The ability to anticipate future events allows us to plan and exert control over our lives, but it may also contribute to stress-related increased risk for the diseases of aging, according to a study by University of California, San Francisco researchers. In a study of 50 women, about half of them caring for relatives with dementia, the psychologists found that those most threatened by the anticipation of stressful tasks in the laboratory and through public speaking and solving math problems, looked older at the cellular level. The researchers assessed cellular age by measuring telomeres, which are the protective caps on the ends of chromosomes. Short telomeres index older cellular age and are associated with increased risk for a host of chronic diseases of aging, including cancer, heart disease and stroke.