The heartrate is a useful indication of intensity level. But it is big differences in maximum heartrate, and therefore also in the recommended heartrate at different intensity levels.
The Polar SmartEdge heartrate-monitor estimates an individual training-zone (65-85% of maximum heartrate), based on the variability of the individuals heartrate. This zone is beneficial for improvement of the aerobic capacity and fat-burning. The variability of heartrate decreases for each person when the intensity increases, and is used by the heartrate-monitor to estimate the persons maximal heartrate.
We wanted to see if this was accurate enough on our test persons.
We tested 25 people divided in two groups. One group was teenagers with congenital heart diseases, the other group was a handball team (girls) 13-14 years of age.
We used a threadmill, analyze-equipment for oxygen consumption and Polar SmartEdge heartrate-monitors.
Our results indicate that Polar SmartEdge estimates an OwnZone which is too low compared to the maximum heartrate results. For both groups we used the heartrate peak values, which is 5-6 strokes lower than maximum heartrate. The OwnZone estimates were also more correct for the group with heart disease, even though their oxygen consumption were still increasing.There are big individual differences, indicating that the traditional 220-age is not good enough.
We think that childrens high heartrate, degree of nervouseness, excitement, and heart diseases, will influence the estimation based on heartrate variability.
Our data indicates that the Polar SmartEdge is of limited use for children, and especially with heart diseases.