What is the effect of resistance training (RT) on insulin sensitivity?

Resistance Training Significantly Improves Insulin Sensitivity

Resistance training significantly improves insulin sensitivity in both diabetic and non-diabetic individuals, with benefits lasting from hours to days after exercise sessions. 1, 2

Mechanisms of Action

Resistance training improves insulin sensitivity through several mechanisms:

• Increases GLUT4 protein expression and translocation in skeletal muscle 2
• Enhances skeletal muscle mass, contributing to greater glucose uptake 1
• Improves responsiveness of skeletal muscles to insulin 1
• Increases glycogen synthase activity 1
• Enhances fat oxidation capacity and lipid storage in muscle 1, 2
• Restores metabolic flexibility 2

Evidence-Based Recommendations

Frequency and Intensity

• Perform resistance training at least 2-3 days per week on non-consecutive days 1
• Begin with moderate intensity (60-70% of one-repetition maximum) 3
• Progress to 75-80% of one-repetition maximum for optimal benefits 1
• Avoid allowing more than 2 days to elapse between exercise sessions to maintain insulin sensitivity benefits 1

Volume

• Complete at least one set of 5 or more different resistance exercises 1
• Progress over 6 months to three sets of 8-10 repetitions 1
• Focus on exercises involving large muscle groups 1

Duration of Benefits

• Acute improvements in insulin sensitivity last from 2 to 72 hours after exercise 1
• Combined aerobic and resistance training provides more sustained benefits (up to 14 days) compared to either modality alone 4

Clinical Outcomes

Research demonstrates significant improvements in insulin sensitivity with resistance training:

• A 16-week resistance training program in overweight Latino adolescents increased insulin sensitivity by 45.1% compared to controls, independent of changes in body composition 5
• Middle-aged men with insulin resistance showed improved glucose disposal after three months of dynamic strength training (from 3.0 to 4.0 mg/min/kg) 3
• Twice-weekly progressive resistance training for 16 weeks in older men with newly diagnosed type 2 diabetes resulted in a 46.3% increase in insulin action and 7.1% reduction in fasting blood glucose levels 1

Combined Training Approach

While resistance training alone is beneficial, combining it with aerobic exercise may provide additional advantages:

• Combined aerobic and resistance training may be more effective in improving blood glucose control than either modality alone 1, 4
• The combination approach leads to both acute and sustained benefits in insulin sensitivity 4
• Combined training shows greater improvements in β-cell function and glucose effectiveness 4

Practical Considerations

• Supervised resistance training programs show better compliance and glycemic control outcomes 1
• Individuals with diabetes complications should undergo medical evaluation before beginning a resistance training program 1
• Those using insulin or insulin secretagogues may need to adjust medication dosage or carbohydrate intake to prevent hypoglycemia during exercise 1
• Resistance training of any intensity is beneficial, making it accessible for most individuals 1

Caution

• Individuals with uncontrolled proliferative retinopathy should avoid activities that greatly increase intraocular pressure 1
• Those with peripheral neuropathy should wear proper footwear and examine feet daily 1
• Patients with autonomic neuropathy require careful monitoring due to potential cardiovascular complications 1