Glossary

A glossary of *key* ME-related terms.

H

Heart rate monitor (HRM) - (noun) a device that measures your heart rate / pulse. Typically a chest strap, wrist strap, or mobile phone app. See also Pacing with a heart rate monitor

Heart rate variability (HRV) - a measurement of the specific changes in time (or variability) between successive heart beats. This is related to autonomic and cardiovascular function. See also Pacing with a heart rate monitor

P

post-exertional malaise (PEM)- (noun) a worsening of ME symptoms due to physical or cognitive exertion

post-exertional neuroimmune exhaustion -- see post-exertional malaise

T

Two-day cardiopulmonary exercise test

heart rate monitor (HRM) - A device that measures your heart rate (pulse rate). Heart rate monitors may come as a chest strap, wrist strap, smartwatch, or even as a mobile phone app. Heart rate monitors are often used by ME/CFS patients to pace their exertion, in order to avoid post-exertional malaise (PEM). For more information, see pacing with a heart rate monitor.

heart rate (HR) - the number of times the heart beats within a certain time period, usually a minute

heart rate variability (HRV) - A measurement of the variability of the heart rate over time. When the heart rate is consistent, there will be a low heart rate variability. When the heart rate is constantly changing, there will be a high heart rate variability. Heart rate variability is often used by ME/CFS patients to monitor their autonomic nervous system, as high heart rate variability is associated with the sympathetic nervous system and low heart rate variability is associated with the parasympathetic nervous system.

post-exertional malaise (PEM) - A notable exacerbation of symptoms brought on by small physical or cognitive exertions. PEM may be referred to as a "crash" or "collapse" and can last for days or weeks. Symptoms can include cognitive impairments, muscle pain, trouble remaining upright (orthostatic intolerance), sleep abnormalities, and gastro-intestinal impairments, and others.

cognition Thought processes, including attention, reasoning, and memory.

post-exertional malaise (PEM) - A notable exacerbation of symptoms brought on by small physical or cognitive exertions. PEM may be referred to as a "crash" or "collapse" and can last for days or weeks. Symptoms can include cognitive impairments, muscle pain, trouble remaining upright (orthostatic intolerance), sleep abnormalities, and gastro-intestinal impairments, and others.