Charles Russo M.D., FACCBy definition stress is usually caused by stressor. This may be some external or internal stressor and it can also be real or just perceived. For example: if I know I am going to get chewed out by my boss for something that just happened that is a real stressor; whereas, if I am 5 minutes off my schedule to pick up the dry cleaning and I get anxious that is something that is perceived. It is just like thinking, for instance, that the sales clerk does not really like you.
So what does this stress do to our body? Well, as it turns out, there is a preprogrammed response that all mammals share. It is involuntary and it is initiated in our brain and enhanced by certain glands such as the adrenal gland. It is also, for the most part, involuntary. It is what we all recognize as the "fight or flight" response.
So what does this "fight or flight" response consist of? It was originally designed to protect us. Once we are under stress, our blood pressure, heart rate and breathing rate will increase. Blood will also be diverted from nonessential functions to more critical organs in the body. Hormones (chemicals from glands that travel through the bloodstream to affect distant sites) are released from the adrenal gland, such as adrenaline, as well as others, amplify this response and cause the release of energy in the form of sugar from the liver and fatty tissue.
In addition, long-term building projects in the body such as growth and tissue repair are stopped in the short term. Our sex hormones plummet, while our immune system is boosted. Our pain perception is also dulled and our mental acuity increases as does our short-term memory.
What controls this whole process is something uniquely mammalian which is our cerebral cortex aided by a very primitive area of our cortex which helps us respond in these moments of crisis called the limbic system. These two areas of higher brain function help control the lower brain and brain stem in our response to stress.
The brainstem is directly connected to most of the tissues in the body by what is called the autonomic nervous system (ANS). This ANS has two parts that control all the involuntary functions in the body such as breathing, the heart beating, digestion, liver and kidney function, etc. The parasympathetic side controls most of the resting and vegetative functions such as slowing your breathing, slowing your heart rate, lowering your blood pressure and digestion. The sympathetic side controls the stimulation of your body to respond to stress such as your pupils dilating, increase in heart rate, increase in blood pressure and diverting the blood from nonessential tissues or projects to those essential for the "fight or flight" response.
In the next article we will discuss what happens when this system is turned on too often for long periods of time. As suspected there are unintended consequences.
Charles Russo M.D., FACC, is Board certified in internal medicine and cardiovascular disease. He lives in Fort Lauderdale with his wife and 4 children and obtained his medical degree from New York Medical College with his Cardiology degree from the University of Miami and has advanced degrees in nuclear Cardiology and Lipidology (the study of blood fats).
