Exercise in the management of type 2 diabetes

• there is now wide acceptance of the importance of increasing physical activity in the management of Type 2 diabetes
  
  
• exercise serves to reduce body weight and increase insulin sensitivity
  
  
• exercise such as a brisk walk of a mile every day confers some benefit - however advanced age or physical disability often preclude this
  
  
• a meta-analysis by Boule et al reveals that three 45 minute moderate intensity aerobic workouts per week (similar to the activity goals for the treatment of obesity (2)) can reduce HbA1c concentrations to a degree sufficient to reduce risk for myocardial infarction by 9% and microvascular complications by 24%, according to the UK Prospective Diabetes Study Group data (3)
  
  
• in consideration of: reviewing the benefits of aerobic activity for patients with type 2 diabetes have repeatedly confirmed that compared with patients in sedentary control groups, aerobic exercise improves glycemic control, insulin sensitivity, oxidative capacity, and important related metabolic parameters (8). Aerobic exercise is a well-established way to improve HbA1c, and strong evidence exists with regard to the effects of aerobic activity on weight loss and the enhanced regulation of lipid and lipoprotein metabolism (8)
  
  
  • aerobic exercise -
  • high-intensity interval training (HIIT) - consists of very short bursts of very high-intensity exercise interspersed with periods of recovery - and type 2 Diabetes
    
    • study evidence has shown that high-intensity aerobic interval training improves aerobic fitness and HbA1c among persons diagnosed with type 2 diabetes (4)
  • resistance training - study evidence has shown a threefold greater reduction in HbA1c in patients with type 2 diabetes ages 60 to 80 compared with nonexercising patients in a control group - was also an increase in lean body mass in the resistance-training group, while those in the nonexercising control group lost lean mass after 6 months (9)
    
    
  • blood pressure effects
    • a systematic review and meta-analysis of randomized controlled clinical trials (RCTs) was undertaken to determine the effects of structured exercise training (aerobic [AER], resistance [RES], or combined [COMB]) and physical activity (PA) advice only on BP changes in patients with type 2 diabetes
      • concluded that AER, RES, and high-intensity combined training are associated with BP reduction in patients with type 2 diabetes, especially in exercise programs lasting more than 150 min/week. PA advice only is also associated with lower BP levels (5)
        
        
  • changes in HbA1c associated with exercise in type 2 Diabetes (6)
    • evidence that exercise training is associated with a reduction in glycated haemoglobin (HbA1c) of 0.67% in people with T2DM, with benefit coming from aerobic or resistance exercise separately and both in combination
      • duration of the structured exercise programmes was also found to be important
        • programmes with an exercise duration of greater than 150 minutes per week were associated with an HbA1c reduction of 0.89%, whereas those with duration less than 150 minutes per week were associated with a reduction of 0.36%. Physical activity advice was also associated with a signifi cant reduction in HbA1c, but only in combination with dietary advice
          
          
  • changes in mortality data
    • meta-analysis of cohort studies coupled with data from a prospective cohort study have suggested that there is a significant benefit, demonstrating an inverse relationship between physical activity and both cardiovascular disease and all-cause mortality (7)

A review notes that "Exercise training, whether aerobic or resistance training or a combination, facilitates improved glucose regulation. High-intensity interval training is also effective and has the added benefit of being very time-efficient.." (8)

https://www.ncbi.nlm.nih.gov/pubmed/28748370Advice re: Medication, Exercise and Type 2 Diabetes is (9):

• "..the concern of blood glucose going low during exercise may be on your mind. In reality, most of the diabetes medication used by people with Type 2 diabetes tends not to cause hypoglycaemia. Diabetes medication which requires extra caution is insulin and a class of drugs called insulin secretagogues (common examples of this include Gliclazide, Glimepiride and Repaglinide). These medications can cause hypoglycaemia during and after exercise (up to 24 hours after an exercise bout)...
  
  
• Insulin and exercise
  • Strategies to prevent hypoglycaemia if using fast-acting insulin:
    • If exercising within two hours of a meal where fast-acting insulin was taken, you may need to consider lowering the insulin dose. However, monitor the effects of exercise on your blood glucose and speak to your diabetes team for advice on appropriate insulin reduction, if this is necessary
    • If exercising before a meal (e.g. exercise before breakfast) then consider reducing the fast-acting insulin dose at the meal eaten after exercise (in this case, breakfast).
• if you use tablets such as Gliclazide and have experienced hypoglycaemia during exercise, have a discussion with your diabetes team as it may be an option to decrease the medication dose on exercise days..."

Metabolic equivalent task (MET) min/week dose and diabetes

• a review (126 studies; n=6718) suggests optimal physical activity dose was 1100 metabolic equivalent task (MET) min/week, decreasing HbA1c from−1.02% to −0.66% in severe uncontrolled diabetes (UDB),−0.64% to−0.49% in UDB,−0.47% to−0.40% in controlled DB &−0.38% to−0.24% in preDB (11)

Reference:

1. Prescribers' Journal (2000), 40 (1), 38-48.
2. Boule NG et al (2001). Effects of exercise on glycemic control and body mass in type 2 diabetes mellitus. A meta-analysis of controlled clinical trials. JAMA, 286, 1218-27.
3. Stratton IM et al (2000). BMJ, 321, 405-12.
4. Helal L et al. High-intensity aerobic interval training improves aerobic fitness and HbA1c among persons diagnosed with type 2 diabetes: considerations regarding HbA1c starting levels and intervention design.Eur J Appl Physiol. 2017 Nov;117(11):2365-236
5. Figueira FR et al. Association between physical activity advice only or structured exercise training with blood pressure levels in patients with type 2 diabetes: a systematic review and meta-analysis.Sports Med. 2014 Nov;44(11):1557-72.
6. Umpierre D et al. Physical activity advice only or structured exercise training and association with HbA1c levels in type 2 diabetes: a systematic review and meta-analysis.JAMA. 2011 May 4;305(17):1790-9.
7. Sluik D et al. Physical activity and mortality in individuals with diabetes mellitus: a prospective study and meta-analysis. Arch Intern Med 2012;172:1285-95.
8. Kirwan JP et al. The essential role of exercise in the management of type 2 diabetes. Cleve Clin J Med 2017 Jul;84(7 Suppl 1):S15-S21. doi: 10.3949/ccjm.84.s1.03.
9. Diabetes UK. Sports nutrition and Type 2 diabetes (Accessed 16/5/20)
10. Dunstan DW, Puddey IB, Beilin LJ, Burke V, Morton AR, Stanton KG. Effects of a short-term circuit weight training program on glycaemic control in NIDDM. Diabetes Res Clin Pract. 1998; 40:53–61.
11. Gallardo-Gómez G et al. Optimal Dose and Type of Physical Activity to Improve Glycemic Control in People Diagnosed With Type 2 Diabetes: A Systematic Review and Meta-analysis. Diabetes Care 19 January 2024; 47 (2): 295–303.