  Blood Pressure (BP) and Heart Rate (HR) provide information on clin-ical
condition along 24h. Both signals present circadian changes due to
sympa-thetic/parasympathetic control system that influence the relationship
between them. Moreover, also the gender could modify this relation, acting on
both con-trol systems. Some studies, using office measurements examined the
BP/HR re-lation, highlighting a direct association between the two variables,
linked to sus-pected coronary heart disease. Nevertheless, till now such
relation has not been studied yet using ambulatory technique that is known to
lead to additional prog-nostic information about cardiovascular risks. In order
to examine in a more ac-curate way this relation, in this work we evaluate the
influence of gender on the BP/HR relationship by using hour-to-hour 24h
ambulatory measurements. Data coming from 122 female and 50 male normotensive
subjects were recorded using a Holter Blood Pressure Monitor and the parameters
of the linear regression fit-ting BP/HR were calculated. Results confirmed
those obtained in previous stud-ies using punctual office measures in males and
underlined a significant relation between Diastolic BP and HR during each hour
of the day in females; a different trend in the BP/HR relation between genders
was found only during night-time. Moreover, the circadian rhythm of BP/HR is
similar in both genders but with different values of HR and BP at different
times of the day.
