Evidence Summary
A 2011 Literature review of 48 articles reported that physical activity can be conducted safely and with minimal hypoglycaemia, however this was from a reported small noumber of articles assessed, and that this requires further study. [1]
A 2019 systematic review of 24 both randomised and non-randomised controlled studies found that hypoglycaemic events were reported in seven studies with collective incidence low. It reported that one study showed high levels of hypoglycaemic events and one showed high levels for the first 2 weeks before this decreased. [2]
A 2020 systematic review found that there was a reduced risk of hypoglycaemia if exercise is performed in the morning rather than in the afternoon, and with a 50% rapid-acting insulin reduction. [3]
A 2018 systematic review reviewing 15 studies investigating the effects of different exercise types on blood glucose levels found that there was no significant difference between intermittent high intensity and continuous exercise on rates of hypoglycaemia. [4]
A 2019 study of 14 participants conducting either High intensity training, continuous moderate intensity training or a control found HIT or 30 minutes of MICT can be carried out after an overnight fast with no increased risk of hypoglycemia or hyperglycemia. [5]
A 2016 study comparing glucose variability between 5 athletes and 5 sedentary patients found that there was an increased risk of hypoglycaemia but not severe hypoglycaemia [6]
A 2017 study investigating 15 participants blood glucose response to varying intensities of exercise in the heat found that type one diabetics are likely to require glucose supplementation to prevent hypoglycaemia, especially at higher work intensities. [7]
A 2017 Literature review noted that aerobic exercise is often associated with a reduction in blood glucose and hypoglycaemia can occur during the recovery period. Athletes should therefore adjust insulin/carbohydrate intake to compensate. [8]
A 2015 study of seven trained individuals doing either HIIT versus moderate continuous exercise while using a novel ultra-long acting insulin found that hypoglycaemia did not occur while using the novel insulin and applying a methodological approach to training using specific lactate turn points to measure intensity. [9]
A randomised cross over prospective study with 13 participants found no statistical significance between aerobic and strength exercise on levels of hypoglycaemia . [10]
A 2020 retrospective Controlled analysis of two independent clinical trials investigating the effect of carbohydrate supplementations versus insulin bolus reduction preexercise to combat hypoglycemia found that Carbohydrate supplementations was superior to bolus insulin reduction. No episodes of hypoglycemia were recorded in the carbohydrate supplementations group whereas four episodes of hypoglycemia were seen in both the control group and the bolus insulin reduction group. [11]
A 2018 study of nine physically active type 1 diabetics investigating the effects of strength exercise before high intensity exercise and vice versa found that the performance of HIIE before SE decreases glycaemia already at the end of first exercise modality, while the reverse order postpones it to the end of second exercise, although HIIE + SE improves glycemic stability throughout recovery. T1DM patients who tend to develop exercise-associated hypoglycemia may perform strength exercises before high-intensity interval exercise in a single session. [12]
Grade B
Recommendation 1
Conclusion
There is some conflicting evidence in the studies presented regarding the incidents of hypoglycemia post exercise. Some studies suggest that there is no risk of hypoglycemia while others suggest there is a risk of hypoglycemia. The evidence seems to weigh towards a risk of hypoglycemia however most studies included here contain relatively small sample sizes. No Studies reported an increased risk of hyperglycaemia.
Various studies report different mechanisms of alleviating hypoglycemia post exercise including the use of carbohydrates supplementation, morning exercise over afternoon exercise Space and novel ultra long acting insulin. These were all individual recommendations from low power studies and therefore wouldn’t be reasonable to pass on to patients at this point.
Patient should be warned of the risk of hypoglycemia and should monitor their blood sugars accordingly titrating carbohydrate intake and insulin use as necessary.
References
[1] – Chimen M, Kennedy A, Nirantharakumar K, Pang TT, Andrews R, Narendran P. What are the health benefits of physical activity in type 1 diabetes mellitus? A literature review. Diabetologia. 2012 Mar;55(3):542-51. doi: 10.1007/s00125-011-2403-2. Epub 2011 Dec 22. PMID: 22189486.
[2] – Wu N, Bredin SSD, Guan Y, Dickinson K, Kim DD, Chua Z, Kaufman K, Warburton DER. Cardiovascular Health Benefits of Exercise Training in Persons Living with Type 1 Diabetes: A Systematic Review and Meta-Analysis. Journal of Clinical Medicine. 2019; 8(2):253. https://doi.org/10.3390/jcm8020253
[3] – Valli G, Minnock D, Tarantino G, Neville RD. Delayed effect of different exercise modalities on glycaemic control in type 1 diabetes mellitus: A systematic review and meta-analysis. Nutr Metab Cardiovasc Dis. 2021 Mar 10;31(3):705-716. doi: 10.1016/j.numecd.2020.12.006. Epub 2020 Dec 13. PMID: 33549457.
[4] – Hasan S, Shaw SM, Gelling LH, et al. Exercise modes and their association with hypoglycemia episodes in adults with type 1 diabetes mellitus: a systematic review. BMJ Open Diabetes Research and Care 2018;6:e000578. doi: 10.1136/bmjdrc-2018-000578
[5] – Scott, S. N., Cocks, M., Andrews, R. C., Narendran, P., Purewal, T. S., Cuthbertson, D. J., … Shepherd, S. O. (2019). Fasted high-intensity interval and moderate-intensity exercise do not lead to detrimental 24-hour blood glucose profiles. Journal of Clinical Endocrinology and Metabolism, 104(1), 111–117
[6] – Assessment of glucose variability in athletic and sedentary patients with type 1 diabetes. Girelli AAssanelli ABonfadini S et al. Diabetes, (2016), A192, 65(Supplement 1). DOI http://dx.doi.org/10.2337/db16-652-860 ISSN 1939-327X
[7] – Dervis, S., Poirier, M. P., Malcolm, J., Kenny, G. P., Boulay, P., & Sigal, R. J. (2017). Blood glucose response during exercise in the heat in adults with type 1 diabetes. FASEB Journal, 31(1 Supplement 1).
[8] – Riddell, M.C., Gallen, I.W., and Smart, C.E. (2017). Exercise management in type 1 diabetes: a consensus statement. Lancet Diabetes Endocrinol., 5(5), pp. 377-390.
[9] – Moser, O., Tschakert, G., Mueller, A., Groeschl, W., Pieber, T. R., Obermayer-Pietsch, B., … Hofmann, P. (2015). Effects of high-intensity interval exercise versus moderate continuous exercise on glucose homeostasis and hormone response in patients with type 1 diabetes mellitus using novel ultra-long-acting insulin. PLoS ONE, 10(8).
[10] – Effects of aerobic versus strength exercise on hypoglycemia incidence in patients with diabetes type 1. Ivandic MCanecki Varzic SGradinjan Centner M et al. Diabetes Technology and Therapeutics, (2021), A187, 23(SUPPL 2). DOI
http://dx.doi.org/10.1089/dia.2021.2525.abstracts
ISSN
1557-8593
[11] – no reference found
[12] – Farinha, J. B., Dos Santos, G. C., Vargas, J. L. F., Viana, L. L., De Souza, A. L. G., & Reischak-Oliveira, A. (2018). Capillary glycaemia responses to strength exercises performed before or after high-intensity interval exercise in Type 1 diabetes under real-life settings. Complementary Therapies in Medicine, 40, 116–119.