6 bpm	6 breaths per minute
AAQ-II	Acceptance and Action Questionnaire-II
ANS	Autonomic Nervous System
BMI	Body Mass Index
HR Diff	Difference between Maximum and Minimum Heart Rate
HF	High-Frequency Component
HRV	Heart Rate Variability
LF/HF	Ratio between the low- and high-frequency bands
LF	Low-Frequency Component
max HR	Maximum Heart Rate
Mean HR	Mean Heart Rate
min HR	Minimum Heart Rate
NN	Intervals between consecutive heartbeats when interference is removed
NN50	Number of NN Intervals differing by more than 50 ms
pNN50	Percentage of NN Intervals differing by more than 50 ms
PNS	Parasympathetic Nervous System
PSS	Perceived Stress Scale
RMSSD	Root Mean Square Difference of the Successive Differences
RR	Intervals between consecutive heartbeats
SDNN	Standard Deviation of NN Intervals
SNS	Sympathetic Nervous System
UCLA	University of California, Los Angeles (Loneliness Scale)
WHO	World Health Organization