The effects of high‐intensity interval training on glucose regulation and insulin resistance: a meta‐analysis

Abstract

Summary The aim of this meta‐analysis was to quantify the effects of high‐intensity interval training (HIIT) on markers of glucose regulation and insulin resistance compared with control conditions (CON) or continuous training (CT). Databases were searched for HIIT interventions based upon the inclusion criteria: training ≥2 weeks, adult participants and outcome measurements that included insulin resistance, fasting glucose, HbA1c or fasting insulin. Dual interventions and participants with type 1 diabetes were excluded. Fifty studies were included. There was a reduction in insulin resistance following HIIT compared with both CON and CT (HIIT vs. CON: standardized mean difference [SMD] = −0.49, confidence intervals [CIs] −0.87 to −0.12, P = 0.009; CT: SMD = −0.35, −0.68 to −0.02, P = 0.036). Compared with CON, HbA1c decreased by 0.19% (−0.36 to −0.03, P = 0.021) and body weight decreased by 1.3 kg (−1.9 to −0.7, P < 0.001). There were no statistically significant differences between groups in other outcomes overall. However, participants at risk of or with type 2 diabetes experienced reductions in fasting glucose (−0.92 mmol L−1, −1.22 to −0.62, P < 0.001) compared with CON. HIIT appears effective at improving metabolic health, particularly in those at risk of or with type 2 diabetes. Larger randomized controlled trials of longer duration than those included in this meta‐analysis are required to confirm these results.

Exercise, fitness, and the gut

“…Moreover, patients should avoid dehydration when exercising to avoid intestinal hypoperfusion. Use of high-intensity interval training in patients with IBD may reveal metabolic benefits similar to those seen in obesity [67] and diabetes [68] but this has not been comprehensively investigated. Also, the protective effect of regular physical activity on bone mineral density in IBD sufferers is largely unknown with a recent meta-analysis identifying only a single suitable exercise-intervention study [69].…”

4. Lifestyle Management:Standards of Medical Care in Diabetes—2018

“…Aerobic activity bouts should ideally last at least 10 min, with the goal of ;30 min/day or more, most days of the week for adults with type 2 diabetes. Daily exercise, or at least not allowing more than 2 days to elapse between exercise sessions, is recommended to decrease insulin resistance, regardless of diabetes type (129,130). Over time, activities should progress in intensity, frequency, and/or duration to at least 150 min/week of moderate-intensity exercise.…”

A comparison of the health benefits of reduced-exertion high-intensity interval training (REHIT) and moderate-intensity walking in type 2 diabetes patients

“…High-intensity interval training (HIT) has been proposed to represent a promising, time-efficient alternative/adjunct to aerobic exercise (Earnest, 2008). Meta-analyses have demonstrated that, compared to aerobic exercise, HIT is more effective at improving insulin resistance (Jelleyman et al, 2015) and V O2max (Milanovic et al, 2015) in healthy sedentary individuals. In T2D patients, HIT has been shown to be associated with improvements in insulin sensitivity (Karstoft et al, 2014), glycaemic control (Little et al, 2011), and endothelial function (Madsen et al, 2015).…”