From:  Heart rate variability as an objective biomarker for work-related musculoskeletal disorder risk: a cross-sectional study of Hong Kong (China) professionals

 Hierarchical multiple regression predicting pain intensity.

BlockPredictors addedR2ΔR2F for ΔR2p
1Age, gender, work hours0.080.082.940.037
2+ PSS-140.240.1621.38< 0.001
3+ SDNN, RMSSD, MHRR, coherence0.350.114.27< 0.001
4+ FHP index, kyphosis angle0.440.098.31< 0.001

FHP: forward head posture; MHRR: mean heart rate range; PSS-14: Perceived Stress Scale-14; RMSSD: root mean square of successive differences; SDNN: standard deviation of normal-to-normal intervals.