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Circadian variation of blood pressure in blacks: influence of age, gender and activity
G A Harshfield1, C Hwang, C E Grim
1Department of Medicine, Charles R. Drew University of Medicine and Science, Memphis, Tennessee.
Insights
Black adults exhibit a circadian blood pressure rhythm with a blunted nocturnal decline. Age, gender, and activity significantly influence blood pressure variations, potentially explaining hypertension prevalence differences.
Area of Science:
- Cardiovascular Physiology
- Chronobiology
- Racial Health Disparities
Background:
- Hypertension is a significant public health concern, particularly in certain racial groups.
- Understanding the daily variations (circadian rhythms) in blood pressure is crucial for managing hypertension.
- Previous research suggests potential differences in blood pressure regulation among racial populations.
Purpose of the Study:
- To investigate the daily patterns of blood pressure in Black adults.
- To identify factors influencing these circadian blood pressure variations.
- To explore how these variations might relate to hypertension prevalence in this population.
Main Methods:
- Utilized ambulatory blood pressure monitoring in 60 Black adults (22 males, 38 females).
- Recorded blood pressure non-invasively over a 24-hour period.
- Analyzed data for time-of-day effects, and the influence of age, gender, and activity levels.
Main Results:
- Diastolic blood pressure showed a significant time-of-day effect.
- Systolic blood pressure levels were influenced by age and gender, but not the diurnal pattern itself.
- Blood pressure was highest during work and similar at home, during sleep, and during miscellaneous activities, indicating a blunted nocturnal decline.
Conclusions:
- Black adults display a circadian blood pressure rhythm characterized by a reduced drop during sleep.
- Age, gender, and daily activities are key factors affecting blood pressure variability.
- These findings may contribute to understanding racial disparities in hypertension prevalence.
Abstract:
The purpose of the present study was to examine the circadian variation of blood pressure in black adults and determine the factors associated with this variation. Ambulatory blood pressure recordings were performed with a non-invasive recorder on 60 black subjects, 22 males and 38 females, with a mean age of 31 +/- 11 years and a mean causal blood pressure of 121/93 mm Hg. Only diastolic blood pressure exhibited a significant time of day effect (P less than 0.05). Age and gender were found to have both independent (r2 = 0.10 for each) and interactive effects (r2 = 0.26) on the level of systolic blood pressure during the day, but did not affect the diurnal pattern per se. Blood pressure at work (128/81 mm Hg) was higher (P less than 0.05) than blood pressure during miscellaneous activities (119/75 mm Hg) or sleep (119/73 mm Hg) but did not differ from blood pressure at home (123/77 mm Hg). Blood pressures at home while awake and during sleep were not different. These data show that blacks have a circadian rhythm of blood pressure which is characterized by a blunted nocturnal decline. In addition age, gender and activity are important determinants of the circadian variation. These results may help to explain racial differences in the prevalence of hypertension.