The mental arithmetic task significantly increased both muscle and skin sympathetic nerve activity, while the isometric handgrip and cold pressor tests increased muscle but not skin sympathetic nerve activity.
Cross-Sectional (n=29)
No
Do physical and cognitive stressors differentially affect muscle and skin sympathetic nerve activity in healthy volunteers?
Cognitive stressors like mental arithmetic increase both muscle and skin sympathetic nerve activity, whereas physical stressors primarily increase muscle sympathetic nerve activity.
Absolute Event Rate: 365.6% vs 153.5%
p-value: p=0.0059
PURPOSE: Sympathetic nerve activity towards muscle (MSNA) and skin (SSNA) regulates various physiological parameters. MSNA primarily functions in blood pressure and flow, while SSNA operates in thermoregulation. Physical and cognitive stressors have been shown to have effects on both types of sympathetic activity, but there are inconsistencies as to what these effects are. This article aims to address the discrepancies in the literature and compare MSNA and SSNA responses. METHODS: Microelectrode recordings were taken from the common peroneal nerve in 29 participants: MSNA (n = 21), SSNA (n = 16) and both MSNA and SSNA (n = 8). Participants were subjected to four different 2-min stressors: two physical (isometric handgrip task, cold pressor test) and two cognitive (mental arithmetic task, Stroop colour-word conflict test), the latter of which saw participants separated into responders and non-responders to the stressors. It was hypothesised that the physical stressors would have a greater effect on MSNA than SSNA, while the cognitive stressors would operate conversely. RESULTS: Peristimulus time histogram (PSTH) analysis showed the mental arithmetic task to significantly increase both MSNA and SSNA; the isometric handgrip task and cold pressor test to increase MSNA, but not SSNA; and Stroop test to have no significant effects on changing MSNA or SSNA from baseline. Additionally, stress responses did not differ between MSNA and SSNA in participants who had both sets of data recorded. CONCLUSIONS: This study has provided evidence to support the literature which claims cognitive stressors increase sympathetic activity, and provides much needed SSNA data in response to stressors.
McCarthy et al. (Thu,) conducted a cross-sectional in Healthy volunteers (n=29). Physical and cognitive stressors vs. Baseline was evaluated on Muscle sympathetic nerve activity (MSNA) spikes during the last 50 R-waves of the mental arithmetic task (p=0.0059). The mental arithmetic task significantly increased both muscle and skin sympathetic nerve activity, while the isometric handgrip and cold pressor tests increased muscle but not skin sympathetic nerve activity.