Biomaterial Database

Absence of endogenous circadian rhythmicity in blood pressure? 1998

G A Kerkhof, and H P Van Dongen, and A C Bobbert

Department of Physiology, University of Leiden, The Netherlands. kerkhof@rullf2.leidenuniv.nl

Currently available evidence reveals a predominant role of exogenous (so-called "masking") factors in the 24 h variation of blood pressure in humans. The existence of a (minor) endogenous circadian factor cannot be excluded, however. This possibility was tested by applying the rigorous unmasking conditions of the constant-routine protocol, that is, strict bed rest in a separate bedroom, total sleep deprivation, constant ambient temperature and illumination, and hourly equicaloric food and liquid intake. Twenty-five normotensive young individuals were subjected to a 26 h constant-routine procedure while hourly measurements were made of their blood pressure and heart rate. Repeated-measures analysis of variance failed to show a significant 24 h variation of blood pressure. The power of this test appeared satisfactorily high (>0.95). Heart rate, however, exhibited a significant circadian pattern, with a range of 6.7 beats/min (10% of the 24 h mean value). Moreover, the timing of the 24 h heart rate curves differed significantly between so-called morning (n = 10) and evening (n = 9) individuals. Mean peak values for the morning-types occurred at 11 AM, for the evening types nearly 6 h later. In conclusion, no evidence was found for the involvement of a circadian oscillator in the regulation of blood pressure.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D001794	Blood Pressure	PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.	Systolic Pressure,Diastolic Pressure,Pulse Pressure,Pressure, Blood,Pressure, Diastolic,Pressure, Pulse,Pressure, Systolic,Pressures, Systolic
D002940	Circadian Rhythm	The regular recurrence, in cycles of about 24 hours, of biological processes or activities, such as sensitivity to drugs or environmental and physiological stimuli.	Diurnal Rhythm,Nyctohemeral Rhythm,Twenty-Four Hour Rhythm,Nycthemeral Rhythm,Circadian Rhythms,Diurnal Rhythms,Nycthemeral Rhythms,Nyctohemeral Rhythms,Rhythm, Circadian,Rhythm, Diurnal,Rhythm, Nycthemeral,Rhythm, Nyctohemeral,Rhythm, Twenty-Four Hour,Rhythms, Circadian,Rhythms, Diurnal,Rhythms, Nycthemeral,Rhythms, Nyctohemeral,Rhythms, Twenty-Four Hour,Twenty Four Hour Rhythm,Twenty-Four Hour Rhythms
D003971	Diastole	Post-systolic relaxation of the HEART, especially the HEART VENTRICLES.	Diastoles
D004780	Environment, Controlled	A state in which the environs of hospitals, laboratories, domestic and animal housing, work places, spacecraft, and other surroundings are under technological control with regard to air conditioning, heating, lighting, humidity, ventilation, and other ambient features. The concept includes control of atmospheric composition. (From Jane's Aerospace Dictionary, 3d ed)	Clean Rooms,Laminar Air-Flow Areas,Controlled Environment,Area, Laminar Air-Flow,Clean Room,Controlled Environments,Environments, Controlled,Laminar Air Flow Areas,Laminar Air-Flow Area,Room, Clean
D005260	Female		Females
D006339	Heart Rate	The number of times the HEART VENTRICLES contract per unit of time, usually per minute.	Cardiac Rate,Chronotropism, Cardiac,Heart Rate Control,Heartbeat,Pulse Rate,Cardiac Chronotropy,Cardiac Chronotropism,Cardiac Rates,Chronotropy, Cardiac,Control, Heart Rate,Heart Rates,Heartbeats,Pulse Rates,Rate Control, Heart,Rate, Cardiac,Rate, Heart,Rate, Pulse
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults
D001510	Bed Rest	Confinement of an individual to bed for therapeutic or experimental reasons.	Bedrest,Bed Rests,Bedrests,Rest, Bed,Rests, Bed