8-week exercise trial in older adults: greater neurite density index increase than active control
In this secondary analysis of a randomized trial with 66 older adults, an 8-week remotely delivered multicomponent exercise program produced a greater increase in an MRI-based neurite density index across white matter tracts than an active control; the orientation dispersion index showed no such effect. [1]
Automatic summary · not editorially reviewed
The key findings
The secondary analysis of a randomized trial included 66 older adults with diffusion MRI data, randomized to a remotely delivered 8-week multicomponent exercise program (n = 34) or an active control (n = 32). [1]
A significant timepoint-by-group interaction for neurite density (p = 0.003) indicated a greater increase in the exercise group, confirmed in Bayesian analyses for 22 white matter tracts; the orientation dispersion index showed no significant interaction (p = 0.785). [1]
The standardized composite VO2max score rose from before to after the intervention within the exercise group, but the timepoint-by-group interaction was not significant (p = 0.079). [1]
The source at a glance
- Study type / format
- Secondary analysis of a randomized controlled trial (abstract).
- Population / context
- Older adults with available diffusion MRI data (n = 66; age 66.4 ± 3.6 years; 43 females).
- Summary based on
- Study abstract
- Publication status
- Preprint · peer-review status not confirmed
- Original publication
- September 4, 2026
Exercise versus active control in 66 older adults
The abstract describes a secondary analysis of a randomized controlled trial. It included 66 participants with available diffusion MRI data (age 66.4 ± 3.6 years; 43 females). They were randomized to a multicomponent exercise program (PAG, n = 34) or an active control intervention (CON, n = 32). The program was delivered remotely over 8 weeks. The authors note that cross-sectional studies suggest associations between exercise and white matter in older adults, but randomized trial evidence is scarce.
Supporting source [1]
Neurite density rose more with exercise; orientation index unchanged
The researchers measured two MRI-based indices of white matter microstructure: neurite density (NDI) and orientation dispersion (ODI). For NDI, they report a significant interaction between timepoint and group (p = 0.003), indicating a greater increase in the exercise group; Bayesian analyses confirmed this for 22 white matter tracts. For ODI, this interaction was not significant (p = 0.785). The standardized composite VO2max score increased from before to after the intervention within the exercise group, but the timepoint-by-group interaction was not significant (p = 0.079). Across all participants, pre-to-post changes in mean NDI correlated positively with changes in VO2max, without a difference between groups.
Supporting source [1]
Abstract-only scope of a secondary imaging analysis
These findings come from the abstract only; the full text was not reviewed. The analysis is a secondary analysis of trial data and covers only participants with available diffusion MRI data (n = 66), so it does not describe the full trial population. The reported outcomes are MRI-based microstructure indices, not clinical or cognitive outcomes. The authors describe the results as indicating that white matter microstructure remains responsive to short-term multicomponent exercise in older adults; the abstract does not establish causes of aging-related white matter change or long-term effects.
Supporting source [1]
How to interpret this
Abstract only; the full text was not reviewed. This is a secondary analysis restricted to participants with available diffusion MRI data (n = 66), and the outcomes are MRI-based microstructure indices rather than clinical or cognitive measures.
Based on the study abstract; the full paper, tables and supplementary data were not reviewed.
Source & supporting passages
Ruiz-Rizzo AL, Schrenk SJ, Brodoehl S, Frahm C, Gaser C, Herbsleb M, Puta C, Witte OW, Finke K. · europepmc.org · September 4, 2026