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Diurnal patterns of hemodynamic performance in nonhuman primates
1Gerontology Research Center, National Institute on Aging, Baltimore, Maryland 21224.
The American Journal of Physiology
|November 1, 1987
Summary
This study monitored cardiovascular function in monkeys over 18 hours, revealing that cardiac output decreased and peripheral resistance increased overnight. These changes suggest a nocturnal cardiovascular shift, with lowest cardiac output and highest resistance occurring in the early morning.
Area of Science:
- Cardiovascular Physiology
- Primate Research
- Circadian Rhythms
Background:
- Understanding daily variations in cardiovascular function is crucial for interpreting physiological responses.
- Previous research has established general patterns of diurnal changes in human physiology.
Purpose of the Study:
- To investigate the detailed hourly changes in cardiovascular parameters in a non-human primate model.
- To identify specific patterns of heart rate, stroke volume, cardiac output, and blood pressure over an 18-hour period.
Main Methods:
- Continuous monitoring of heart rate, stroke volume, and intra-arterial blood pressures in four monkeys for 18 hours daily over several weeks.
- Minute-by-minute calculation of mean hemodynamic parameters, followed by hourly averaging and intercorrelation analysis.
Main Results:
- Cardiac output significantly decreased throughout the nocturnal period.
- Total peripheral resistance increased during the night, counteracting the drop in cardiac output and resulting in only a slight decrease in arterial pressure.
- Peak peripheral resistance and nadir cardiac output occurred between 0500 and 0700.
Conclusions:
- A distinct nocturnal cardiovascular adaptation occurs in primates, characterized by reduced cardiac output and elevated peripheral resistance.
- These findings highlight significant circadian variations in cardiovascular regulation with implications for physiological research and understanding health.