Does Emotional Stress Affect the Body?
I recently saw a patient of mine after a hospitalization for stomach ulcers. He'd noticed a correlation between the ulcers and the job-related stress he'd been enduring over the last few months. When he asked me if I thought there was a relation, I wavered a bit about making the link between stress and his ulcers.
Do we mistakenly blame stress for our maladies, or does it legitimately take its toll on our bodies?
The Physiological Toll of Emotional Stress
Our nervous system is consists of different wiring systems. One of these is called the sympathetic nervous system (SNS). This set of nerves and hormonal signals essentially regulates our "fight-or-flight" response, an excited state that puts our body on high alert courtesy of the hormone epinephrine (aka adrenaline). When the SNS is activated, our pupils dilate, blood pressure rises, heart rate increases, bowels slow, stomach produces acid, and breathing increases - all of this in anticipation of, you guessed it... a fight or flight situation.
Emotionally, this response enhances the feelings of being "on edge." We clench our muscles and our responses to physical stimuli are heightened. Emotional stress also decreases quality sleep by prolonging the time for the body to slip into the deep, restorative REM state. Chronic activation of the SNS also elevates levels of a chemical messenger called cortisol. Cortisol increases blood sugar, shunts energy to fatty stores, hardens arteries, and is believed to weaken the immune system.
Myths and Facts About Stress and Its Effect on the Body
It's time to take a look at a few maladies that have been linked to stress to determine whether or not they are actually related to stress.
Heart Disease: Fact
Those fight-or-flight hormones definitely make the heart work harder, increasing the pumping against higher blood pressure. Chronic cortisol elevations cause hardening of the arteries. Studies have shown increases in heart disease among "type A" personalities.
There has been speculation that cortisol weakens the immune system and down regulates an important chemical messenger called tumor necrosis factor (TNF). TNF acts as a watchdog in keeping our cells safe from cancer, monitoring mistakes in the duplication of our DNA in cell turnover. And while it seems that stressed people get cancer more often, no definitive link has been proven.
Susceptibility to Infection: Unknown
How many times have we felt that we were burning the candle at both ends and wound up with a cold? As stated above, cortisol is thought to have a negative affect on the immune system. When considering the immune system more concretely, it is important to note that physical stressors, such as injuries, lack of sleep, or poor nutrition have been scientifically proven to be causal in the susceptibility to infection. Emotional stress, however, remains mere speculation at this point.
Looking at American Presidents and other public officials after a term or two in office would lead to the conclusion that emotional stress causes wrinkles, but correlation does not always equal causation.
Physical stressors on the body, such as lack of sleep, poor nutrition, and volunatry pollutants such as cigarettes or crystal meth have been scientifically shown to break down collagen in the skin. While emotional stress often coincides with these physical stressors, it, along with activation of the sympathetic nervous system, has not been shown to cause wrinkles.
Grey hair: Myth
Premature greying is basically in the same boat as wrinkles. Metabolic disorders, namely low thyroid levels, are associated with greying. A genetic predisposition is the most common factor, and emotional stress has not been shown to cause hair to turn grey before the genetics kick in. In other words, look to your parents and not the stress in your life.
Both physical, genetic, and emotional factors have been shown to cause baldness. Genetics are associated with pattern baldness (temples and crown). Patchy baldness has been associated with fungal infection and a condition called alopecia areata, of which, emotional stress is a know cause. More diffuse balding is commonly caused by a condition called telogen effluvium. Malnutrition, chronic disease, and emotional stress are all known causes.
Obesity has a number of causes, most of which are behavioral. Chronic emotional stress increases cortisol levels, which keeps energy in fatty stores. Stress also leads to poor sleep, which often leads to increased carbohydrate intake as a means to gain energy. That energy, in the absence of energy expenditure through exercise, gets pushed into fatty stores. Lastly, emotional stress often leads to stress eating, which then leads to obesity.
Mental illness: Fact
Chronic emotional stress strains the neurohormones that modulate mood (serotonin, dopamine, and adrenaline) and can lead to depression and/or anxiety. In regards to more chronic mental illness such as schizophrenia, no definitive link has been found.
Homeless populations have been studied extensively due to the high degree of schizophrenia and other psychoses. The "downward drift hypotheses" is concerned with whether homelessness was due to mental illness or whether the mental illness was due to the stressors of homelessness. No definitive answer has been accepted.
Aside from this, however, one can say that emotional stress can lead to mental illness.
While bowel function in general slows with activation of the sympathetic nervous system, the stomach produces excess acid (possibly due to underlying emotional stress). When there is no food in the stomach to buffer the acid and trigger movement into the intestines, it can damage the lining of the stomach. This can lead to ulcers, areas of inflammation and breakdown in the wall of the stomach.
I often tell patients that stress serves as a magnifying glass for any problems we might have. For some issues, stress intensifies our struggle, but it is causal for others. And while we are tempted to blame some issues on stress, science cannot prove an association in all of these cases.
We'll keep looking for possible relationships between emotional stressors and physical responses, but in the meantime, please don't tell my kids that they're not the reason for my greying hair.