The effects of high-intensity interval training on glucose regulation and insulin resistance: a meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of intervention trials
PubMed 26481101 · doi:10.1111/obr.12317
What was done
A systematic review and meta-analysis evaluated the effects of high-intensity interval training (HIIT) on markers of glucose regulation and insulin resistance compared to control conditions (CON) or continuous training (CT). Databases were searched for interventions in adults lasting at least 2 weeks that measured insulin resistance, fasting glucose, HbA1c, or fasting insulin. Dual interventions and participants with type 1 diabetes were excluded. Fifty studies met inclusion criteria.
What was found
HIIT reduced insulin resistance compared with CON (standardized mean difference [SMD] = -0.49, 95% CI -0.87 to -0.12, P = 0.009) and compared with CT (SMD = -0.35, 95% CI -0.68 to -0.02, P = 0.036). Compared with CON, HIIT reduced HbA1c by 0.19% (95% CI -0.36 to -0.03, P = 0.021) and body weight by 1.3 kg (95% CI -1.9 to -0.7, P < 0.001). Overall differences between groups were not statistically significant for other outcomes. In participants at risk of or with type 2 diabetes, HIIT reduced fasting glucose by 0.92 mmol/L (95% CI -1.22 to -0.62, P < 0.001) compared with CON.
Why it matters
This review demonstrates that HIIT improves insulin sensitivity and glycemic markers, outperforming traditional continuous training for insulin resistance, particularly in individuals with or at risk for type 2 diabetes.
Limits
The abstract does not state the total number of participants across the 50 included studies. The inclusion threshold of 2 weeks includes very short-term interventions, and the authors emphasize that larger and longer trials are needed to confirm the findings.
Cited by
- supports Systematic reviews and meta-analyses suggest that vigorous, high-intensity exercise may lead to greater improvements in insulin sensitivity markers than moderate exercise.