Actiheart User Manual 5.1.31 (Jun 2022)
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Lost Secs
This is the total amount of time during an epoch that the Actiheart could not
adequately count as beat interval and was instead effectively ‘lost’ for the
purposes of measuring heart rate.
Max 1
The longest single IBI recorded during an epoch, in milliseconds.
Max 2
The second longest single IBI recorded during an epoch.
MET
Metabolic Equivalent of Task, a normalised measure of intensity, expressed as a
multiple of resting metabolic rate. So a value of 1 is the minimum level at resting
and higher values signify greater intensity calibrated for the individual’s size.
Min 1
The shortest single IBI recorded during an epoch, in milliseconds.
Min 2
The second shortest single IBI recorded during an epoch.
PAL
Physical Activity Level is the total energy expenditure over a longer period (such
as a day or more) divided by the resting metabolic rate. It is equivalent to the
average MET value, but is of much lower typical values than MET during
exercise due to the longer time averaging.
Quality
A measure of the reliability of IBIs recorded during a calculation epoch. This is
not a standard measure, but allows an objective quantitative decision to be made
about which data might be included in a study.
RMR
Resting Metabolic Rate. The energy which a person will use without performing
any activity at all.
RMSSD
The root mean square of the successive differences of the IBIs.
Sleep HR
Sleeping heart rate, which can be measured from a recording using the tool in
Long Term or Advanced Energy Expenditure. It is used to adjust real heart rate
into a level above sleep to indicate likely intensity. It should be determined from
a recording taken during sleep if accurate energy expenditure results are
required.
SD
Standard deviation of a set of data. On heart rate variability statistics, this refers
to the standard deviation of the set of IBIs.
Still HR
The average heart rate taken during all epochs where there was no movement.
TEE
The Total Energy Expenditure is the total of all components of energy
expenditure. In the Actiheart system it is equal to AEE + RMR + DIT.
Time
The time at the start of a recording epoch. For example, an epoch labelled
9:30:00 is a 30 second recording will be that running from 9:30:00 to just before
9:30:30.
Trimmed
A trimmed recording is one where the start or end has been marked out, usually
because the Actiheart was not worn for these period and it is more convenient to
show results excluding it.
VLF
The component of heart rate variability contained in a Very Low Frequency band.
This is defined within ‘Heart Rate Variability, Standards of Measurement,
Physiological Interpretation, and Clinical Use.’ Task Force of the European
