Type 2 diabetes and weight training: how to build strength to control blood glucose
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In the DARE trial, 22 weeks of weight training lowered glycated haemoglobin in people with type 2 diabetes, and combining it with cardio lowered it even more. Why muscle is key, how much to expect, how to programme strength training according to the guidelines and what precautions to take with medication.
In 2007, the DARE trial, led by Ronald Sigal in Canada, randomly assigned 251 adults aged 39 to 70 with type 2 diabetes to four groups: cardio, weights, both or neither. For 22 weeks they trained 3 times a week. Compared with the control group, glycated haemoglobin (HbA1c) fell by 0.51 points with cardio and 0.38 with weights. And those who did both lowered it 0.46 points more than the cardio-only group and 0.59 more than the weights-only group.
HbA1c reflects average blood glucose over the past few months, and lowering it by half a point is a change your doctor will notice. Here is why muscle matters so much in diabetes, how much you can expect, how to structure strength sessions according to the guidelines and what precautions to take if you use insulin or other drugs that can drop your glucose too far.
Why muscle is key in type 2 diabetes
When it contracts, muscle pulls glucose out of the blood. Glucose enters it through a transporter protein, GLUT4, which is activated in two ways: by insulin and by muscle contraction itself. According to the joint position statement of the American College of Sports Medicine and the American Diabetes Association, coordinated by Sheri Colberg (2010), contraction-driven uptake stays elevated for several hours after training, and insulin sensitivity for longer.
In other words: each strength session opens a route for glucose to leave the blood that relies less on insulin, which works less well in type 2 diabetes. According to the same statement, most of the benefits of exercise in diabetes come through improvements in insulin action, both immediate and long term, and they are achieved with both cardio and strength training.
How much does exercise lower HbA1c?
The meta-analysis by Umpierre and colleagues (2011), with 47 trials and 8,538 patients, gives the best overall picture. Structured exercise, meaning planned sessions rather than just advice to move more, was associated with an average drop of 0.67 points in HbA1c.
| Intervention | Average drop in HbA1c |
|---|---|
| Structured aerobic exercise | -0.73 points |
| Structured strength training | -0.57 points |
| Combined aerobic and strength | -0.51 points |
| Structured exercise over 150 minutes a week | -0.89 points |
| Structured exercise of 150 minutes a week or less | -0.36 points |
| Physical activity advice with dietary advice | -0.58 points |
| Physical activity advice alone | No significant change |
Two useful takeaways. First: telling someone to “move more” is not enough; what works is training with a plan. Second: going beyond 150 minutes a week more than doubles the drop.
Not every trial turns out equally well. In the HART-D trial by Timothy Church (2010), with 262 participants over 9 months, only the group that combined cardio and strength lowered HbA1c significantly (0.34 points). Weights alone did not lower it significantly, although that group lost 1.4 kg of fat and all exercise groups reduced their waist by 1.9 to 2.8 cm. The combination is the safest bet.
How to programme strength training with type 2 diabetes
The 2010 position statement gives very specific guidance, and the 2022 American College of Sports Medicine consensus statement, led by Jill Kanaley, keeps the general idea: regular activity, strength included, and less time sitting.
| Variable | When starting | Goal after about 6 months |
|---|---|---|
| Frequency | At least 2 days a week, not consecutive | 3 days a week |
| Exercises per session | 5-10 for the major muscle groups (upper body, lower body and core) | 8-10 |
| Reps | 10-15 per set, close to fatigue | 8-10 per set |
| Sets | Few, to learn technique | 3 per exercise |
| Load | Whatever allows those reps | 75-80% of 1RM |
A full-body session covers these guidelines without complications: squat or leg press, Romanian deadlift, bench press or push-ups, row, shoulder press, lunges, plank and an arm exercise. If you have never trained, start with the full-body routine and, to combine cardio and strength well in the same week, see cardio and strength together.
The post-meal walking trick
In 2016, Andrew Reynolds and his team at the University of Otago compared two pieces of advice in 41 adults with type 2 diabetes: walk for 30 minutes once a day, or walk for 10 minutes after each main meal. With the same total time, walking after meals lowered post-meal glucose by 12%, and after dinner, the meal with the most carbohydrate and the most sitting afterwards, by 22%.
The 2022 consensus statement stresses the same idea: reduce sitting time and break it up with frequent activity breaks. If you like walking, Japanese interval walking has specific data in diabetes, and how many steps a day shows how much everyday movement adds up.
Precautions: hypoglycaemia, eyes and feet
- Hypoglycaemia: according to the 2010 statement, if you do not use insulin or insulin secretagogues, the risk of exercise-induced low glucose is minimal. With insulin or sulfonylureas such as glibenclamide (glyburide), glipizide or glimepiride, or with nateglinide or repaglinide, there is a risk: you may need carbohydrate beforehand if your glucose is below 100 mg/dl (5.5 mmol/l), and 5 to 30 g during and in the 30 minutes after an exhausting session. Dose adjustments are your doctor's decision.
- Intense sessions: hard intervals or very intense strength work empty muscle glycogen and raise the risk of delayed hypoglycaemia in people using those drugs. They can also raise glucose temporarily straight afterwards.
- Eyes: with uncontrolled proliferative retinopathy, avoid efforts that greatly raise pressure inside the eye, such as maximal loads or holding your breath. If you have retinopathy, get advice before starting.
- Feet: with peripheral neuropathy and no open ulcers, you can do moderate weight-bearing exercise, checking your feet daily and wearing suitable footwear.
You can create a 2- or 3-day strength routine with the Progrevia generator, matched to your level and the equipment you have; spread it over non-consecutive days and add the post-meal walks. The generator does not take diabetes or medication into account, so discuss the plan with your doctor or diabetes nurse if you use insulin. If you also have high blood pressure, see exercise to lower blood pressure.
- Sigal RJ, Kenny GP, Boulé NG, et al. Effects of aerobic training, resistance training, or both on glycemic control in type 2 diabetes: a randomized trial. Annals of Internal Medicine. 2007;147(6):357-369.
- Church TS, Blair SN, Cocreham S, et al. Effects of aerobic and resistance training on hemoglobin A1c levels in patients with type 2 diabetes: a randomized controlled trial. JAMA. 2010;304(20):2253-2262.
- Umpierre D, Ribeiro PA, Kramer CK, 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;305(17):1790-1799.
- Colberg SR, Sigal RJ, Fernhall B, et al. Exercise and type 2 diabetes: the American College of Sports Medicine and the American Diabetes Association: joint position statement. Diabetes Care. 2010;33(12):e147-e167.
- Kanaley JA, Colberg SR, Corcoran MH, et al. Exercise/physical activity in individuals with type 2 diabetes: a consensus statement from the American College of Sports Medicine. Medicine & Science in Sports & Exercise. 2022;54(2):353-368.
- Reynolds AN, Mann JI, Williams S, Venn BJ. Advice to walk after meals is more effective for lowering postprandial glycaemia in type 2 diabetes mellitus than advice that does not specify timing: a randomised crossover study. Diabetologia. 2016;59(12):2572-2578.
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Frequently asked questions
Is weight training good if I have type 2 diabetes?
Yes. In the DARE trial (2007), 22 weeks of weight training lowered HbA1c by 0.38 points compared with the control group, and in the meta-analysis by Umpierre (2011) structured strength training was associated with a 0.57-point drop. Combining it with cardio gives the best results.
How many days a week should I do strength training with diabetes?
The 2010 joint position statement recommends at least 2 days a week, not consecutive, ideally building up to 3. Each session should include 5 to 10 exercises for the major muscle groups.
Can I have a hypo when training?
If you do not use insulin or secretagogues such as sulfonylureas, the risk is minimal. If you do, you may need carbohydrate before or after training and a dose adjustment, which your doctor should decide.
Is cardio or weight training better for diabetes?
Both lower HbA1c, and combining them lowers it the most: in the DARE trial, doing both reduced it 0.46 points more than cardio alone and 0.59 more than weights alone.
Does walking after meals help?
Yes. In the study by Reynolds (2016), walking for 10 minutes after each main meal left post-meal glucose 12% lower than walking for 30 minutes in one go, and 22% lower after dinner.
Informational content based on the available scientific evidence: it does not replace advice from a healthcare professional. If you have an injury or a medical condition, or are pregnant, check with one before changing your training or diet.
