OBJECTIVE: To examine whether circulating metabolic responses to low-volume high-intensity interval exercise (LV-HIIE) or continuous moderate-intensity aerobic exercise (CME) differ between white Europeans and South Asians with nondiabetic hyperglycemia (NDH). RESEARCH DESIGN AND METHODS: Thirteen white Europeans and 10 South Asians (combined median (interquartile range) age 67 (60 to 68) years, HbA1c 5.9% (5.8 to 6.1%) (41.0 (39.9 to 43.2) mmol mol-1)) completed three 6-h conditions (sedentary control (CON), LV-HIIE, and CME) in a randomized order. Exercise conditions contained a single bout of LV-HIIE and CME, respectively (each ending at 2 h), with meals provided at 0 and 3 h. Circulating glucose (primary outcome), insulin, insulin resistance index (IRI), triglycerides, and nonesterified fatty acids were measured at 0, 0.5, 1, 2, 3, 3.5, 4, 5, and 6 h. Data were analyzed as postexercise time-averaged area under the curve (AUC) adjusted for age, sex, and preexercise AUC. RESULTS: Glucose was similar in each condition and with ethnicity, with no condition-by-ethnicity interaction (p >= 0.28). However, insulin was lower in LV-HIIE (mean (95% CI) -44.4 (-23.7 to -65.1) mU/L) and CME (-33.8 (-13.7 to -53.9) mU/L) compared with CON. Insulin responses were greater in South Asians (interaction p = 0.03) such that values were similar in each ethnicity during exercise conditions, despite being 33% higher in South Asians during CON. IRI followed a similar pattern to insulin. Lipids were unaffected by exercise. CONCLUSIONS: Reductions in insulin and insulin resistance after acute LV-HIIE and CME are greater in South Asians than in white Europeans with NDH. Further trials are required to examine the longer-term impact of LV-HIIE and CME on cardiometabolic health.
Copyright American Diabetes Association. Reprinted with permission from The American Diabetes Association.

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