Effects of fitness and sedentarism on a biomarker of early AD progression

Background Given the lack of an effective treatment for Alzheimer’s Disease (AD), research on factors that might prevent it or delay its symptoms is needed. Physical activity (PA) stands as a means for favourably altering cognitive performance and neuropathologic processes and has been identified as a relevant and easily modifiable lifestyle factor against AD progression. This study thrives to understand the effects of both cardiorespiratory fitness (CRF) and sedentary behaviours (SB) in adult controls through the assessment of magnetoencephalography (MEG). Method 30 healthy adults (age between 50 and 70 years) participated in the study. The sample underwent a five minutes of eyes‐closed resting MEG recording (N MEG = 24), a cycloergometer incremental exercise test to evaluate CRF through VO2 peak (N stress = 17), and carried an accelerometer for one week to estimate SB (N ACC = 26). The alpha peak frequency at posterior brain areas was extracted, and then its partial correlation to VO peak and the relative sedentary time from the accelerometer data were calculated, respectively, while also controlling for age. Partial correlation between VO2 max and relative sedentary time was calculated as well. Result Statistical analysis yielded a significant direct correlation between VO2 peak and Alpha peak frequency (N=17, rho = 0.504, p‐value = 0.023), while relative sedentary time and Alpha peak frequency showed a significant inverse correlation (N = 20, rho = ‐0.435, p‐value = 0.032). Partial correlation between VO2 peak and relative sedentary time was not significant (N = 17, rho = ‐0.404, p‐value = 0.120). Conclusion Despite the small cohort, results pinpoint a strong influence of both CRF and SB. Greater CRF, described as higher VO2 peak , appears associated with increased alpha frequency in posterior brain regions, a robust biomarker of brain health which is negatively affected in AD. At the same time, higher levels of sedentarism show a strong relation to decreased alpha peak frequency, indicating that low levels of PA might put subjects entering old age at risk.