Worldwide, more than 55 million individuals have Alzheimer's disease and related dementias (ADRD).1 In 2023, ADRD is the seventh leading cause of death in the U.S. and an estimated 6.7 million U.S. older adults are living with ADRD, accounting for about 11 % of individuals aged 65 years or older.2 The growing prevalence of these neurodegenerative disorders is a problem for patients as well as their uncompensated informal caregivers (e.g., family members and/or close friends). Economically, the value of uncompensated care provided by informal caregivers was estimated to be $339.5 billion in the U.S. in 2022.2 Couples in romantic relationships often take the role of informal caregivers. In the U.S., more than 60 % of informal caregivers who live with people with ADRD are romantic partners, including spouses (i.e., romantic care partners), increasing the risk for romantic care partners to experience declines in their own health.2,3

Given that there is no definitive cure for ADRD, prevention is a priority for both patients and informal caregivers. Mild cognitive impairment (MCI), for which the main characteristics are cognitive decline but with intact capacity for activities of daily living, is considered a prodromal phase of ADRD.4 Approximately 30 to 50 % of individuals with MCI are reported to be diagnosed with ADRD over 5 to 10 years.5,6 Over one-third of the informal caregivers of these individuals report experiencing clinically significant strain due to patients’ cognitive and neuropsychiatric symptoms that can worsen over time.7,8

The beneficial effects of physical activity (PA), including aerobic and muscle-strengthening activities, on cognitive health and physical and psychological health for older adults with cognitive decline (i.e., MCI or ADRD) and/or their informal caregivers are well documented.9, 10, 11, 12 These benefits include improved memory and executive function, aerobic fitness, strength, balance, health-related quality of life, and caregiver well-being and decreased depressive symptoms and caregiver burden. The PA guidelines for adults in the U.S. emphasize moderate-to-vigorous aerobic activities (MVPA ≥ 150 minutes/week) and muscle-strengthening activities (≥ 2 sessions/week).13 However, as few as 17 % of older adults in the U.S. aged 65 years or over meet the guidelines for both MVPA and muscle-strengthening activities, and this rate tends to decrease further among older adults with MCI.14,15 In addition, romantic care partners for older adults with MCI are less likely to engage in PA because their new caregiving responsibilities disrupt their established lifestyles by providing more hours of care compared with other types of informal caregivers such as adult children and friends.16,17 However, there are limited strategies for promoting PA among community-dwelling older adults with MCI and their romantic care partners. Given the benefits of PA, increasing PA could improve physical and mental well-being, potentially delaying the onset of ADRD and decreasing onerous aspects of caregiving over time.

Partner support is helpful for PA among older couples as social circles tend to decrease in older age.18 Mutual support between couples was most evident when engaging in PA together.19,20 Under this hypothesis, the purposes of our proof-of-concept study were to (1) evaluate the feasibility of the dyadic approach to regular PA based on the guidelines for U.S. adults, (2) identify the patterns of physical health (e.g., aerobic fitness, lower body strength, and functional balance for older adults with MCI), psychological health (e.g., depressive symptoms for older adults with MCI and romantic care partners as well as caregiver burden and well-being for romantic care partners), and/or cognition (e.g., episodic memory and executive function for older adults with MCI) over time, and (3) explore study experiences among older adults with MCI and their romantic care partners.