Optimising Exercise to Improve Physical and Cognitive Frailty in Mild Cognitive Impairment

This investigational research aims to understand the mechanism of delaying the progression of dementia through different types of exercise. Exercise plays a protective role by attenuating the progression of cognitive impairments in mild cognitive impairment (MCI), an early and reversible stage of dementia. However, how different types of exercise induce changes in physical frailty and cognitive function is understudied. The participants will be randomized to receive an exercise intervention program (cycling or strength training) for 12 weeks or a control group. The participants will be asked to perform certain cognitive and physical assessments at the start of the study, at the end of 12 weeks of exercise intervention, and 4 weeks after the end of the intervention. Below is the list of the assessments: * Patient Health Questionnaire-9 (PHQ-9) * World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0-12) * Self-report on sociodemographic characteristics, ethnicity, socioeconomic status, educational level, smoking status, alcohol intake, comorbidities, chronic medications, social activities, history of falls * body height, weight and fat percentage, heart rate, blood pressure, Dual-Energy X-Ray Absorptiometry (DEXA) scan: measurements to evaluate overall physical characteristics * handgrip strength: to evaluate musculoskeletal function * Stroop test: to evaluate information processing speed and executive cognitive control * n-back task: to evaluate working memory and executive function * Timed Up and Go (TUG) test: to measure balance * single-task gait: to measure walking ability * double-task gait: to measure walking stability and attention During Stroop test, n-back task, Timed Up and Go (TUG) test, single-task gait and double-task gait, the participants will be equipped with a mobile functional near-infrared spectroscopy (fNIRS) device over their forehead. This device is used to detect changes in blood flow in the front area of the brain. Their participation will last approximately 18 weeks (2 weeks of familiarization and assessment, 12 weeks of exercise intervention, and 4 weeks of follow-up).