Daily Fluctuations in Blood Pressure
As we go through the day our blood pressure just naturally raises and lowers depending on a lot of conditions.
What most people are most interested in is a regular resting blood pressure as high blood pressure and hypertension are a very strong indicator toward present and future heart problems.
Drugstore machines that require you to sit in a chair and put your arm through a cuff are notorious for being poorly calibrated and fairly inaccurate. These measurements should never be used as an indication that something is wrong, or as reassurance that everything is OK.
Changes in blood pressure reflect the body ability to adapt. An increase in blood pressure can be a normal part of daily physiology. Blood pressure can go up in a split second depending on situation.
Mere laughter can raise systolic blood pressure even as high as 15 points in people with otherwise normal blood pressure. Talking does the same thing. Now you know why you should not talk or laugh when testing for blood pressure. You may get a false high blood pressure reading. But what if you constantly have a low reading?
Changes of 25 to 30% during the day are not abnormal — they reflect the fact the body is a dynamic, changeable organism. Many normal things can have large effects on blood pressure.
Walking 20 feet can raise systolic blood pressure by 10 to 15 points. Your stress level, how tight your shoelaces are, what you had for breakfast, and how well you slept last night can all change your blood pressure, too.
The Effect Of Sleep on Blood Pressure
Sleep causes a fall in blood pressure. The maximum depth occurs about two hours after falling asleep. In sound, untroubled slumber a pressure of 130/80 might dip to 100/70. It once was thought that this drop in pressure was the cause of sleep, the reasoning being that a lower pressure delivers less blood to the brain resulting in mental sluggishness and hence sleep.
Now it is known that this blood pressure decline is the result, not the cause, of sleep. As morning approaches, the blood pressure drifts slowly upward as the subject begins the awakening process. Any interference with sound sleep causes the blood pressure to rise.
Effect Of Dreaming on Blood Pressure
Interestingly enough, dreaming about exercise may evoke a blood pressure response similar to that which would be observed if the individual actually were exercising. A good example is that of a person dreaming he is climbing the Washington Monument.
Although sound asleep and involved in no physical activity, except perhaps for involuntary muscular twitches, blood pressure approaches levels that would be “read” if he actually were climbing the monument.
Although in deep sleep with a pressure o£ 100/70, the intrusion of a physically active dream raises the pressure to 180/100, when in real life climbing the monument might bring the reading to 200/104.
The old teaching was that a dream is completed in a split second, that an event in reality requiring half an hour can be compressed in a dream into a fraction of a second.
Doctors recently have discovered that this is erroneous. A dream takes about as long to accomplish as the actual physical act would require. A dream involving prolonged exercise or prolonged anxiety has a prolonged effect on blood pressure.
The clinical importance of this observation is only lately being appreciated. If a patient has a known illness or has an incipient illness which is not recognized because he feels well and has not had a physical examination recently, this may explode into a full-blown setback during the blood pressure elevation of a dream.
One hears of patients who die in their sleep, or who develop a coronary, stroke, acute breathlessness, or palpitations while sleeping. In the latter group, the patient may be able to tell of an “active” dream, which produced high blood pressure long enough to cause trouble.
By affording relaxation and release from tension, physical fitness may decrease the tendency to “active” dreams and promote greater elasticity of the arteries-or at least retard the inevitable “hardening of the arteries” which happens to almost everyone. There is less need to dream about physical exercise for those who are able to achieve this satisfaction while awake.
The Effects Of Eating on Blood Pressure
For fifteen to forty-five minutes following a meal, blood pressure normally rises. This response is temporary. A pressure of 130/80 may climb 10 to 30 mm. of mercury by virtue of a full stomach.
Nationality and Normal Blood Pressure
Nationality makes a difference, too. Chinese, for example, are hypertensive at 125/70, while North Americans can get by at 140/90. The British have significantly higher readings than Egyptians.
The Effect of the Environment on Blood Pressure
People in hot climates average lower pressures than inhabitants of cooler locales. In temperate zones where temperature fluctuates, blood pressures are lower in summer and higher in winter. Moving from one climate to another has an effect. If an Egyptian moves to Britain, his blood pressure rises, but not to the same level as the average Briton. And if a Londoner moves to Cairo, his pressure falls, but it still is slightly higher than that of the average Egyptian.
The Posture and Blood Pressure
Blood pressure is widest when observed in the reclining subject. It closes slightly on sitting, and is narrowest when standing. A pressure of 130/70 while lying down might become 120/80 on standing. This change varies greatly from person to person and is most exaggerated in obese persons.
The Effect of the Bladder on Blood Pressure
Curiously enough and for no good reason, the urinary bladder influences blood pressure. Pressure is lowest when the bladder is empty. As the bladder gradually fills, blood pressure rises. Thus a pressure of 130/80 on an empty bladder may reach 160/90 when the bladder is full enough to send messages of “Please empty.”
During urination, the blood pressure then precipitously drops back to 130/80. People whose bladders are never quite empty may carry a pressure which is slightly higher. After treatment and with the resumption o£ complete bladder emptying the pressure falls to normal levels.
Sitting on a full bladder is not only uncomfortable but bad for the blood pressure.
