Stress is mental or physical tension brought about by internal or external pressures. The feeling of stress may be mild or severe and it can last a short time or over a longer period. Many events may cause stress. They range from everyday occurrences such as taking a test or driving through rush-hour traffic to more traumatic experiences such as the death of a loved one or a serious illness.
Stress may be a factor in causing disease. Researchers believe that stress disrupts the body's homeostasis or balanced state, which leads to a weakening of the body's immune system. Chronic (frequently occurring) stress can thus bring about serious illnesses.
People who experience severe traumas, such as soldiers during combat, may develop a condition called post-traumatic stress disorder (PTSD). This condition was called shell shock during World War I (1914–18) and battle fatigue during World War II (1939–45). Sufferers of PTSD experience depression, nightmares, feelings of guilt for having survived, and flashbacks to the traumatic events. They may be excessively sensitive to noise and may even become violent.
Until the twenty-first century, scientists believed humans and animals reacted to stress in a common manner, by preparing to do battle or to flee. This syndrome is known as "fight or flight." In 2000, however, a group of researchers issued a report asserting that females (both human and animal) often show a different reaction to stress. Instead of aggression and escape, their reaction is one of nurturing and seeking the support of others. The researchers believe this response, called "tend and befriend," is the result of either hormonal differences between the sexes or learning and cultural conditioning experienced long ago in our evolutionary history. When human were first evolving, the "tend-and-befriend" response would have reduced the risk to females and their offspring posed by predators, natural disasters, and other threats.
Some of the physical signs of stress are a dry mouth and throat; tight muscles in the neck, shoulders, and back; chronic neck and back problems; headaches; indigestion; tremors; muscle tics; insomnia; and fatigue. Emotional signs of stress include tension, anxiety, depression, and emotional exhaustion.
During stress, heart rate quickens, blood pressure increases, and the body releases the hormone adrenaline, which speeds up the body's metabolism. If the stress continues over a period of time and the body does not return to its normal balanced state, the immune system begins to weaken.
Adrenaline: Chemical released from the adrenal gland in response to stress, exercise, or strong emotions.
Atherosclerosis: Disease of the arteries in which fatty material accumulates on the inner walls of the arteries, obstructing the flow of blood.
Homeostasis: State of being in balance.
Post-traumatic stress disorder (PTSD): Condition developed as a response to traumatic events such as those experienced in combat.
Medical researchers have determined that chronic stress causes the accumulation of fat, starch, calcium, and other substances in the linings of the blood vessels. This can lead to atherosclerosis, a condition in which blood flow through the arteries is obstructed. This condition ultimately results in heart disease. Other diseases associated with stress are adult diabetes, ulcers, high blood pressure, asthma, migraine headaches, cancer, and the common cold. While both sexes can suffer greatly from stress, men seem to experience more stress-related illnesses like hypertension and alcohol and drug abuse.
Some psychiatrists and therapists treat patients suffering from stress with medications such as antianxiety or antidepressant drugs. Other therapists help patients develop coping strategies to reduce or eliminate stress from their lives. Some life-style changes are often recommended. These include adopting a healthy diet, quitting smoking, increasing exercise activity, developing relaxation techniques (such as deep breathing and meditation), and taking part in group discussions. Knowing the causes of stress and being able to talk about them are considered important for reducing or eliminating stress.