22. Dunstan DW, Puddey IB, Beilin LJ, Burke V, Morton AR, Stanton KG. Effects of short term circuit training program on glycaemic control in NIDDM. Diabetes Res Clin Pract. 1998; 40(1):53-61.
23. Thomas DE, Elliott EJ, Naughton GA. Exercise for type 2 diabetes mellitus (Cochrane Review). In: The Cochrane Library, Issue 3, 2006. London. John Wiley & Sons Ltd
24.WHO expert consultation (2004). Appropriate body mass index for Asian populations and its implications for policy and intervention strategies. Lancet 363: 157-63
Tables and Diagrams
Table 1: Health risks associated with waist circumference (WHO 2004)
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Low risk
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Increased risk
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Substantial risk
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Non Asian men
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<94cm
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≥ 94cm
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≥ 102cm
|
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Asian men
|
|
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≥ 90cm
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|
Non Asian women
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<80cm
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≥ 80cm
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≥ 88cm
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Asian women
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|
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≥ 80cm
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Table 2: Calories burned with 30 minutes activity
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Calories burned per 30 minutes
|
|
Body weight
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60kg
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120kg
|
|
Housework-cleaning
Climbing Stairs
Gardening- general
Walking (3 mph)
Carrying small child
|
74
438
118
98
89
|
150
864
240
198
180
|
|
Aerobics low impact
Swimming-leisurely
Dancing
Golf
Resistance weights
(low weight, high repetitions)
|
148
177
105
133
89
|
390
360
207
270
180
|
Table 3: Walking programme
Source: Adapted from the London Central YMCA Training & Development
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Weeks 1-2
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Walk at your normal pace for 5 minutes, then turn around and try to do the return journey in 4 minutes
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Weeks 3 & 4
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Walk at your normal pace for 10 minutes and try and return in 9 minutes
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Weeks 5 & 6
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Walk at your normal pace for 12 minutes and try and return in 11 minutes
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Weeks 7 & 8
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Walk at your normal pace 14 minutes and try and return in 13 minutes
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Weeks 9 & 10
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Walk briskly for 15 minutes and try and return in 14 minutes
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Weeks 11 & 12
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Walk briskly for 16 minutes and try and return in 14 minutes
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