||Salivary alpha-amylase (sAA) is used as a sympathetic (SNS) stress marker, though its release is likely codetermined
by SNS and parasympathetic (PNS) activation. The SNS and PNS show asynchronous changes
during acute stressors, and sAA responses may thus vary with sample timing.
Thirty-four participants underwent an eight-minute memory task (MT) and cold pressor task (CPT).
Cardiovascular SNS (pre-ejection period, blood pressure) and PNS (heart rate variability) activity were
monitored continuously. Unstimulated saliva was collected repeatedly during and after each laboratory
stressor, and sAA concentration (U/ml) and secretion (U/minute) determined.
Both stressors increased anxiety. The MT caused an immediate and continued cardiac SNS activation,
but sAAconcentrationincreasedattask cessationonly (+54%);i.e., whenthere was SNS–PNS co-activation.
During the MT sAA secretion even decreased (-35%) in conjunction with flow rate and vagal tone. The
CPT robustly increased blood pressure but not sAA.
In summary, sAA fluctuations did not parallel changes in cardiac SNS activity or anxiety. sAA responses
seem contingent on sample timing and flow rate, likely involving both SNS and PNS influences. Verification
using other stressors and contexts seems warranted