Decadal Cycles in the Human Cardiovascular System

Area of Science:

• Chronobiology and Cardiovascular Physiology
• Non-linear time series analysis of physiological data

Background:

• Physiological self-surveillance, including around-the-clock monitoring for decades, has revealed complex temporal patterns.
• Previous research has identified various physiological and environmental cycles, some with non-stationary characteristics.

Purpose of the Study:

• To document the presence and characteristics of long-term (decadal) cycles in systolic and diastolic blood pressure and heart rate.
• To explore the potential of these 'Aeolian' cycles in the diagnosis of Vascular Variability Anomalies (VVAs) and cardiovascular risk assessment.

Main Methods:

• Longitudinal physiologic self-surveillance data from seven authors, including around-the-clock monitoring.
• Non-linear estimation of period uncertainties (τs) and comparison of 95% confidence intervals (CIs) to assess cycle congruence.
• Analysis of selective assortment among individuals, variables, and cycle characteristics (mean, circadian amplitude, acrophase).

Main Results:

• Documented the presence of decadal (around 10-year) and longer 'Aeolian' cycles in blood pressure and heart rate.
• Found congruence between components with periods clustering around 10 years.
• Observed selective assortment in cycle characteristics across individuals and variables.

Conclusions:

• Decadal and longer physiological cycles are present in self-monitoring individuals and may be significant for understanding vascular variability.
• These 'Aeolian' cycles, particularly overswings, show potential as biomarkers for predicting hypertension and cardiovascular events.
• Around-the-clock monitoring is crucial for establishing reference values for differential diagnosis of circadian versus circadecadal overswings and guiding treatment.