Blood pressure variations linked to outdoor temperature

January 17th, 2009 - 1:58 pm ICT by ANI  

Washington, January 17 (ANI): A French study has revealed that there is a strong co-relation between blood pressure and outdoor temperature.
Published in the Archives of Internal Medicine, the study suggests that during periods of extreme temperatures, careful monitoring of blood pressure and antihypertensive treatment “could contribute to reducing the consequences of blood pressure variations in the elderly.”
Upon monitoring 8801 participants over the age of 65 in the French Three-City study, the researchers found that systolic and diastolic blood pressure values differed significantly across the four seasons of the year and according to the distribution of outdoor temperature.
They said that the higher the temperature, the greater the decrease in blood pressure.
The researchers also observed that changes in blood pressure were greater in subjects 80 years or older than in younger participants.
Participants in the Three-City study were from Bordeaux, Dijon and Montpellier. Their blood pressure was measured at the beginning of the study, starting in 1999, and again about two years later.
Outdoor temperatures on the day of measurement were obtained from local meteorological offices.
“Although our study does not demonstrate a causal link between blood pressure and external temperature, the observed relationship nevertheless has potentially important consequences for blood pressure management in the elderly,” the authors note.
“Because the risk of stroke or aneurysmal rupture is highest in the elderly, improved protection against these diseases by close monitoring of blood pressure and antihypertensive medication when outdoor temperature is very low could be considered,” they state.
Speaking on behalf of the European Society of Cardiology (ESC), Professor Frank Ruschitzka from the University Hospital, Zurich, says that the study reaffirms the place of the elderly as a target group for blood pressure monitoring.
“The elderly, especially the increasing number of octogenarians, should not be neglected. They need extra care, and will benefit from monitoring and appropriate treatment. This study emphasises the need for year-round vigilance,” Ruschitzka says.
The researcher says that one possible explanation for the study findings lies in the emerging link between vitamin D and blood pressure.
Ruschitzka points out that the elderly, especially those in care homes, are subject to vitamin D deficiency, largely as a result of their limited exposure to sunlight, and vitamin D deficiency can predispose to hyptertension via activation of the renin-angiotensin-aldosterone system.
“The benefit of sunlight on vitamin D levels in the elderly is under appreciated. Fifteen minutes exposure to sunlight can produce the equivalent of 2000 international units vitamin D,” Ruschitzka says. (ANI)

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