Does strength training help against insulin resistance?
Strength training probably helps against insulin resistance, although the effect is most strongly demonstrated in combination with endurance training and, for additional weight loss, changes in diet.
Strength training increases the density of a protein in muscles that helps transport sugar into the cell (glucose transporter type 4). Having more of this protein means that muscles respond better to insulin. At the same time, the average blood sugar level over three months (measured as HbA1c) falls and visceral fat around the organs decreases. Multiple studies point to this effect, although the evidence is consistently rated as moderate in strength.
The greatest gains have been documented in people who combine strength and endurance training. An analysis of 20 studies involving more than 1,200 people with type 2 diabetes and excess weight showed that such a combined programme leads to lower blood sugar levels, better blood pressure, fewer inflammatory markers in the blood, and a higher quality of life compared with standard care. The researchers themselves describe the quality of the evidence as moderate and call for more robust follow-up research.
Strength training as a standalone intervention is less convincing when looking at cardiovascular risk factors in people with metabolic syndrome who do not yet have diabetes. A systematic review found no statistically significant effect for that group, but attributes this partly to a lack of available studies. It is therefore too early to say that it does not work in that group; it simply has not been studied enough yet.
Exercise in general, including strength training, improves the insulin sensitivity of muscles independently of weight loss. Some effects even occur without insulin needing to play any role. Weight loss itself provides additional benefit on top of that, but it is best achieved by combining strength training with changes in eating and lifestyle habits, rather than through exercise alone.
Evidence is based on one systematic review/meta-analysis (PMID 38887616) on combined training in type 2 diabetes, one systematic review on strength training in metabolic syndrome (PMID 29783064), and two separate reviews on mechanisms and broader lifestyle interventions (PMID 22777332, 27348753, 33213121). Quality of evidence is moderate; large independent RCTs specifically examining strength training as a standalone intervention are largely absent.
Does strength training work better against high blood sugar than cardio?
Strength training appears to work better than cardio alone in people with diabetes and a normal weight, but in overweight individuals that advantage is less clear and a combination of exercise with diet helps the most.
What is insulin resistance and can I reverse it?
Insulin resistance can in many cases be substantially reversed, and exercising more combined with a healthier diet are the best-evidenced approaches for doing so. Starting early pays off, because the longer the vicious cycle runs, the harder it becomes to break.
How do you measure insulin resistance?
There is no single best method for everyone: the clamp is the most accurate but is only feasible in a specialised setting. For practical use, HOMA or QUICKI from a fasting blood draw are a reasonable starting point, provided the result is compared against population-specific norms.
Does magnesium help with insulin resistance?
There is a reasonable amount of evidence that magnesium has a beneficial effect on insulin resistance, particularly if your magnesium levels are too low. If you are not in a risk group, it is sensible to first check whether you are getting enough through your diet before turning to supplements.
Does strength training help against bone loss (osteoporosis)?
Strength training helps to increase or maintain bone density, but the effect is modest and a reduction in fractures has not yet been demonstrated. Train at high intensity and under supervision for the best results.
Does strength training work as well as medication for osteoporosis?
Strength training demonstrably improves bone density and offers additional benefits that medication does not provide, but the two are not alternatives to each other: when fracture risk is seriously elevated, medication has stronger evidence behind it and cannot be replaced by exercise.