The Mind and the Body ②–The relationship between stress and health

MRI brain scans show that people who have been under the prolonged influence of stress hormones have a shrunken hippocampus. One probable implication is that stress, a process by which people perceive and respond to certain event called stressor, might lead to serious physical consequence. Although some research remains inconsistent, others show that psychological factors like stress induce or affect physical illness, such as coronary heart disease and the immune system related disease. The influence of stress on health can vary with characteristics of stressor, individual response specificity and personality, and type of illness, which operate simultaneously.

The evidence that psychological factors and biological factors intricately interact and affect human health might provide clues for delineating the relationship between the mind and the body. The so-called mind-body problem has been debated in terms of dualism and monism or materialism, idealism, and neutral monism since ancient Greek. Whichever side is taken, it is increasingly accepted that mind and body interplay as a whole and affect each other as research of stress-related illness illustrates. This holistic concept of mind and body has led to health psychology in which some research aims to prevent or relieve stress-related illness.

Accumulated studies have confirmed that stress activates the sympathetic nervous system, increasing heart rate, blood pressure, and respiration, redistributing blood-flow, and so on. The generalized sympathetic arousal activity alerts the body by triggering an outburst of stress hormones, such as epinephrine and norepinephrine. While rebuilding the energy supply depleted by sympathetic activity, the parasympathetic nervous system reverses these processes. According to research, when fluctuation of these two sub-autonomic nervous systems goes beyond a certain range, change in physiology can bring people psychological disorders, such as anxiety disorder, and/or physical consequences, such as coronary heart disease or hypertension. For example, when an individual is threatened by stress, one’s active sympathetic nervous system redistributes blood-flow to the muscles from internal organs, such as the liver which removes cholesterol and fat from the blood. Thus, the blood may contain excess cholesterol and fat that later get placed around the heart. Research of the relationship between personality and coronary heart disease implies that aggressive achievers, who are type “A” individuals in terms of Friedman and Rosenman, are readily affected by stress and are more likely to have heart attack. Although the general relationship is not conclusive, some research demonstrates that an individual’s negative traits like hostility and anger correlates with coronary heart disease.

Research in psychoneuroimmunology shows that stress can also lead an individual to be susceptible to disease related to the immune system. The immune system, which is the body’s defense mechanism against infectious disease and cancer, includes disease-fighting agents, such as lymphocytes and macrophage. Type “B” lymphocytes release antibodies that fight bacterial infections; type “T” lymphocytes attack cancer cells, viruses, and other foreign bodies. Another agent, the macrophage patrols the body, and identifies and ingests harmful invaders. The nervous and endocrine systems have an effect on the immune system through regulating the secretion of stress hormones. Stress triggers physical arousal, diverting energy from the immune system to the muscles and brain, which, in turn, suppresses or deactivates the disease-fighting agents. According to the research that tested medical students’ blood periodically, the immune cells’ activity and their secretions decrease during the exam, which refers as to naturalistic minor event or stressor. Some research shows that during a stressful period, people are more likely to get cold, and surgical wounds heal more slowly.

It is still an open conclusion that deterioration of the immune system by stress is linked to the progression of AIDS from HIV infection and of cancer. Nevertheless, stress-related illness research steadily shows that stress can affect people’s physical illness. From the cognitive perspective, when people appraise stressors as unpredictable and uncontrollable, people are more likely to be vulnerable to disease. Cognitive therapy attempts to alleviate stress by changing the coping process. Besides this, some research shows that social support for cancer patients, stress coping skill techniques, and exercise can promote health by managing stress.