Actiheart User Manual 5.1.31 (Jun 2022)
80
P1
– P4 are weighting factors. X is used to discriminate between activity and “no
activity”. Y and Z are used to apply HR thresholds in the presence and absence
of activity respectively Y is used to discriminate between walking and running. At
running speeds HR is a very reliable measure of EE whereas activity as
measured by vertical acceleration is less reliable since during running the latter
does not increase linearly with speed. This is reflected by the weighting in Box 1
where P1 is high.
At the other end of the spectrum HR is a poor measure of intensity whereas
movement registration is more reliable and this is reflected by a relatively low
weighting of the HR-EE relationship i.e. P4 is low. Z is used to discriminate
between raised HR due to some true activity in the prese
nce of “no activity” (as
set by X) and raised HR due to other factors. In boxes 2 and 3 movement and
HR are equally weighted.
The HR-PAI relationship and the Activity
–PAI relationships are given by the
group calibration regression equations shown below for adults and children
respectively. These have been derived by walking and running on a treadmill in
studies conducted with the Actiheart (5) (6) (7) and are included in the Actiheart
EE analysis.
NO
P
1
%
*
HR-PAI
1
Relati
(1-P
1
%)
Act-PAI
Above
X
Counts.
min
-1
YES
YES
NO
YES
NO
Above
Y
BPM?
Above
Z
BPM?
P
2
%
*
HR-PAI
2
Relati
(1-P
2
%)
Act-PAI
P
3
%
*
HR-PAI
3
Relati
(1-P
3
%)
Act-PAI
P
4
%
*
HR-PAI
4
Relati
(1-P
4
%)
Act-PAI
