3.3. What Influences Blood Pressure?
Blood pressure is influenced by many factors including age, weight, physical conditioning,
past illness, time of day, altitude, activity, and climate, to name just a few. In general, blood
pressure is lower in the morning and increases throughout the day. It is lower in warm
weather, and higher in cold weather.
Physical activity can have a significant short term impact on blood pressure. Work, exercise,
smoking, eating, drinking - even talking, laughing, or crying will all affect a person's blood
pressure.
Your diet, including beverages containing caffeine or alcohol, may affect blood pressure.
Emotional stress can have a dramatic impact on your blood pressure.
Even repeated blood pressure measurements taken without adequate rest between readings
will alter your blood pressure as the vessels in your arm engorge with blood. Many of these
influences are only temporary or short term, though chronic (long term) exposure to some
factors may result in permanently elevated blood pressure levels.
3.4. Does Blood Pressure Vary?
Constantly. An individual's blood
pressure varies greatly on a daily
and seasonal basis. It changes
throughout one's lifetime. It is not
uncommon for systolic pressure to
vary by 40mmHg or more
throughout the course of a single
day! While generally not as
volatile, diastolic pressure can still
vary significantly. In hypertensive
individuals, variations are even
more pronounced. Normally, blood pressure is at its lowest during sleep and rises in the
morning and throughout the day. The chart (page 8) illustrates the fluctuations that could
occur in a typical day.
3.5. What is Hypertension?
Hypertension (high blood pressure) is elevated systolic or diastolic levels. In 90 to 95
percent of the diagnosed cases, the specific causes are unknown, although the condition is
often linked with family history, and lifestyle. This is referred to as essential hypertension.
In the remaining cases, high blood pressure is a symptom of an underlying, often treatable
condition, which if corrected, may normalize blood pressure. This less common type is
known as secondary hypertension. Hypertension, if left untreated, may contribute to kidney
disease, heart attack, stroke, or other debilitating illnesses. The following standards for
assessment of high blood pressure in adults have been established by the Joint National
Committee, 2003.
Range Systolic Diastolic Precaution
Classifications Blood Pressure Blood Pressure Measures
Normal
<120 <80 Monitor regularly
Prehypertension
120 - 139 80 - 99
Contact your physician
––
H Y P E R T E N S I O N
––
Stage 1
140 - 159
90 - 99
Contact your
(Moderate)
physician Immediately
Stage 2
≥
160
≥
100
Contact your
(Severe)
physician URGENTLY
(JNC-7 report: Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure / 2003)
