The role of respiratory measures to assess mental load in pilot selection

Abstract

While cardiovascular measures have a long tradition of being used to determine operator load, responsiveness of the respiratory system to mental load has rarely been investigated. In this study, we assessed basic and variability measures of respiration rate (RR), partial pressure of end-tidal carbon dioxide (petCO₂) as well as performance measures in 63 male pilot candidates during completion of a complex cognitive task and subsequent recovery. Mental load was associated with an increase in RR and a decrease in respiratory variability. A significant decrease was also found for petCO₂. RR and respiratory variability showed partial and complete effects of recovery, respectively, whereas petCO₂ did not return to baseline level. Overall, a good performance was related to a stronger reactivity in RR. Our findings suggest that respiratory parameters would be a useful supplement to common measures for the assessment of mental load in pilot selection.

Practitioner Summary: Respiratory measures are a promising yet poorly investigated approach to monitor operator load. For pilot selection, we assessed respiration in response to multitasking in 63 candidates. Task-related changes as well as covariation with performance strongly support the consideration of respiratory parameters when evaluating reactivity to mental load.

Keywords:

• Mental load
• multiple task performance
• respiration rate
• respiratory variability
• end-tidal CO₂

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. Altogether, 5% of the 18 971 plateau values were interpolated. We confirmed our reported findings by reanalysing the petCO₂ data including outliers.

2. For validation purposes, all analyses were rerun without cutting the first 30 s. These additional findings replicated our initial results showing that the truncated periods did not leave out crucial information.

3. The dichotomous variable ‘outcome of the cognitive aptitude exam’ was composed of nine different test domains (see above). To validate these findings, we reanalysed our data using the stanine scores of those four test domains that are conceptually related to the experimental multiple task (i.e. working memory, spatial orientation, perception/concentration and multitasking abilities). In line with the reported results, we found significant positive correlations between performance stanine scores and increase in RR from baseline to task (working memory: r = .39, p < .01; spatial orientation: r = .36, p < .01; perception/concentration: r = .32, p < .05; multitasking abilities: r = .30, p < .05) as well as decrease in RR from task to recovery period (working memory: r = .39, p < .01; spatial orientation: r = .38, p < .01; perception/concentration: r = .26, p < .05; multitasking abilities: r = .44, p < .001).