We know exercise reduces dementia risk. So does good sleep, social engagement, and healthy eating. But there's a catch: all of these take time. And time, according to a provocative commentary in The Lancet Healthy Longevity, is itself a social determinant of brain health that we've largely ignored.
Temporal Inequity
The authors introduce the concept of "temporal inequity" - the unequal distribution of discretionary time due to structural conditions shaping daily life. Some people have plenty of time for exercise, rest, and socializing. Others are squeezed by work demands, caregiving responsibilities, and economic pressures.
This inequality isn't just inconvenient. It may directly impact brain aging.
Time Poverty
"Time poverty" is a measurable manifestation of temporal inequity - having insufficient time for brain-healthy activities. The evidence for modifiable risk factors like physical activity, nutrition, and social engagement is strong. But adopting these behaviors requires time that many people simply don't have.
Performance-driven cultures and digital encroachment into personal time make this worse. When work emails follow you home and weekends evaporate into catch-up tasks, the time for brain health gets squeezed out.
Who Gets Time?
Time poverty disproportionately affects structurally disadvantaged populations. Lower-income workers often have less control over their schedules. Women typically bear more caregiving burdens. These inequalities compound other health disparities, potentially contributing to unequal dementia risk.
A Call for Temporal Justice
The authors argue for a paradigm shift: recognizing time as both a resource and a site of inequity in aging research. This means developing metrics for temporal inequity, studying how time-use patterns relate to brain health outcomes, and evaluating policies that could expand equitable access to time.
Whether through flexible work arrangements, better support for caregivers, or redesigned urban environments, addressing temporal inequity could be a novel approach to dementia prevention.
Reference: Röhr S, et al. (2025). Making time for brain health: recognising temporal inequity in dementia risk reduction. The Lancet Healthy Longevity. doi: 10.1016/j.lanhl.2025.100768 | PMID: 41101324
Disclaimer: The image accompanying this article is for illustrative purposes only and does not depict actual experimental results, data, or biological mechanisms.