blood pressure
Blood Pressure and Fitness
High blood pressure, alias hypertension, is a leading killer. It has no respect for sex, occupation, social status or religion. Cardiovascular diseases account for approximately 50 percent of deaths in this country. Not only is hypertension one of the leading cardiovascular illnesses, but it is an ancillary hazard of many other illnesses. People suffering from obesity, heart disease, kidney disease, diabetes, and a long list of other illnesses are susceptible to high blood pressure—and to its complications.
High blood pressure, as well as obesity, can be helped by fitness.
Although no precise blood pressure reading demarcates normal from high, North American adults at rest may be in for trouble if their blood pressure is consistently higher than 140/90. Not so with "low blood pressure." In fact, statistically speaking, persons with "low blood pressure" have a greater life expectancy. "Low blood pressure" is truly "low" when a person is gravely ill and in shock—due to haemorrhage, severe coronary attack, terminal disease, or serious injury. Many normal people have normally low blood pressure readings.
When a physician "reads" blood pressure by means of his "blood pressure cuff" and stethoscope, he arrives at two figures—systole (high) and diastole (low). Thus a normal reading might be 130/80. This indicates that the pressure in the blood vessels is 130 mm. of mercury during the squeezing forward action of blood along the arteries when the heart contracts. When the heart relaxes and while it is being filled before the next contraction or heartbeat, diastole is said to occur. This relaxed state, or diastole, is 80 mm. of mercury in this case.
Blood pressure, whether normal or high, fluctuates widely during the day and is influenced by normal daily occurrences. While these rises and dips are transient and almost without clinical significance, they are important as barometers to indicate the adequacy of an individual’s ability to weather the physical and emotional highs and lows which he experiences.
Effect Of Physical Exercise On Blood Pressure
In the untrained subject, a typical or average response of blood pressure during exercise is to rise—perhaps reaching a maximum of 200/100 after two or three minutes. And this then might persist for the duration of the exertion. This is an average change. It signifies a rise in both systole and diastole, but a greater net difference (by subtraction) between the two. This greater net difference indicates that a greater blood flow is being channelled across the muscles, since a larger pressure gradient is being observed. An increased need for nutrient to the muscles with an increased need to remove unneeded residues of burnt fuels from the muscles makes this seem logical.
The sportsman is much more efficient. His blood pressure too increases during exercise—and to about the same "readings"—for two to three minutes. Then his diastolic pressure tends to drop precipitously, perhaps to a final combined "reading" of 200/10. The pressure gradient between systole and diastole is now greatly increased, making for more efficient perfusion of his muscle mass. An athlete thus does not contract his heart more vigorously (systole), but has educated his heart and arteries to relax more completely (diastole). Exercise has long been known to have a beneficial effect on blood pressure. The flexibility of the blood vessels during exercise is maximal (high systole and low diastole), with a decreased tendency obviously to "hardening of the arteries."
The Effect Of Age On Blood Pressure
Although high blood pressure begins at readings over 140/90, this applies only to North American adults. Normal infants have blood pressures of approximately 75/40. During childhood and adolescence blood pressure gradually rises and it is not until late teens and early twenties that 140/90 becomes the upper limit of normal.
There is a time-honored adage that your blood pressure rises one point per year as you grow older. This is far from true. As the years go by there is a normal tendency toward "hardening of the arteries" (arteriosclerosis). In fact, early evidences of "hardening of the arteries" begin in the twenties and early thirties. As the arteries become "hardened," they necessarily lose their elasticity and flexibility. When the heart contracts, the arteries are less able to "give" or stretch a little, resulting in greater pressure along this more rigid system.
Tags: blood pressure, fitness, exercise, high blood pressure
How Different Conditions Can Effect Your Blood Pressure
The Effect Of Sleep
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
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
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
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 Environment
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
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 Bladder
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.
Tags: blood pressure, health, conditions effect blood pressure
