Health psychology is a relatively new field in psychology; health psychologists attempt to prevent health problems by helping individuals cope with stress and by helping to promote healthy lifestyles. Stress is any event that strains or exceeds an individual's capacity to cope. Among the major sources of stress in our lives are frustration, the inability to satisfy a motive, and conflict, the result of two or more incompatible motives. Four types of conflict are (1) approach-approach conflict, (2) avoidance-avoidance conflict, (3) approach-avoidance conflict, and (4) multiple approach-avoidance conflict. Pressure, an additional source of stress, arises from the threat of negative events. Another source of stress comes from the positive and the negative changes that occur in our lives. There is also growing evidence that environmental stresses, such as heat, cold, and air pollution, can be stressful. Reactions to stress are very similar whether the stress is physical or psychological. Selye has identified a consistent pattern of bodily responses to stress called the general adaptation syndrome. This syndrome consists of three stages: the alarm stage, the resistance stage, and the exhaustion stage. Stress affects our emotions, our immune system, our motivations, and our cognition.

Events are generally less stressful when we have had some prior experience with them, when they are predictable, when we have some control over them, and when we receive social support. The characteristics of individuals also affect their reactions to stress. Cognitive factors are important in our reaction to stress. Sensitizers and repressors react differently to stress.

Much research has been conducted on the Type A personality and its link to heart disease. Hostility seems to be the dangerous component of type A behavior.

Our efforts to cope with stress can be either effective or ineffective. Effective methods of coping with stress include removing the source of stress, cognitive coping, and managing our reactions to stress. Ineffective coping strategies include withdrawal, aggression, self-medication, and the use of defense mechanisms.

A major goal of health psychology is to prevent health problems. Relaxation training is one technique used to achieve this goal. Health psychologists also seek to reduce health risks by helping individuals exercise properly, eat a healthy diet, and properly follow their medical treatments.

Some health psychologists seek to treat health problems. Psychologists have become involved with the AIDS epidemic through efforts to understand and control behavioral aspects of the transmission of AIDS and through efforts to slow the progress of the disease in those who are infected.