BackgroundThe social and economic impact of dementia for the development of accessible and sustainable care for individuals with dementia (IwD). Physical exercise has been seen as a beneficial non-pharmacological therapy in the prevention and management of dementia, and possible benefits may not only impact on participants, but also indirectly on their caregivers. Thus, this quasi-experimental non-randomized study aimed to analyze the effects of an exercise intervention on functional capacity, behavioural and psychological symptoms in dementia (BPSD) and quality of life of institutionalized older adults with dementia, perceived by their formal caregivers.MethodsSixty-four institutionalized older adults (from both genders, aged 65–93 yrs. old), clinically diagnosed with dementia, were divided into two groups: control group (CG, continued with usual care, n = 26) and exercise group (EG, 6-month supervised multicomponent exercise intervention, n = 38). Nine caregivers (female, aged 28–47 yrs. old) from nine different nursing homes, reported about their distress related to BPSD and proxy-reported about participants’ functional capacity (Katz index), quality of life (QoL-AD), BPSD (NPI) before and after 6 months of an exercise intervention (aerobic, muscular resistance, flexibility and postural exercises).ResultsA two-way ANOVA, with repeated measures, revealed significant group and time interactions on Total Katz index and QoL-AD. The CG’s performance functional capacity and quality of life score worsen over time while in EG maintains these values after the exercise intervention. Moreover, formal caregiver’s distress triggered by apathy and disinhibition increased in CG while after 6 months of an exercise intervention no alterations were seen regarding these distress causes in EG. No significant main effects were observed for total NPI score or NPI distress.ConclusionsOverall results show that after the exercise intervention, IwD from the EG, was capable of preserving the functional capacity, quality of life and neuropsychiatric symptoms were attenuate, contributing to a lower load of distress for the caregivers.Trial registrationclinicaltrials.gov, NCT04095962. Retrospectively registered on 19 September 2019