A mathematical modelling analysis of the response of blood pressure and heart rate to submaximal exercise.

OBJECTIVE: According to Golden ratio (GR) and Fibonacci sequence, models of the organisation of various structures can be encountered in biology, medicine, architecture and engineering. Recent studies indicate that GR can be highlighted in the organisation and physiological functioning of the cardiovascular system. The aim of this study was to investigate the cardiovascular homeostasis during rest and exercise testing by determining the GR validity at the dynamic level of systolic and diastolic blood pressure (SBP, DBP) and heart rate (HR) values.

METHODS AND RESULTS: We used data obtained from a cardiovascular testing of a group of 236 young healthy subjects (mean age of 19.35 ± 1.92 years). We realised a double assessment of subjects (HR and BP), at rest and immediately after a six minutes submaximal exercise test (Astrand and Rhyming protocol). The investigated group showed a normal cardiovascular reactivity in subjects. GR harmonic rhythm can be identified in the correlation of hemodynamic parameters of HR and SBP, respectively of SBP and DBP, at rest. The differences between means of the ratios (SBP/HR and SBP/DBP), at rest and after effort, were statistically significant (p < .001), with a large effect size.

CONCLUSIONS: We confirm that the rest state determines the harmonisation of SBP and HR, respectively, of SBP and DBP values, both ratios being very close to GR value. From the perspective of these cardiovascular parameters, the human body is designed to function in the harmonic regime at rest and to temporarily get out of synchronisation during exercise.