ANS	Autonomic nervous system
ASP	Autonomic Symptom Profile
BMI	Body mass index
BPM	Beats per minute
CDC	Centers for Disease Control and Prevention
CDC-SI	CDC Symptom Inventory
COMPASS-31	Composite Autonomic Symptom Scale 31
DBP	Diastolic blood pressure
ES	Effect size
GI	Gastrointestinal
HC	Healthy controls
NASA	National Aeronautics and Space Administration
NMH	Neurally mediated hypotension
MCAM	Multi-site clinical assessment of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)
ME/CFS	Myalgic encephalomyelitis/chronic fatigue syndrome
MFI-20	20-item Multidimensional Fatigue Inventory
OGS	Orthostatic Grading Scale
OH	Orthostatic hypotension
OI	Orthostatic intolerance
PEM	Post-exertional malaise
POTS	Postural orthostatic tachycardia syndrome
PROMIS	Patient-Reported Outcomes Measurement Information System
SD	Standard deviation
SEM	Standard error of mean
SF-36v2	Short Form Health Survey—36-item Version 2
SBP	Systolic blood pressure