Causes of stress are known as stressors. Stressors can be physical or emotional, internally or externally generated. Stressors can be events, situations, people or demands the individual perceives to be the source of stress. The most common stressor is change, such as loss of a loved one, career change, illness or injury, and lifestyle changes. Stressors also vary amongst people; children, teens and adults are all capable of experiencing stress yet, there are some stressors that are specific to the age or type of person.