Evidence summary (Updated 2022)
The beneficial effect of physical activity in people with type 2 diabetes is well documented. There is international consensus that physical activity comprises one of the three cornerstones of treatment together with dietary modification and medication [1-4].
Structured programmes, lasting a minimum 12 weeks, of 150 minutes moderate intensity exercise per week have been shown to be associated with a greater benefit (reduction in HBA1c of 0.9%) than exercise for less than 150 minutes per week (reduction in HBA1c of 0.4%). Those with higher baseline HBA1c stand to gain the most from exercising, with greatest HBA1c reductions shown with exercise [4].
Both structured, supervised exercise programmes and less structured, unsupervised physical activity programmes (of variable activity type and mode of delivery) are effective for improving glycaemic control in people with type 2 diabetes [2,4,5]
Both aerobic and resistance training improve glycaemic control and have positive metabolic effects, however combined exercise programs give the greatest improvement in HBA1c levels [2,4,5]. High Intensity Interval Training (often referred to as HIIT) improves glycaemic control compared to control but not compared to aerobic training [6].
Recent reviews have shown that physical activity is linked with: improving insulin sensitivity; increasing mitochondrial content (size and density), and protects against insulin resistance by increasing the capacity of mitochondria to oxidise fats and their derivatives.[7].
A number of studies have shown that glycemic control measured through HbA1c can be improved with exercise. Certain exercises such as combined aerobic and resistance training promote greater benefits over other forms of exercise by improving beta cell function which is linked to improved glucose control[8]. Combined aerobic and resistance exercise was more efficacious than aerobic exercise alone in improving HbA1c [9,10]
Quality of Evidence
Grade A – High Quality
Strength of recommendation
Grade 1 – Strong recommendation
Conclusion
Recent evidence review confirms that combined aerobic and resistance exercise can be strongly recommended to most people as evidence suggests exercise improves HbA1C by better regulating glucose uptake and glycemic control.
References:
[1] Boule NG, Haddad E, Kenny GP, Wells GA, Sigal RJ. Effects of exercise on glycemic control and body mass in type 2 diabetes mellitus: a meta-analysis of controlled clinical trials. JAMA 2001: 286: 1218–1227.
[2] Thomas D, Elliott EJ, Naughton GA. Exercise for type 2 diabetes mellitus. Cochrane Database of Systematic Reviews 2006, Issue
[3] Wing RR. Long-term effects of a lifestyle intervention on weight and cardiovascular risk factors in individuals with type 2 diabetes mellitus: four-year results of the Look AHEAD trial. Arch Intern Med. 2010 Sep 27;170(17):1566-75
[4] Umpierre D, Ribeiro PA, Kramer CK, Leitão CB, Zucatti AT, Azevedo MJ, Gross JL, Ribeiro JP, Schaan BD. 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
[5] Sigal, R.J., Kenny, G.P., Boulé, N.G., Wells, G.A., Prud’homme, D., Fortier, M., Reid, R.D., Tulloch, H. (2007) Effects of aerobic training, resistance training, or both on glycaemic control in Type 2 diabetes: a randomised trial. Annals of Internal Medicine; 147(6): 357-369251
[6] Jelleyman C, Yates T, O’Donovan G, Gray LJ, King JA, Khunti K, Davies MJ. The effects of high-intensity interval training on glucose regulation and insulin resistance: a meta-analysis. Obes Rev. 2015 Nov;16(11):942-61.
[7] Joseph J. et al Review article: EXERCISE, CAMKII, AND TYPE 2 DIABETES EXCLI Journal (2021);20:386-399 https://doi.org/10.17179/excli2020-3317
[8] Curran M. et al The benefits of physical exercise for the health of the pancreatic 𝜷-cell: a review of the evidence Experimental Physiology (2020).105:579–589 https://physoc.onlinelibrary.wiley.com/doi/pdfdirect/10.1113/
[9] Sarah M. Janssen, Denise M. Connelly. The effects of exercise interventions on physical function tests and glycemic control in adults with type 2 diabetes: A systematic review. Journal of Bod- ywork and Movement Therapies Vo 28, 2021,Pages 283-293. https://doi.org/10.1016/j.jbmt.2021.07.022
[10] Edoardo Mannucci, Allegra Bonifazi, Matteo Monami. Comparison between different types of exercise training in patients with type 2 diabetes mellitus: A systematic review and network metanalysis of randomized controlled trials. Nutrition, Metabolism and Cardiovascular Diseases,Volume 31, Issue 7, 2021,Pages 1985-1992. https://doi.org/10.1016/j.numecd.2021.02.030.