Physical exercise safe and effective non-pharmacological intervention for type 2 diabetes

Evidence from the rapid systematic literature review supported the effectiveness and safety of physical exercises as non-pharmacological interventions for glycemic control. It showed that resistance, aerobic, and combined training interventions were linked to a reduction in fasting glucose and HbA1c.

There has been a repaid rise in the prevalence of diabetes worldwide, with estimates suggesting an increase from 536.6 million adults in 2021 to 783.2 million in 2045. Type 2 diabetes mellitus is a leading cause of disability-adjusted life years. Its treatment requires a balanced diet, physical exercise, and medication.

Andressa Karoline Pinto de Lima Ribeiro and colleagues from Brazil aimed to determine the relationship between physical training variables - intensity, frequency, type, volume, duration and progression - and glycemic control in individuals with T2DM.

For this purpose, the researchers conducted a rapid systematic literature review on LILACS and PubMed databases. Inclusion criteria were defined using the PICOT strategy. Eligible studies had to assess the impact of exercise parameters on glycemic control indicators, primarily glycosylated haemoglobin (HbA1c).

The review included both randomized and non-randomized clinical trials. The methodological quality of each study was evaluated using the PEDro scale.

18 reports met the inclusion criteria out of 1188 papers initially identified and were included in the analysis comprising 1,228 participants with T2DM. Among them, 1086 were allocated to exercise groups and 412 in non-exercised control groups. Among the studies, 16 were RCTs, and 2 were nRCTs. The age of participants ranged from 43.1, and 68.9 years, and the average intervention duration was 16.8 weeks.

The researchers reported the following findings:

• Eight studies reported no adverse events during the intervention, four reported some minor events (such as back pain, tendinitis, hypoglycemia, or muscle injury), and six (33.3%) did not provide information on adverse events.
• Four articles were considered to have a high risk of bias with scores below 5 on the PEDro scale.
• Fourteen articles had moderate to high methodological quality, with scores ≥ 5 on the PEDro scale.
• HbA1c levels significantly decreased in the included reports, except for two of them. Similar improvements in HbA1c levels were found after HIIT and combined training when compared to aerobic and resistance training.
• Only one study compared high-intensity and moderate-intensity exercise and found that HbA1c levels were reduced in both groups, with a greater reduction after high-intensity training.
• There are divergent results regarding the similar improvement induced in glycemic control after HIIT and moderate-intensity exercise or combined exercise in contrast to the improvements achieved only after HIIT but not moderate-intensity aerobic training.
• A significant reduction in fasting blood glucose was reported after HIIT, moderate-intensity aerobic, resistance, or combined training. Similar reductions in fasting blood glucose were reported when comparing aerobic and resistance training
• Aerobic training and muscular strength training were associated with improvements in cardiorespiratory fitness and muscular fitness, respectively.

The researchers noted that the diversity of the physical exercise intervention protocols investigated in the studies included is an important limitation to generalizing evidence-based practice.

"It is mandatory to call for action to implement large-scale education programs on diabetes prevention and public health policies aimed to include supervised and well-planned exercise programs as an essential part of the primary prevention of T2D," they concluded.

Reference:

Ribeiro, A. K., Carvalho, J. P., & Oliver, N. V. (2023). Physical exercise as treatment for adults with type 2 diabetes: A rapid review. Frontiers in Endocrinology, 14, 1233906. https://doi.org/10.3389/fendo.2023.1233906