anchor.diff:  
   PUFA: polyunsaturated fatty acids
   
  +
  +pvRSA/HF: peak-valley respiratory sinus arrhythmia or high frequency power
  +
   === Q
   
   QC: quality control
  
positive.code: RDW: red cell distribution width
  
  
  RQmax: maximum respiratory quotient during treadmill fitness test
  
  
  
negative.code: S2ESBP: stage 2 exercise systolic blood pressure
  
  
  SDNN: standard deviation of the normal-to-normal inter beat intervals
  
  
  serum TG: serum total triglyceride content
  
  
  