Positive correlation between the blood pressure and heart rate response to the cold pressor test and the environmental temperature in older hypertensives.
The aims of our study were to evaluate whether there is any relationship between the environmental temperature and the response to the cold pressor test and if this relationship is different in younger and older hypertensive patients. We studied 100 mild-to-moderate hypertensives, aged 21 to 75 years. In the > or = 45 years group (46 patients) a significant positive correlation between the environmental temperature and the heart rate and blood pressure response to the cold pressor test was found. The relative humidity was not correlated with the response to the cold pressor test, but multiplying the mean temperature and the mean relative humidity enhanced the correlations of the environmental temperature. An increase in the mean temperature for the 20 days before the cold pressor test (the best correlated period) by 10 degrees C correlated with increases in the systolic blood pressure response by 10.5 mm Hg (P = .0195), the diastolic blood pressure response by 8 mmHg (P = .0079), the mean blood pressure by 9 mmHg (P = .0058), and the heart rate response by 3.8 beats/min (P = .0134). In < 45 years patients no environmental relationship of the response to cold pressor test was found. A chronic exposure to low temperatures is correlated with higher blood pressure levels--as previously reported--and, in contrast (but only in elderly), with a lower blood pressure response to acute cold stress. Our findings confirm the higher meteorological dependence of hemodynamics in the elderly, and suggest that the research protocols using the cold pressor test should adjust the response for the previous environmental temperature.
Department of Internal Medicine, Hôpital Broussais, Paris, France.
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Postolache
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Gautier
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Laloux
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Safar
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Benetos
D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D003080:Cold Temperature; D004777:Environment; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D013696:Temperature