Aim: Validation study for the use of a nontransmitting
memory belt for recording interbeat
intervals/heart rate variability (HRV) especially
inside vehicles.
Method: 27 volunteers took part in a 40-minute
examination under laboratory conditions
and/or in a medical ambulance and/or in an
armoured military medical vehicle. In every
examination the volunteers carried a nontransmitting
memory belt (Suunto Memory
Belt) and a wire-lead transferring system
with ECG (Schiller MT-101). Afterwards, the
failure rate, interbeat intervals and the heart
rate variability parameters in time-domain,
frequency-domain and phase-domain of the
two systems were analysed.
Results: The non-transmitting memory belt
showed only a low failure rate (0.55 % of all
heart actions) and a median difference from
the ECG in interbeat intervals of 0.03 ms
± 12.60 ms (0.004 %). The limit of agreement
(LoA) was 98.19 %. The HRV parameters in
time-domain, frequency-domain and phasedomain
showed good agreement of the
two recording systems (limit of agreement
91.23–94.74 %).
Conclusions: This study demonstrated for
the first time the suitability of a non-transmitting
memory belt for recording interbeat
intervals in vehicles. The conformity with a
wire-lead transferring ECG system was very
high. Also, the HRV parameters showed acceptable
correspondence. Thus for scientific
field trials the non-transmitting memory belt
is an acceptable alternative. Further studies
are, however, required to demonstrate
the validity of the HRV parameters at higher
levels of physical activity.
