# Regular physical activity affects brain activities in old individuals: an observational study

## TL;DR

Regular physical activity in older adults is linked to changes in brain activity that reflect cognitive health, which can help guide treatment for dementia.

## Contribution

This study shows that brain activity measured by magnetoencephalography reflects the impact of physical activity on cognitive function in older individuals.

## Key findings

- Active individuals showed significant differences in three spectral parameters compared to nonactive individuals.
- The impact of physical activity on brain activity was comparable to large changes in cognitive test scores.
- Electrophysiological brain activity reflects both cognitive state and the influence of physical activity.

## Abstract

A healthy lifestyle, including regular physical activity, prevents cognitive decline and dementia. Evaluating the influence of regular physical activity on the brain is essential for properly assessing patients’ conditions and designing effective therapeutic strategies. We aimed to investigate whether and how electrophysiological brain activity reflects the influence of regular physical activity.

Clinical records from 327 patients who visited our outpatient department for dementia were analysed retrospectively. Patients were classified into two groups: ‘Active’ for those who engaged in regular physical activity and ‘Nonactive’ for patients who did not. Electrophysiological brain activity was recorded using magnetoencephalography and quantitatively evaluated using three spectral parameters: median frequency, individual alpha frequency, and Shannon’s spectral entropy. Cognitive state was assessed using three neuropsychological assessments: the Japanese version of Mini-Mental State Examination (MMSE-J), Frontal Assessment Battery (FAB-J), and Alzheimer’s Disease Assessment Scale-Cognitive section (ADAS-J cog). The effects of group (‘Active’ or ‘Nonactive’) on the spectral parameters were examined using an analysis of covariance with one of the neuropsychological assessments as a covariate. The size of contribution was quantified in the unit of neuropsychological assessments using a regression model. A main effect of group was observed for all three spectral parameters. The size of contribution was equivalent to approximate changes of 3–11 points in MMSE-J, 3–7 points in FAB-J, and 10–14 points in ADAS-J cog scores. The main limitations of our study are: (1) this study was conducted in a single site; (2) possibility of reverse causality; and (3) some potential confounding factors, such as genetic factors, were not considered.

Electrophysiological brain activity reflects the influence of regular physical activity as well as current cognitive states. Such insights are valuable for physicians to design effective therapeutic strategies and provide clinical advice to patients with cognitive impairment and dementia.