Comparison of high-intensity interval training and moderate-intensity continuous training on cardiopulmonary function, cardiac autonomic function and vascular function in adolescent boys with obesity: A randomized controlled trial

Su ZY, Yu WL, Yan ZW, Ding DD, Fang CC, Luo QL, Liu X, Cao LZ

Question

To compare HIIT and MICT effects on cardiopulmonary function, cardiac autonomic function, endothelial function, vascular elasticity, and weight control in adolescent boys with obesity.

Summary

This assessor-blind randomized trial compared 8 weeks of treadmill HIIT with workload-matched moderate continuous treadmill training in adolescent boys with obesity at a weight-loss camp in China. Both groups improved VO2peak, body weight, BMI, and brachial-ankle pulse wave velocity. HIIT was not superior for VO2peak or weight outcomes, but it produced larger improvements in flow-mediated dilation and selected heart-rate variability measures. No adverse events were reported.

Methodology

Forty-four adolescent boys with obesity recruited from a weight-loss camp in Shenyang, China.
44 participants.
Treadmill exercise.
Work intervals: 10 x 1 min at 85%-95% HRpeak.
Recovery: 10 x 2 min active recovery at 60%-70% HRpeak.
Intensity: 85%-95% HRpeak for hard intervals, Borg RPE target 16-17.
40 min total including 5-min warm-up and 5-min cool-down.
3 sessions/week.
8 weeks.
Assessor-blind, two-arm, parallel randomized controlled trial.
VO2peak, Weight and BMI, Brachial-ankle pulse wave velocity, and Flow-mediated dilation were tracked.

Outcomes

VO2peak

Both groups improved VO2peak: MICT +3.49 +/- 1.53 mL/kg/min and HIIT +4.43 +/- 3.38 mL/kg/min, with no significant between-group difference.

Time p < 0.001; group x time F = 1.404, p = 0.243, partial eta2 = 0.033

Improved

Weight and BMI

Both groups reduced weight and BMI, with no significant between-group differences.

Weight group x time p = 0.230; BMI group x time p = 0.318

Improved

baPWV

Both groups decreased baPWV: MICT -24.59 +/- 25.55 m/s and HIIT -26.90 +/- 30.68 m/s, with no significant between-group difference.

Group x time F = 0.073, p = 0.789, partial eta2 = 0.002

Improved

FMD

Both groups increased FMD, with greater improvement in HIIT: MICT +0.25 +/- 0.46% vs HIIT +1.14 +/- 0.79%.

Group x time F = 20.224, p < 0.001, partial eta2 = 0.330

Improved

Heart-rate variability

HIIT improved HF and LF/HF more than MICT; there were no between-group differences for PNN50, RMSSD, SDNN, TP, or LF.

HF: F = 7.527, p = 0.009, partial eta2 = 0.155; LF/HF: F = 4.740, p = 0.035, partial eta2 = 0.104

Mixed

Adverse events

There were no adverse events in either the HIIT or MICT groups.

No clear change

Insights

For adolescent boys with obesity, 8 weeks of low-volume, supervised treadmill HIIT can improve VO2peak similarly to longer moderate continuous training.
HIIT may provide added endothelial-function and autonomic-balance benefits compared with workload-matched MICT.
Safety and adherence findings depend on screening, supervision, HR monitoring, and low-volume protocol design.
This study does not support claims that HIIT is superior to MICT for weight loss or VO2peak under these matched-workload conditions.

Limitations

Male-only sample
Asian ethnicity and weight-loss camp setting
No biomarker analyses for metabolic and cardiovascular mechanisms
Low-volume HIIT selected because high-volume HIIT was difficult for obese adolescents to adhere to
Three sessions per week did not reach the 150 min/week physical activity guideline threshold
Dietary recommendation talks were provided to all participants, making exercise-only interpretation less clean

Safety

No adverse events in either HIIT or MICT groups.
Exercise intensity, duration, heart rate, and adverse events were recorded during exercise.
Low-volume HIIT was selected partly due to exercise risk, physical fitness, and prior adherence difficulty with high-volume HIIT in obese adolescents.