[Is the white coat effect an alert reaction?]

Area of Science:

• Cardiology
• Physiology
• Hypertension Research

Background:

• The white coat effect (WCE) is a common phenomenon where blood pressure is higher in a clinical setting than outside.
• The physiological basis of WCE, particularly its relationship to the sympathetic and parasympathetic nervous systems, remains incompletely understood.

Purpose of the Study:

• To investigate whether the white coat effect on systolic blood pressure is an alert reaction.
• To compare WCE with systolic blood pressure reactivity during a stress test.
• To analyze the influence of autonomic nervous system activity on WCE and stress-induced blood pressure changes.

Main Methods:

• Cross-sectional study comparing WCE with stress test blood pressure reactivity in 174 subjects (44 hypertensives, 130 normotensives).
• Blood pressure (BP) measured during consultation, over 24 hours, and beat-to-beat during a stress test using Finapress.
• Analysis of sympathetic (LF band of systolic BP) and parasympathetic (HF band of pulse rate) system influences.

Main Results:

• White coat systolic BP was not correlated with pulse rate increase, unlike stress test systolic BP.
• White coat systolic BP was significantly lower than stress test systolic BP in both normotensives and hypertensives.
• Hypertensives showed lower parasympathetic index and a positive correlation between white coat systolic BP and stress test systolic BP, negatively correlated with parasympathetic activity.

Conclusions:

• The white coat effect represents a low-amplitude alert reaction.
• Early alterations in the parasympathetic system are observed in recently diagnosed, untreated hypertensives.
• These findings suggest a link between autonomic dysfunction and the white coat effect in hypertensive individuals.