Inclusion criteria of the RCTs.
|Participant||Adults (aged ≥18) were treated with needle acupuncture with or without electric stimulation|
|Intervention||Trials employed acupuncture as the sole treatment|
|Comparator||Trials compared needle acupuncture with any type of sham acupuncture or no treatment (control)|
|Outcome measures||Trials used spectral analysis of HRV as the outcome measure|