When the Outside Temperature Goes Down, a Senior
Citizen’s Blood Pressure Goes Up
Study finds differences over time were larger in
participants age 80 and older
Jan.
12, 2009 – What seems strange, but appears to be true, is a correlation
in senior citizens between the outside temperature and high blood
pressure or hypertension. But, it works in reverse – when the outside
temperature goes down the senior’s blood pressure goes up.
Seasonal variations in blood pressure have been
recognized among the general population for 40 years, according to
background information in the article in the January 12 issue of Archives of
Internal Medicine, one of the JAMA/Archives
journals.
However, few previous studies have looked
specifically at older adults.
Researchers also urging close monitoring of elderly
with hypertension during weather extremes; second study says thinking
ability varies with blood pressure
"Elderly persons may be particularly susceptible to
temperature-related variations in blood pressure," the authors write.
"The baroreflex, which is one of the mechanisms of
blood pressure regulation, is modified in elderly subjects, and it has
been hypothesized that disorders of baroreflex control and enhanced
vasoreactivity [sensitivity of blood vessels] could contribute to the
aging-associated increase in cardiovascular morbidity [illness]."
Annick Alpérovitch, M.D., of the Institut National
de la Santé et de la Récherche Médicale, Paris, and colleagues assessed
the relationship between blood pressure and temperature in 8,801 senior
citizens age 65 or older.
All were part of the Three-City study, conducted in
three French metropolitan areas. Participants’ 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.
High Blood
Pressure
Also called: HBP, HTN,
Hypertension
Blood pressure is the force
of your blood pushing against the walls of your arteries. Each
time your heart beats, it pumps out blood into the arteries.
Your blood pressure is highest when your heart beats, pumping
the blood. This is called systolic pressure. When your heart is
at rest, between beats, your blood pressure falls. This is the
diastolic pressure.
Your blood pressure reading
uses these two numbers, the systolic and diastolic pressures.
Usually they are written one above or before the other. A
reading of
● 120/80 or lower is
normal blood pressure
● 140/90 or higher is
high blood pressure
● 120 and 139 for the top
number, or between 80 and 89 for the bottom number is
prehypertension
High blood pressure usually
has no symptoms, but it can cause serious problems such as
stroke,
heart failure,
heart attack and
kidney failure. You can control high blood pressure through
healthy lifestyle habits and taking medicines, if needed.
Both systolic (top-number) and diastolic
(bottom-number) blood pressures differed across the four seasons and
across the distributions of outdoor temperatures.
Average systolic blood pressure was 5 millimeters
of mercury higher in winter than in summer. High blood pressure—defined
as a systolic blood pressure of 160 millimeters of mercury or higher, or
a diastolic blood pressure of 95 millimeters of mercury or higher—was
detected in 33.4 percent of participants during winter and 23.8 percent
during summer.
On average, each individual’s blood pressure
decreased between the initial and follow-up measurements. This decrease
was also strongly correlated with outdoor temperature.
"The higher the temperature at follow-up compared
with baseline, the greater the decrease in blood pressure," the authors
write.
These differences over time were larger in
participants age 80 and older.
"Mechanisms that could explain the association
between blood pressure and temperature remain undetermined," the authors
continue.
The sympathetic nervous system (which helps control
involuntary actions, such as stress response) is activated and the
hormone catecholamine is released in response to cold temperatures,
which may increase blood pressure by speeding the heart rate and
decreasing the responsiveness of blood vessels, they suggest.
"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 write.
It may explain well-established seasonal variations
in illness and death from stroke, aneurysm ruptures and other vascular
diseases.
"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."
Keep up with the latest news for senior citizens, baby
boomers
Jan.
12, 2009 – What seems strange, but appears to be true, is a correlation
in senior citizens between the outside temperature and high blood
pressure or hypertension. But, it works in reverse – when the outside
temperature goes down the senior’s blood pressure goes up.