Stress and Blood Pressure

Over the past one hundred years, life expectancy at birth has almost doubled, from the low forties in 1900 to over seventy by 2000. Comparing the most common causes of death in 1900 to 2000 provides insight into what twentieth-century health technology has accomplished.

Communicable diseases were the three most common causes of death in 1900; in 1996, diet and stress-related diseases accounted for the four most common causes. Diabetes, suicide, chronic liver disease, and accidents all have dietary and stress connections as well.

As the twentieth century came to a close, seven of the top ten causes of death were significantly influenced, if not caused, by stress. Stress is inarguably on the rise, and as stress increases, our health suffers. High blood pressure is caused by stress and is a major factor in heart disease and stroke.

A person who can’t control stress in a healthy way may use alternative stress relievers, such as smoking and excessive eating, or may omit beneficial activities, such as exercise.

These unhealthy habits can themselves contribute to disease, such as the link between smoking and lung cancer, or high blood pressure and being overweight. The word stress has a personal meaning for each of us.

We live in an age of anxiety; just about everyone experiences some level of stress from pressures brought on by a complex, competitive society. Technically, stress is the actual bodily wear and tear caused by these pressures, or stressors.

Stress isn’t necessarily a bad thing. An athlete methodically and purposely stresses her body in training so it will rise to a higher level of performance and the athletic event will not exhaust her.

Other examples of using stress to advantage include the practice sessions of police and firefighters, and the everyday exercise many of us do to stay fit. Planned physical stress, such as sensible exercise, can improve our capacity to handle both physical and emotional stress.

To most of us, however, stress means the everyday emotional challenges that take a toll on our health and general wellbeing. We’ve all overheard someone comment, “He’s getting gray too soon,” or “She looks older than her age.”

Worse yet, when a young person has a heart attack, the comment, “Well, he was under a lot of stress,” is often heard. How we deal with all stress, physical and mental, is based on the fight-or-flight response.

This response, which we share with all warm-blooded animals, enables us to avoid or confront physical danger. With the more subtle emotional challenges, however, it can do more harm than good. You’re walking on a lonely street at night when a man jumps out at you from a doorway.

In an instant, you tense up and either start running or stand and fight. The attacker is a clear challenge—technically, a well-defined stressor. Your autonomic nervous system (which doesn’t include your brain) puts your body into fight-or-flight mode without any conscious thought on your part.

Several very important changes take place in the instant you are confronted by the attacker.

  • Digestion stops. This enables your blood to be directed to your muscles, so you can run or fight, and to your brain, so you can think quickly.
  • Breathing quickens even before you start running or fighting. This puts more oxygen into your lungs for faster transfer to your blood, so your muscles and brain get more energy.
  • Pulse rate quickens, raising blood pressure, which forces more blood to your muscles and brain, delivering extra oxygen that enables energy production.
  • Sweating starts instantly. This dissipates body heat caused by the increased blood flow and energy you’re about to expend.
  • Muscles tense for action, making you ready to run or fight. Tense muscles are better able to withstand physical force, such as a blow or knife wound.
  • Clotting chemicals pour into your blood to ensure that bleeding stops quickly if you are injured.
  • Energy-yielding blood sugar is released for quick energy, and blood and fat is similarly elevated to provide prolonged energy in case you have to keep running or fighting.

An attack is a clear example of a stressful event—pretty much what a person would have faced eons ago if he encountered a large, wild animal. These physiological processes are part of our genetic makeup.

Physical stress causes your body to produce the hormones nor-epinephrine (in large quantity) and epinephrine (in modest quantity), which together are called adrenaline.

Adrenaline causes the increase in heart rate, blood flow, and blood pressure that enables the fight-or-flight response. Athletes warm up before a contest or workout to get their adrenaline flowing, which prepares their bodies for the upcoming ordeal.

The release of both adrenaline and another hormone, cortisol, is triggered by emotional stress. Cortisol prepares us for vigorous physical activity by releasing reserves of energy substances such as protein, fat, and glycogen held in lean tissue for conversion to glucose as an additional prolonged energy source.

Prolonged physical activity burns off the results of this hormonal rush, but in emotionally stress full situations, the blood glucose and fatty acids are not burned off.

Generally, we don’t leave stressful meetings or family arguments and go have a good workout to burn them off; instead, we might go to a business lunch, have a drink or a cup of coffee, or simply sulk.

Each option leaves the body with a serious problem: Elevated blood chemicals that were intended to be dissipated by physical activity. Two insidious by-products of prolonged cortisol elevation are increased stomach acidity and lean tissue breakdown.

Therefore, prolonged emotional stress leads to ulcers and a weakened body, causing your muscle strength to actually decline. That’s why stress and ulcers seem to go together; ulcers are the result of stress that has no other outlet.

A Typical Example

Imagine an examining room in a Pentagon medical clinic. Air Force Colonel Smith, stripped to the waist, is nearing the end of his annual physical. The phone buzzes and the examining physician takes the call.

He hands the phone to Smith: “It’s your adjutant, and he says it’s urgent.” Smith’s adjutant explains to him that a Washington reporter has charged him with misappropriating funds to a major Air Force contractor.

The accusations are so serious that they could destroy Smith’s career. Smith’s stress is of the worst kind: He is trapped and can’t do anything about the situation until he returns to his office.

As Smith speaks into the telephone, the doctor sees anxiety, dismay, and fear cross his face. The doctor realizes that Smith is experiencing extreme emotional stress. He grabs a syringe, takes Smith’s arm, and extracts a blood sample.

After the colonel has been on the phone for fifteen minutes, the doctor gets a second blood sample. He now has three samples: one before the stressful event, one at the beginning of the event, and one after Smith was about fifteen minutes into the stress.

The doctor also took blood pressure and pulse simultaneously with an electronic sphygmomanometer. Smith is a fine physical specimen; six feet, 185 pounds.

He maintains excellent condition by running and working out five times weekly. Here’s what the doctor found when he examined Smith during the call: Before the call, his resting pulse rate was 56 while sitting.

His doctor’s first measurement, about five minutes into the call, showed a pulse of about 84; fifteen minutes later, it was almost 100. His blood pressure at rest was 110/70; five minutes into the call, it was 130/85; fifteen minutes into the call, it was 140/95.

Blood chemistry at five minutes showed twice the normal levels of adrenaline in his blood. His blood sugar had gone from a norm of 80 milligrams to about 100, and there was a rise in free fatty acids.

Fifteen minutes into the call, the adrenaline was more elevated, blood sugar was at 100, free fatty acids were 25 percent above normal, and even his blood cholesterol was 10 percent higher than before the call.

You know from the first chapter that the colonel’s kidneys released renin and the renin-angiotensin-aldosterone system went to work. This caused his body to retain sodium and constrict his peripheral arterioles.

By increasing peripheral resistance, his brain (the main organ) gets more blood. Higher pulse means more blood flow. Elevated blood sugar provides short-term energy; elevated free fatty acids provide energy for him to go a couple of hours.

Increased adrenaline meant that his energy level would remain elevated for hours. If Smith were going to fly into combat, or run five miles, or engage in some other physical activity, he’d be ready!

Instead, all he could do was to have his adjutant pull the appropriate files and notify the correct people of the situation. It would have been best if the colonel could’ve dropped everything and gone for a run.

The run would burn off the extra energy, let the adrenaline stabilize, relax his peripheral arterioles, and return everything, including blood pressure, to normal. Science tells us that when people are faced with this type of emotional stress regularly, they are more likely to have high blood pressure.

Some scientists argue that the increase in blood pressure is the outcome of subtle behavioral changes the person makes under stress. Elevated blood pressure results from a so-called negative adaptation that takes place, which maintains the body in a “ready to fight” state.

Overeating, excessive alcohol, and not finding time for exercise are just a few of the possible stress-related behaviors that compound the problem. The primitive fight-or-flight response is alive and well in the modern environment.

Whether you’re an office worker, bus driver, or are a night-shift nurse, your body responds to challenges just as it would have ten thousand years ago in a camp attacked by looters. Instead of picking up a spear, throwing a rock, or running and hiding, however, you often must hide your emotions.

Though you cover up these stress-triggered biochemical changes, they simmer beneath the surface and take a toll on your health by slowly developing high blood pressure unless you take steps to dissipate their effects and prevent them from happening in the first place.

Whether stress is internal or external, there are things we can do to gain control.

  1. Don’t try to relieve the frustration caused by stress by creating more stress. Don’t drink, snack, smoke, or use chemicals. Tranquilizers will never prevent high blood pressure!
  2. Maintain fitness. A conditioned body copes well with stress.
  3. Mental conditioning for external stress is equally important. Prepare for the worst eventuality and decide how you would handle it. Once you’re ready, what actually occurs will be easy.