Occupational stress is psychological stress related to one's job. Occupational stress refers to a chronic condition. Occupational stress can be managed by understanding what the stressful conditions at work are and taking steps to remediate those conditions. Occupational stress can occur when workers do not feel supported by supervisors or coworkers, feel as if they have little control over the work they perform, or find that their efforts on the job are incommensurate with the job's rewards. Occupational stress is a concern for both employees and employers because stressful job conditions are related to employees' emotional well-being, physical health, and job performance. A landmark study conducted by the World Health Organization and the International Labour Organization found that exposure to long working hours, which are theorized to operate through increased psycho-social occupational stress, is the occupational risk factor with the largest attributable burden of disease, according to these official estimates causing an estimated 745,000 workers to die from ischemic heart disease and stroke events in 2016. A number of disciplines within psychology are concerned with occupational stress including occupational health psychology, human factors and ergonomics, epidemiology, occupational medicine, sociology, industrial and organizational psychology, and industrial engineering. Psychological theories of worker stress A number of psychological theories at least partly explain the occurrence of occupational stress. The theories include the demand-control-support model, the effort-reward imbalance model, the person-environment fit model, job characteristics model, the diathesis stress model, and the job-demands resources model. Demand-control-support model The demand-control-support (DCS) model, originally the demand-control (DC) model, has been the most influential psychological theory in occupational stress research. The DC model advances the idea that the combination of low levels of work-related decision latitude (i.e., autonomy and control over the job) and high psychological workloads is harmful to the health of workers. High workloads and low levels of decision latitude either in combination or singly can lead to job strain, the term often used in the field of occupational health psychology to reflect poorer mental or physical health. The DC model has been extended to include work-related social isolation or lack of support from coworkers and supervisors to become the DCS model. Evidence indicates that high workload, low levels of decision latitude, and low levels of support either in combination or singly lead to poorer health. The combination of high workload, low levels of decision latitude, and low levels of support has also been termed