Dias KA, et al. – This study investigated the efficacy of a 12–week, high-intensity interval training (HIIT) intervention for increasing cardiorespiratory fitness (CRF) and attenuating adiposity in obese children. Findings revealed that, in comparison with moderate-intensity continuous training (MICT) and nutrition interventions, a 12–week, HIIT intervention was highly effective in increasing cardiorespiratory fitness. This intervention provided cardiometabolic health benefit via increasing CRF, while causing no concomitant reductions in adiposity or blood biomarkers.

Methods

• This study included children with obesity (n = 99, 7–16 years old) who were randomised into a 12-week intervention as follows: (1) HIIT [n = 33, 4 × 4-min bouts at 85–95% maximum heart rate (HR_max), interspersed with 3 min of active recovery at 50–70% HR_max, 3 times/week] and nutrition advice; (2) moderate-intensity continuous training (MICT) [n = 32, 44 min at 60–70% HR_max, 3 times/week] and nutrition advice; and (3) nutrition advice only (nutrition) [n = 34].
• Researchers quantified CRF via a maximal exercise test (VO_2peak) while they used magnetic resonance imaging (MRI), dual-energy X-ray absorptiometry (DXA) and air-displacement plethysmography to assess adiposity.

Results

• Findings demonstrated that HIIT stimulated significant increases in relative VO_2peak compared with MICT (+3.6 mL/kg/min, 95% CI 1.1–6.0, P = 0.004) and the nutrition intervention (+5.4 mL/kg/min, 95% CI 2.9–7.9, P = 0.001).
• However, researchers observed that the intervention had no significant effect on visceral and subcutaneous adipose tissue, whole body composition or cardiometabolic biomarkers (P > 0.05).