ObjectivesFatigue is highly prevalent among older adults with multimorbidity. As the World Health Organization advocates for strategies that improve the functional status of this aged cohort, this study examined the effects of a low-impact moderate-intensity exercise program on their fatigue levels and related functional health outcomes. Methods and MaterialsA multi-site clinical trial randomized 124 community-dwelling older adults with multimorbidity [mean age: 78.1 years (SD: 7.0); female: 83.8%] to a low-impact exercise program (intervention) group or a health education (control) group. The exercise program was designed to address fatigue-associated low energy levels, and consisted of thrice-weekly low-impact stepping exercises that were progressively increased from low intensity to moderate intensity over a 12-week period, using group-based practice to encourage engagement. The Multidimensional Fatigue Inventory, FRAIL Scale, International Physical Activity Questionnaire, the two-minute walking test, and Profile of Mood States (short-from) were administered at baseline, post-intervention, and 12 weeks thereafter. ResultsGeneralized estimating equation showed that the intervention group reported greater decreases in fatigue and frailty, and greater improvements in physical activity level, exercise tolerance, and mood status than the control group. The positive effects of the intervention on most of these outcomes were sustained over the two post-test endpoints. Discussion and implicationsThe low-impact stepping-based moderate-intensity exercise program is effective to improve fatigue and functional outcomes in older adults with multimorbidity. As it can be challenging to engage the fatigued older adults in exercise training, this study adds insights to inform community-based care approach for multimorbidity management.