The cold pressor test induced sympathetic peaks starting 4-26 seconds prior to abrupt temperature changes, suggesting temperature change rather than absolute cold drives autonomic response.
Observational (n=101)
How do sympathetic and parasympathetic activities change dynamically during the cold pressor test in healthy subjects?
Abrupt temperature changes, rather than sustained cold, are the primary drivers of sympathetic excitation and parasympathetic withdrawal during the cold pressor test.
Heart rate variability is a useful clinical tool for autonomic function assessment and cardiovascular disease diagnosis. To investigate the dynamic changes of sympathetic and parasympathetic activities during the cold pressor test, we used a time-varying autoregressive model for the time-frequency analysis of heart rate variability in 101 healthy subjects. We found that there were two sympathetic peaks (or two parasympathetic valleys) when the abrupt changes of temperature (ACT) occurred at the beginning and the end of the cold stimulus and that the sympathetic and parasympathetic activities returned to normal in about the last 2 min of the cold stimulus. These findings suggested that the ACT rather than the low temperature was the major cause of the sympathetic excitation and parasympathetic withdrawal. We also found that the onsets of the sympathetic peaks were 4-26 s prior to the ACT and the returns to normal were 54-57 s after the ACT, which could be interpreted as the feedforward and adaptation of the autonomic regulation process in the human body, respectively. These results might be helpful for understanding the regulatory mechanisms of the autonomic system and its effects on the cardiovascular system.
Peng et al. (Fri,) conducted a observational in Healthy subjects (n=101). Cold pressor test was evaluated on Dynamic changes of sympathetic and parasympathetic activities. The cold pressor test induced sympathetic peaks starting 4-26 seconds prior to abrupt temperature changes, suggesting temperature change rather than absolute cold drives autonomic response.