Scientists Say Time Matters As Much as Diet and Exercise for Your Brain

Time may be a key missing factor in dementia prevention, according to new research from UNSW Sydney’s Centre for Healthy Brain Aging (CHeBA).

New research suggests that time – or the lack of it – may be the missing link in effective dementia prevention.

The research, published in The Lancet Healthy Longevity, identifies time as an often overlooked social determinant of brain health, potentially as influential as education and income. The authors propose that “temporal inequity” – the uneven distribution of time among different groups in society – may seriously hinder people’s ability to lower their dementia risk.

Lead author and social determinants of health expert Associate Professor Susanne Röhr explained that although lifestyle habits such as adequate sleep, regular physical activity, good nutrition and social interaction are known to support brain health, each of these behaviors depends on one essential resource: time.

“Up to 45% of dementia cases worldwide could be prevented if modifiable risk factors were eliminated,” Assoc. Prof. Röhr said.

“However, many people simply don’t have the discretionary time to exercise, rest properly, eat healthily or stay socially connected. This lack of time – what we call “time poverty” – is a hidden barrier to dementia risk reduction.”

Structural causes of time poverty

The study emphasizes that structural factors such as long work hours, caregiving obligations, digital overload, and socioeconomic disadvantage contribute to “time poverty,” a burden that falls most heavily on already vulnerable populations. These pressures reinforce existing health disparities and reduce access to brain-supportive behaviors.

CHeBA Co-Director and co-author Professor Perminder Sachdev said that recognizing time as a social determinant of health requires a fundamental shift in how dementia prevention is approached.

“Brain health policy and research have focused heavily on individual behavior change,” Prof. Sachdev said.

“But unless people are given the temporal resources to act on these recommendations, we risk leaving behind those who need it most. Just as governments act on income inequality, we need to act on temporal inequity.”

Policy changes to advance temporal justice

The researchers call for policy and workplace reforms to support “temporal justice” which are measures that protect and redistribute time so that everyone can access the opportunity for brain health. Examples include flexible working arrangements, rights to disconnect, affordable childcare, investment in public transport, and urban planning that reduces commuting times.

Co-author Associate Professor Simone Reppermund said future research must also capture how much time is realistically needed for brain care.

“Our evidence suggests that at least 10 hours per day are required just for essential brain health activities such as sleep, meals, physical activity, and social interaction,” Assoc. Prof. Reppermund said.

“For many, especially those in disadvantaged or caregiving roles, this simply isn’t achievable under current conditions. Addressing time poverty is therefore essential if we are serious about preventing dementia.”

The authors argue that time must be recognized as both a resource and a site of inequity, urging governments, researchers, and communities to integrate temporal justice into dementia prevention strategies.

Reference: “Making time for brain health: recognizing temporal inequity in dementia risk reduction” by Susanne Röhr, Simone Reppermund, Annabel Matison, Suraj Samtani and Perminder S Sachdev, 13 October 2025, The Lancet Healthy Longevity.
DOI: 10.1016/j.lanhl.2025.100768

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