In the last issue of the Journal, this column explored the silent revolution that has occurred in the past few decades regarding the contexts in which diseases arise. We used malaria as an example of one of the many diseases that now rarely occurs in this country and we contrasted malaria with the diseases that are prevalent now in which our bodies seem to be at war with themselves. We used malaria to illustrate that there are two separate contexts to disease–first, the context that makes it more likely one will get the disease (e.g., being exposed to malaria-infected mosquitoes) and the disease itself (the malaria parasite in the red blood cells).
The physiological context in which many of these modern diseases arise is the “stress-response” that heightened physical state in which the body is ready to fight or flee in response to some danger, real or imagined. Scientists used to think that the problems caused by prolonged stress are due to the depletion of the hormones secreted during the stress-response. We now know that the problems caused by stress are not due to the depletion of stress-response hormones, but rather that the stress-response itself causes bodily damage. The stress-response is the body’s way of saving itself in the short-term by providing the strength, focus, and energy necessary to respond to imminent danger. Everything is sacrificed for this immediate goal. However, extended sacrifice of the body’s short-term maintenance systems creates long-term problems.
In this second column on stress, we move from an overview of the stress-response to a closer examination of physiological effects of the stress-response. What is happening to you physically as you gear up for that first trial, go to a trial unprepared, or are sent back to the office by the senior partner to get in those 1800 billable hours? The internal activities of your body shift immediately. Your digestive tract shuts down and your breathing rate skyrockets. Secretion of sex hormones is inhibited, while the hormones epinephrine, norepinephrine, and glucocorticoids pour into your bloodstream.
Central to the stress-response is the change in your cardiovascular response. Blood begins moving faster and with more force. In the face of a maximum stressor, your heart’s output increases over five times. To get more blood to your muscles for fight or flight, the sympathetic nervous system, in conjunction with glucocorticoids, constricts certain major arteries. As a result, blood is delivered with greater speed to certain muscles. At the same time, there is a dramatic decrease in blood flow to unessential parts of your body, including the digestive tract, kidneys, and skin. To conserve body fluids, the brain sends an additional stress-response to the kidneys, telling them to stop the process of eliminating waste and water. Water from the kidneys is re-absorbed into the body. Because water in the bladder cannot be reabsorbed and its weight is an impediment to flight, the message is sent for the bladder to be emptied.
The impact of the stress response on the cardiovascular system is incremental. The body works harder for a while but, if it does so on a regular basis, the cardiovascular system wears out sooner. With the chronic increase in blood pressure that accompanies repeated stress, damage begins to occur at branch points in arteries throughout the body. The smooth inner lining of the vessel begins to tear, scar, and pit. Once this layer is damaged, the fatty acids and glucose that are mobilized in the blood stream by the onset of the stress-response begin to work their way under the vessel lining causing it to thicken. This is how chronic stress causes arteriosclerosis. Heart disease is the number one killer in the United States. Anecdotal but dramatic evidence of the connection between the stress-response and heart disease is the number of times that a cardiac catastrophe occurs when the victim is under substantial stress. Remember Bill Hodgman, one of the prosecutors in the O. J. Simpson trial? He got chest pains and collapsed around the 20th time he jumped up to object during Johnnie Cochran’s witness examinations.
Let’s go from the cardiovascular system to how your body’s energy-making system reacts to stress. Again, the significant point here is that the manner in which stress causes your body to mobilize energy can create conditions favorable to making you sick. The stress-response halts the storage of energy and begins to liquidate energy already stored. The body does this through the release of the stress hormones glucocorticoids, epinephrine, and norepinephrine which cause free fatty acids and glycerol to pour into the circulatory system. On the most basic level, this is inefficient. If you activate the stress response too often, you windup expending so much energy that you tire and become fatigued. With enough stress, diabetes can result.
As we have already mentioned, digestion is quickly shut down during the stress-response. This occurs in the stomach and small intestine. The opposite occurs in the large intestine where the body’s objective, as with the bladder, is to eliminate excess baggage as quickly as possible. The result is diarrhea. The connection between stress, colitis, and irritable bowel syndrome is more complex. Stress appears to worsen both conditions but exactly how it does so is still unclear. For lawyers, these conditions may result from a diet lacking in fiber, whereby a lawyer routinely uses the stress-response to eliminate waste from the colon at the same time the digestive process is stalled in the stomach and small intestine.
Almost no physical system is exempt from the effects of the stress-response, including sex and reproduction. With the onset of stress, the entire sexual hormone secretion system is inhibited. Erections become more difficult for men, and women may find their menstrual cycles become irregular.
One of the things that is so disturbing about the stress-response is its pervasive effect on almost all of the body’s systems. In the next FRIENDS column, we will look at the impact of the stress-response on memory and aging, and discuss what you can do to minimize the detrimental impact of the stress-response.
– by Don Carroll and Ed WardPosted by