July 24, 2026, 4:03 pm | Read time: 4 minutes
Regular physical activity benefits the brain. However, it may not only be about how much you move, but also how movement is distributed throughout the day. A large study involving more than 66,000 adults suggests that longer, continuous activity and fewer interruptions may be linked to a lower risk of dementia, depression, and anxiety disorders.
It’s Not Just the Amount of Exercise That Counts
People who engaged in longer, continuous bouts of physical activity and had a less interrupted movement pattern were less likely to develop dementia, depression, or anxiety disorders during the follow-up period. This correlation was observed regardless of the total amount of daily activity participants achieved.
The results were particularly pronounced for longer periods of moderate to vigorous physical activity (MVPA). Compared to those without such activity phases, the lowest observed risk of dementia was seen with about 13 minutes of continuous MVPA. For depression and anxiety disorders, the most favorable outcomes were around 36 minutes.
How the Study Was Conducted
Researchers from the City University of Hong Kong examined whether the structure of physical activity, in addition to the total amount, is significant for brain and mental health. They analyzed data from 66,483 participants in the UK Biobank. Participants wore a wrist activity sensor for a week between 2013 and 2015, which objectively recorded their movements. They were then followed up for an average of about 7.5 years.1
The focus was on two features: the duration of continuous movement phases and so-called activity fragmentation. The latter describes how often someone switches between activity and inactivity. Many short activity units with frequent interruptions are considered highly fragmented, while longer movement phases are less fragmented.
Additionally, the researchers analyzed MRI scans of the brain in more than 13,000 participants to investigate possible connections between movement patterns and brain structures.
Connections Between Movement and Brain Structure
During the follow-up period, 425 participants were diagnosed with dementia, 1,101 with depression, and 1,290 with anxiety. Longer phases of low-intensity physical activity were not statistically clearly associated with a reduced risk of depression.
Furthermore, the researchers found indications of connections with brain structure. Longer phases of moderate to vigorous physical activity (MVPA) were linked to a larger hippocampal volume, a brain region important for memory and learning. Less fragmented movement patterns were also associated with fewer changes in white matter, which is considered a sign of better brain health.
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What This Specifically Means
The findings suggest that not only the total amount of physical activity but also its distribution throughout the day is related to the risk of dementia, depression, and anxiety disorders. The relationships were particularly pronounced for longer, continuous phases of moderate to vigorous physical activity and for less fragmented movement patterns. These connections were even stronger in dementia cases among carriers of the genetic risk factor APOE4.
The numbers behind these findings are intriguing: Compared to people with highly fragmented movement patterns, those with the highest continuity had an 82 percent lower risk of dementia and about a 50 to 57 percent lower risk of depression and anxiety disorders.
Also interesting: These dementia risk factors are evident in people as young as 20
Study Context and Possible Limitations
The strengths of the study include the large number of participants, the objective measurement of physical activity via sensor, the long follow-up period of an average of 7.5 years, and the consideration of numerous potential influencing factors.
The authors note limitations, such as certain forms of exercise like strength training may not have been fully captured. Also, undetected early stages of dementia, depression, or anxiety disorders could have influenced movement behavior.
Moreover, the brain analyses do not allow conclusions about cause and effect, the study group consisted predominantly of white participants from the UK, and the assessment of increased susceptibility to depression and anxiety disorders was partly based on self-reports.
As this is an observational study, only associations, not causal protective effects of longer movement phases, can be demonstrated.