OBJECTIVE Our aim was to evaluate the effect of the baroreflex mechanism upon peripheral blood volume during sympathetic stimulation by orthostatism. METHODS Nineteen clinically healthy volunteers were included (12 men), 28.4 ± 6.2 years old. Blood pressure was monitored with a Finometer and blood volume with a photoplethysmograph during supine position and orthostatism (15 minutes each), in ...

We used the neck chamber technique to study carotid baroreceptor control of blood pressure in 18 renovascular hypertensive subjects. Carotid baroreceptors were stimulated or deactivated for 2 minutes by applying graded reductions or increases in the neck tissue pressure (NTP) outside the carotid sinuses. The sensitivity of the baroreflex was separately calculated for these two conditions by the...

Patients with postural tachycardia syndrome (POTS) have excessive tachycardia without hypotension during orthostasis as well as exercise. We tested the hypothesis that excessive tachycardia during exercise in POTS is not related to abnormal baroreflex control of heart rate (HR). Patients (n = 13) and healthy controls (n = 10) performed graded cycle exercise at 25, 50, and 75 W in both supine an...

The baroreflex that acts to blunt blood pressure (BP) variations through opposite variations in heart rate should limit the BP increase produced by an emotional challenge. However, relations between baroreflex sensitivity and BP reactivity induced by a psychological stress in a large group of adults have never been firmly established. In 280 healthy men, rest (10 minutes) and stress (5 minutes)...

Volatile anaesthetic agents attenuate arterial baroreflex function, while noxious stimuli may modify baroreflex-induced circulatory responses during anaesthesia. We have examined baroreflex control of heart rate during the entire course of sevoflurane anaesthesia in adult patients undergoing surgical procedures. Baroreflex sensitivity was assessed in nine healthy patients undergoing general ana...

Vitamin D deficiency is associated with increased arterial stiffness. However, the mechanisms underlying this association have not been clarified. The aim was to investigate whether changes in autonomic nervous system activity could underlie an association between 25 hydroxy vitamin D and arterial stiffness. A total of 49 subjects (age = 60 ± 8 years, body mass index = 26.7 ± 4.6 kg/m², 25 hydr...