ANS	autonomic nervous system
ECG	electrocardiogram
CFS	chronic fatigue syndrome
HR	heart rate
HRV	heart rate variability
HF	high frequency
LF	low frequency
ME	myalgic encephalomyelitis
RMSSD	root mean square of successive differences between NN intervals
RPE	ratings of perceived exertion
RR	respiration rate
SC	skin conductance
SCL	skin conductance level
SCR	skin conductance responses
ST	skin temperature
W	workload