Spearman correlation analysis between sleep-related respiratory measures and heart rate variability parameters
| oAHI | RDI | Mean SpO2 | SpO2 nadir | TST95 | ODI | |
| Mean RR interval | −0.15# | −0.18# | 0.15# | −0.23¶ | ||
| SDNN | ||||||
| Mean HR | 0.16# | 0.19# | 0.23¶ | |||
| LF bands | ||||||
| HF bands | 0.22¶ | 0.18# | 0.25¶ | |||
| LF/HF band ratio | 0.17# | 0.17# | −0.23¶ | −0.20¶ | −0.25¶ |
Only significant Spearman correlation coefficients are shown. oAHI: obstructive apnoea–hypopnoea index; RDI: respiratory disturbance index; SpO2: arterial oxygen saturation measured by pulse oximetry; TST95: percentage of total sleep time with SpO2 >95%; ODI: oxygen desaturation index; SDNN: standard deviation of RR intervals (normal sinus-to-normal sinus interbeat intervals); HR: heart rate; LF: low-frequency; HF: high-frequency. #: p≤0.05; ¶: p≤0.01.