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).

Inclusion criteria:

1. males and females aged 60 until 85
2. living in the community,
3. confirmed diagnosis of MCI
4. able to walk without assistance for at least two minutes,
5. able to participate in exercise intervention screened by a physician based on ACSM guidelines

Exclusion criteria:

1. uncertain diagnosis of MCI,
2. did not screen for ability to participate in exercise intervention,
3. presence of other neurological, psychiatric, or cognitive impairment disorders,
4. seriously ill, presence of Hepatitis B or C, cancer, and patients on immunosuppressant drugs,
5. type 2 diabetes mellitus,
6. uncontrolled hypertension or hypotension (systolic blood pressure >160 mm Hg and/or diastolic blood pressure >100 mm Hg at rest),
7. unstable cardiac, renal, lung, liver, or other severe chronic disease,
8. history of myocardial infarction and/or stroke within previous year,
9. vision/hearing disorder,
10. musculoskeletal disorders that affect physical function such as osteoporosis, severe knee osteoarthritis, and degenerative spinal condition,
11. presence of any major psychiatric disorder (a clinical diagnosis of major depressive disorder, bipolar or schizophrenia)
12. history of vitamin B12 deficiency or hypothyroidism (stable treatment for at least 3 months is allowed)
13. serious or non-healing wound, ulcer, or bone fracture

Data confidentiality Human subjects participation in this study will involve the collection, use and disclosure of data / health information in an individually identifiable form (or "Personal Data"). "Personal Data" means data about the participants, which makes them identifiable from (i) such data, and/or from (ii) other information which we have or likely have access to. This includes written, visual, video, audio data/recordings, medical conditions, medications, investigations and treatment history.

Personal Data and data collected for this study will be kept confidential and stored for a minimum of 10 years in a secure environment within NTU. Access will be restricted to the Principal Investigator, study team members, and School Administrators. The records, to the extent of the applicable laws and regulations, will not be made publicly available, in accordance with the NTU Privacy Statement.