What are the Negative effects of Stress?
In prehistoric times, the physical changes in response to stress were an essential adaptation for meeting natural threats. Even in the modern world, the stress response can be an asset for raising levels of performance during critical events such as a sports activity, an important meeting, or in situations of actual danger or crisis. If stress becomes persistent and low-level, however, all parts of the body’s stress apparatus (the brain, heart, lungs, vessels, and muscles) become chronically over- or under-activated. This may produce physical or psychologic damage over time. Acute stress can also be harmful in certain situations.

Stress-related conditions that are most likely to produce negative physical effects include:

 
• An accumulation of persistent stressful situations, particularly those that a person cannot easily control (for example, high-pressured work plus an unhappy relationship).  
• Persistent stress following a severe acute response to a traumatic event (such as an automobile accident).  
• An inefficient or insufficient relaxation response.  
• Acute stress in people with serious illness, such as Heart disease.

Psychologic Effects of Stress
Studies suggest that the inability to adapt to stress is associated with the onset of Depression or anxiety. In one study, two-thirds of subjects who experienced a stressful situation had nearly six times the risk of developing Depression within that month. Some evidence suggests that repeated release of stress hormone produces hyperactivity in the hypothalamus-pituitary-adrenal axis and disrupts normal levels of serotonin, the nerve chemical that is critical for feelings of well-being. Certainly, on a more obvious level, stress diminishes the quality of life by reducing feelings of pleasure and accomplishment, and relationships are often threatened.

Heart disease
Mental stress is as major a trigger for angina as physical stress. Incidents of acute stress have been associated with a higher risk for serious cardiac events, such as heart rhythm abnormalities and Heart Attacks, and even death from such events in people with Heart disease.

Stress activates the sympathetic nervous system (the automatic part of the nervous system that affects many organs, including the heart). Such actions and others may negatively affect the heart in several ways:

 
• Sudden stress increases the pumping action and rate of the heart and causes the arteries to constrict, thereby posing a risk for blocking blood flow to the heart.  
• Emotional effects of stress alter the heart rhythms and pose a risk for serious arrythmias in people with existing heart rhythm disturbances.  
• Stress causes blood to become stickier (possibly in preparation of potential injury), increasing the likelihood of an artery-clogging blood clot.  
• Stress may signal the body to release fat into the bloodstream, raising blood-cholesterol levels, at least temporarily.  
• In women, chronic stress may reduce estrogen levels, which are important for cardiac health.  
• Stressful events may cause men and women who have relatively low levels of the neurotransmitter serotonin (and therefore a higher risk for Depression or anger) to produce more of certain immune system proteins (called cytokines), which in high amounts cause inflammation and damage to cells, including possibly heart cells.  
• Recent evidence confirms the association between stress and hypertension (high blood pressure). People who regularly experience sudden increases in blood pressure caused by mental stress may, over time, develop injuries in the inner lining of their blood vessels. In one 20-year study, for example, men who periodically measured highest on the stress scale were twice as likely to have high blood pressure as those with normal stress. The effects of stress on blood pressure in women were less clear.

More research is needed to confirm the actual harm of stress on the heart. For example, one study of people who work under demanding conditions suggested that Heart disease, including high blood pressure, attributed to work stress may simply be due to the way people cope with the stress. People who are trying to deal with stress often resort to unhealthy habits including high-fat and high-salt diets, tobacco use, alcohol abuse, and a sedentary lifestyle. In one study, men were more apt to use alcohol or eat less healthily in response to stress, while women tended to have healthier ways of coping.

Stroke
One survey revealed that men who had a more intense response to stressful situations, such as waiting in line or problems at work, were more likely to have Strokes than those who did not report such distress. In some people prolonged or frequent mental stress causes an exaggerated increase in blood pressure. In fact, a 2001 study has linked for the first time a higher risk for Stroke in adult Caucasian men and elevated blood pressure during times of stress.

Susceptibility to Infections
Chronic stress appears to blunt the immune response and increase the risk for infections and may even impair a person’s response to immunizations. A number of studies have shown that subjects under chronic stress have low white blood cell counts and are vulnerable to colds. And once any person catches a cold or flu, stress can exacerbate symptoms. People who harbor herpes or HIV viruses may be more susceptible to viral activation following exposure to stress. Even more serious, some research has found that HIV-infected men with high stress levels progress more rapidly to AIDS when compared to those with lower stress levels. (In some studies, stressful events most linked with a higher incidence of infections were interpersonal conflicts, such as those at work or in a marriage.)

Immune Disorders
The contradictory effects of stress on the immune system can have mixed effects on autoimmune diseases (which are those that are caused by inflammation and damage from immune attacks on the body). For example,  Eczema, lupus, and Rheumatoid Arthritis may demonstrate changes ranging from improvement to deterioration in response to stress. A 2001 study reported that short-term stress appears to have no negative effect on multiple sclerosis, but chronic stress is a major risk factor for flare-ups.

Cancer
Current evidence does not support the idea that stress causes cancer. Nevertheless, some animal studies suggest that lack of control over stress (not simply stress itself) had negative effects on immune function and contributed to tumor growth. And, two small studies on Melanoma and Breast cancer patients reported improved survival with therapies that offered emotional support. Other research has not detected similar survival benefits, but support groups still have great value in reducing stress in patients with terminal cancer.

Gastrointestinal Problems
The brain and the intestine are strongly related and mediated by many of the same hormones and nervous system. (Indeed, some research suggests that the gut itself has features of a primitive brain.) It is not surprising then that prolonged stress can disrupt the digestive system, irritating the large intestine and causing Diarrhea, Constipation, cramping, and bloating. Excessive production of digestive acids in the stomach may cause a painful burning.

Irritable Bowel Syndrome. Irritable bowel syndrome (or spastic colon) is strongly related to stress. With this condition, the large intestine becomes irritated, and its muscular contractions are spastic rather than smooth and wave like. The abdomen is bloated and the patient experiences cramping and alternating periods of Constipation and diarrhea. Sleep disturbances due to stress can further exacerbate irritable bowel syndrome.

Peptic Ulcers. It is now well established that most peptic ulcers are either caused by the H. pylori bacteria or by the use of nonsteroidal anti-inflammatory (NSAID) medications (such as aspirin and ibuprofen). Nevertheless, studies still suggest that stress may predispose someone to ulcers or sustain existing ulcers. Some experts, in fact, estimate that social and psychologic factors play some contributing role in 30% to 60% of peptic ulcer cases, whether they are caused by H. pylori or NSAIDs. In any case, some experts believe that the anecdotal relationship between stress and ulcers is so strong that attention to psychological factors is still warranted.

Inflammatory bowel disease. Although stress is not a cause of inflammatory bowel disease (Crohn’s Disease or Ulcerative colitis), there are reports of an association between stress and symptom flare-ups. One study, for example, found that while short term (past month) stress did not significantly exacerbate Ulcerative colitis symptoms, long term perceived stress tripled the rate of flare-ups compared to patients who did not report feelings of stress.

Eating Problems
Stress can have varying effects on eating problems and weight.