Cognitive decline and sleep concerns are significant health issues among older adults. Nonpharmacological treatments to address these concerns are needed, particularly for older adults who are more likely to be prescribed multiple medications and experience adverse effects of additional drugs. The aim of the current qualitative study was to understand and document the experiences of older adults with subjective memory decline participating in prolonged nightly fasting (PNF) intervention.

This single-group pilot study was conducted as a fully remote, 8-week, pre/postintervention. Postintervention, 16 participants (≥65 years) participated in semistructured qualitative exit interviews about their experiences with the PNF intervention. Interviews lasted approximately 20–30 minutes, were conducted by trained study staff, and then analyzed by the team to understand relevant themes.

Two major themes that emerged from the data were engagement with and perceived effects of the PNF intervention. Within these two themes, nine subthemes emerged: accountability; use of days off; feasibility; intervention tools; behavioral strategies; timing/routine; awareness; self-efficacy; and perceived health-related outcomes. Overall, interviews suggested strong engagement with the PNF intervention as well as a number of positive perceived effects of the intervention.

These findings contribute to a broad field of intermittent fasting by exploring and understanding the direct experiences of older adults participating in PNF. Some participants identified challenges of participation, yet this qualitative approach can guide future PNF implementation with older adults. Notably, responses support the quantitative data suggesting that PNF is a feasible and acceptable intervention for older adults.

Older age significantly increases risk for cognitive decline. A growing number of older adults (≥ 65 years) experience cognitive decline that compromises immediate and/or long-term health. Interventions to mitigate cognitive decline are greatly needed. Intermittent fasting aligned with innate circadian rhythms is associated with health benefits and improved circadian rhythms; here, we explore impacts on cognition and cardiometabolic outcomes.

We conducted a single-group, pre-/post-pilot study to explore an 8-week prolonged nightly fasting intervention (14 h fasting/night) among adults 65+ years with self-reported memory decline. We explored changes in cognitive function, insomnia, and cardiometabolic risk factors. Intervention engagement/adherence were assessed. The intervention was delivered fully remotely; participants completed their fasting protocol at home and were not required to come into the lab.

In total, 20 individuals signed consent and 18 participants completed the study. Participants were mean age 69.7 years, non-Hispanic White (89%), predominantly female (95%), married (50%), and employed (65%). Paired t-tests indicated an increase in cognitive function (Memory and Attention Phone Screener) (p = 0.02) with a medium effect size (Cohen’s d = 0.58) and a decrease in insomnia (Insomnia Severity Index) (p = 0.04) with a medium effect size (Cohen’s d = 0.52). Changes in BMI or diet quality were not observed. Engagement (66%–77%) and adherence (70%–100%) were high.

These pilot findings suggest that prolonged nightly fasting, targeted to align food intake with circadian rhythms, may improve cognitive function and sleep among older adults. Fully powered, randomized controlled trials to test the efficacy of this non-pharmacological, low cost-to-burden ratio intervention are needed.