G, haven’t used any of the new systems, but a very long time ago at RAE, the old style stick-on terminals and leads with a tape recorder gave good service (also had a pretty nurse who looked after things).
The interest was in the workload in a range of aircraft / operating roles (Alan Roscoe). This ranged from fighter / ground attack aircraft to more sedate 1-11 and HS 748 in fog flying – auto and manual landing.
Amongst the conclusions was that high ‘g’ levels in fighter aircraft involving physical workload changed the heart rate and masked the mental contribution.
For the fog flying there was some indication of the reverse. A few pilots could elevate their heart-rate in anticipation of a difficult mental task – assessing the visual scene and deciding to land or not. Thus the workload at the time of the task did not indicate any significant change although the pilots reported ‘working hard’.
In this task a better measure of mental workload was to require a verbal description of what was seen and how this related to the pending decision; high workload was reflected by reduced commentary and in the extreme silence.
I don’t recall that this was published, but it was part of the work which culminated in the Bedford Workload Rating Scale. This was used in the fog flying and has been used extensively since with good result.
Although there was considerable simulator work associated with the flight tests above, AFAIR none used heart rate monitoring, all used the rating scale.
I sensed that there was an unwritten belief that simulation could not generate the stress / workload associated with a real operation, thus there would be little meaningful change in heart rate – it’s all in the mind. This of course begs the question why the workload ratings in the simulator correlated reasonably well with actual flying.