Objective: To investigate the effect of functional task exercise on everyday problem-solving ability and functional status in older adults with mild cognitive impairment compared to single exercise or cognitive training and no treatment control.

Design: A single-blind, four-arm randomised controlled trial.

Setting: Out-patient clinic and community centre.

Participants: Older adults with mild cognitive impairment aged ≥60 living in community.

Methods: Participants (N = 145) were randomised to 8-week functional task exercise (N = 34), cognitive training (N = 38), exercise training (N = 37), or wait-list control (N = 36) group. Outcomes measures: Neurobehavioral Cognitive Status Examination, Category Verbal Fluency Test, Trail Making Test, Problems in Everyday Living Test, Activities of Daily Living Questionnaire, Instrumental Activities of Daily Living Scale; Chair stand test, Berg Balance Scale, and Short Form-12 Health Survey were conducted at baseline, post-intervention and 5-months follow-up.

Results: Post-intervention results of ANCOVA revealed cognitive training improved everyday problem-solving (P = 0.012) and exercise training improved functional status (P = 0.003) compared to wait-list control. Functional task exercise group demonstrated highest improvement compared to cognitive training, exercise training and wait-list control groups in executive function (P range = 0.003-0.018); everyday problem-solving (P < 0.001); functional status (P range = <.001-0.002); and physical performance (P = 0.008) at post-intervention, with all remained significant at 5-month follow-up, and further significant improvement in mental well-being (P = 0.043).

Conclusions: Functional task exercise could be an effective intervention to improve everyday problem-solving ability and functional status in older adults with mild cognitive impairment. The findings support combining cognitive and exercise intervention may give additive and even synergistic effects.