To observe the changes in autonomic function in Naval Junior Aviation School（NJAS）students under 0.15 MPa hyperbaric oxygen（HBO）intervention，and to provide a reference for health maintenance in adolescents.

42 NJAS students voluntarily signed up for the research. The HBO intervention was performed by pressurizing cabin air to 0.15 MPa（1.5 ATA）in 5 min，lasting for 60 min，during which period the students were continuously breathing pure oxygen by face masks，and then reducing cabin air pressure to normal in 5 min before the students exiting the cabin. The intervention was once a week and continued for seven weeks. Electrocardiograms were collected before and after the HBO intervention，and heart rate variability（HRV）data were obtained using frequency domain analysis to analyze the changes in autonomic function before and after the intervention.

After 0.15 MPa HBO intervention，the participants’ fastest heart rate decreased from（89.81±15.40）beats/min to（84.44±15.36）beats/min，and the slowest heart rate decreased from（58.02±8.49）beats/min to（54.6 9±7.42）beats/min（P<0.001）；low frequency（LF）power did not change significantly（P=0.478 3）；high frequency（HF）power increased from（965.93±861.05）ms² to（1 282.43±1 119.06）ms²；LF/HF decreased from（2.00±1.11）to（1.65±0.85）；total power（TP）rose from（12 046.91±14 863.16）ms² to（21 161.84±22 321.06）ms²；ultra-low frequency power and very low frequency power were significantly higher；HFnorm and LFnorm were significantly lower，and all the differences were statistically significant（P<0.001）；the changes of HF and LF/HF did not correlate with the times of interventions.

The 0.15 MPa HBO intervention once a week can increase parasympathetic activity，enhance the ability of adjusting autonomic function，and regulate the balance in autonomic nervous system in NJAS students.

Hyperbaric oxygen; Heart rate variability; Autonomic function; Naval Junior Aviation School; Student