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Cardiovascular state changes in simulated work environments.

Stuiver A, Mulder B - Front Neurosci (2014)

Bottom Line: This pattern is accompanied by a strong increase in baroreflex sensitivity while heart rate decreases.This pattern is accompanied by a decrease in baroreflex sensitivity, while heart rate decreases.A substantial part of the effects observed during task performance are regulatory effects and are not always directly related to workload manipulations.

View Article: PubMed Central - PubMed

Affiliation: Neuropsychology, Behavioural and Social Sciences, University of Groningen Groningen, Netherlands.

ABSTRACT
The usefulness of cardiovascular measures as indicators of changes in cognitive workload has been addressed in several studies. In this paper the question is explored whether cardiovascular patterns in heart rate, blood pressure, baroreflex sensitivity and HRV that are found are consistent within and between two simulated working environments. Two studies, were performed, both with 21 participants: one in an ambulance dispatch simulation and one in a driving simulator. In the ambulance dispatcher task an initial strong increase in blood pressure is followed by a moderate on-going increase in blood pressure during the next hour of task performance. This pattern is accompanied by a strong increase in baroreflex sensitivity while heart rate decreases. In the driving simulator study, blood pressure initially increases but decreases almost to baseline level in the next hour. This pattern is accompanied by a decrease in baroreflex sensitivity, while heart rate decreases. Results of both studies are interpreted in terms of autonomic control (related to both sympathetic and para-sympathetic effects), using a simplified simulation of a baroreflex regulation model. Interpretation of the results leads to the conclusion that the cardiovascular response patterns in both tasks are a combination of an initial defensive reaction, in combination with compensatory blood pressure control. The level of compensatory blood pressure control, however, is quite different for the two tasks. This helps to understand the differences in response patterns between the two studies in this paper and may be helpful as well for understanding differences in cardiovascular response patterns in general. A substantial part of the effects observed during task performance are regulatory effects and are not always directly related to workload manipulations. Making this distinction may also contribute to the understanding of differences in cardiovascular response patterns during cognitive workload.

No MeSH data available.


Patterns of autonomic activation for the ambulance dispatch center simulation study. Sympathetic and vagal gain in normalized units.
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Figure 3: Patterns of autonomic activation for the ambulance dispatch center simulation study. Sympathetic and vagal gain in normalized units.

Mentions: The results of the baroreflex model simulation are depicted in Figure 3. For the ambulance dispatcher task sympathetic gain decreases 20% in the first 15 min compared to the baseline. This can be derived from the 20% increase in blood pressure from the first rest to the first task (Figure 1). It is important to note that although it sounds illogical, both in the model and in real life a decrease of sympathetic gain corresponds with increased sympathetic activity. This inverse relationship does not occur for the vagal control loop. After the initial decrease in sympathetic gain, a further decrease toward 30% occurs during the remaining first hour of task performance. In the second half of the task sympathetic gain stays 20% decreased compared to baseline. From the relationship between vagal gain, sympathetic gain and heart rate, given by the model, it can be derived that vagal gain does not change in the first 15 min. The decrease in heart rate from rest to task is therefore in this case mainly due to sympathetic gain changes. The same relationship given by the model suggests that the lower heart rate during task performance is due to an increase in vagal gain, partly compensated by a decrease in sympathetic gain. More specifically, vagal gain increases strongly and gradually with 40% in the remaining part of the first hour. In the second hour it remains constant at an even higher level of about 60% compared to baseline.


Cardiovascular state changes in simulated work environments.

Stuiver A, Mulder B - Front Neurosci (2014)

Patterns of autonomic activation for the ambulance dispatch center simulation study. Sympathetic and vagal gain in normalized units.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4256989&req=5

Figure 3: Patterns of autonomic activation for the ambulance dispatch center simulation study. Sympathetic and vagal gain in normalized units.
Mentions: The results of the baroreflex model simulation are depicted in Figure 3. For the ambulance dispatcher task sympathetic gain decreases 20% in the first 15 min compared to the baseline. This can be derived from the 20% increase in blood pressure from the first rest to the first task (Figure 1). It is important to note that although it sounds illogical, both in the model and in real life a decrease of sympathetic gain corresponds with increased sympathetic activity. This inverse relationship does not occur for the vagal control loop. After the initial decrease in sympathetic gain, a further decrease toward 30% occurs during the remaining first hour of task performance. In the second half of the task sympathetic gain stays 20% decreased compared to baseline. From the relationship between vagal gain, sympathetic gain and heart rate, given by the model, it can be derived that vagal gain does not change in the first 15 min. The decrease in heart rate from rest to task is therefore in this case mainly due to sympathetic gain changes. The same relationship given by the model suggests that the lower heart rate during task performance is due to an increase in vagal gain, partly compensated by a decrease in sympathetic gain. More specifically, vagal gain increases strongly and gradually with 40% in the remaining part of the first hour. In the second hour it remains constant at an even higher level of about 60% compared to baseline.

Bottom Line: This pattern is accompanied by a strong increase in baroreflex sensitivity while heart rate decreases.This pattern is accompanied by a decrease in baroreflex sensitivity, while heart rate decreases.A substantial part of the effects observed during task performance are regulatory effects and are not always directly related to workload manipulations.

View Article: PubMed Central - PubMed

Affiliation: Neuropsychology, Behavioural and Social Sciences, University of Groningen Groningen, Netherlands.

ABSTRACT
The usefulness of cardiovascular measures as indicators of changes in cognitive workload has been addressed in several studies. In this paper the question is explored whether cardiovascular patterns in heart rate, blood pressure, baroreflex sensitivity and HRV that are found are consistent within and between two simulated working environments. Two studies, were performed, both with 21 participants: one in an ambulance dispatch simulation and one in a driving simulator. In the ambulance dispatcher task an initial strong increase in blood pressure is followed by a moderate on-going increase in blood pressure during the next hour of task performance. This pattern is accompanied by a strong increase in baroreflex sensitivity while heart rate decreases. In the driving simulator study, blood pressure initially increases but decreases almost to baseline level in the next hour. This pattern is accompanied by a decrease in baroreflex sensitivity, while heart rate decreases. Results of both studies are interpreted in terms of autonomic control (related to both sympathetic and para-sympathetic effects), using a simplified simulation of a baroreflex regulation model. Interpretation of the results leads to the conclusion that the cardiovascular response patterns in both tasks are a combination of an initial defensive reaction, in combination with compensatory blood pressure control. The level of compensatory blood pressure control, however, is quite different for the two tasks. This helps to understand the differences in response patterns between the two studies in this paper and may be helpful as well for understanding differences in cardiovascular response patterns in general. A substantial part of the effects observed during task performance are regulatory effects and are not always directly related to workload manipulations. Making this distinction may also contribute to the understanding of differences in cardiovascular response patterns during cognitive workload.

No MeSH data available.