The purpose of this study was to provide basic data for nursing programs to reduce fatigue among middle-aged adults by looking at age group differences.

The study used a secondary analysis design and participants were 315 middle-aged adults. The data was analyzed using χ²-test, ANOVA, Pearson's correlation coefficient analysis, and stepwise multiple regression.

The findings revealed significant age group differences in socio-demographic variables for educational level, job, religion, economic status, consumption of cigarettes, experience with disease, satisfaction with spouse and children, and number of children. Scores of fatigue showed a significant difference between age groups. The factors influencing fatigue for subjects in their thirties were depression, level of education and self-efficacy. For those in their forties, factors were stress, depression, and self-efficacy. For those in their fifties, the factor was stress.

For people in their thirties, school education or lifelong learning programs are needed to reduce fatigue. A disease prevention program and a family support program for people in their forties and fifties. Nurses need to provide customized nursing programs related to depression, stress and self-efficacy to reduce fatigue among middle-aged adults based on age groups.