The impact of 12 weeks of resistance exercise on hippocampus structural and neurochemical characteristics in older adults: Evidence from MRI and 1H-MRS findings

Abstract

Background and aims Neuroinflammatory processes are considered to mediate age-related hippocampal neurodegeneration. Physical exercise enhances hippocampal neuroplastic potential by modulating neurotrophic and inflammatory markers. This study investigated the relationship between resistance exercise and changes in blood biomarker levels, hippocampal neurometabolite levels, hippocampal volume in older adults with low and high risk of mild cognitive impairment (MCI).

Methods Participants were randomized to exercise (n = 31) or control group (n = 41). The exercise group performed four resistance exercises over 12 weeks in 2 days/week. We assessed serum levels of insulin-like growth factor-1, interleukin-6, and kynurenine. Hippocampal total and subfield volumes of the cornu ammonis (CA) 1–4, subiculum, presubiculum, and dentate gyrus were measured with magnetic resonance imaging. Hippocampus neurometabolites were measured with proton magnetic resonance spectroscopy (1H-MRS), including total N-acetyl aspartate (tNAA), myo-inositol (mIns), total creatine.

Results Seventy participants aged 60 to 85 years completed the study. Older adults with high MCI risk had higher kynurenine levels (p = 0.015) and lower subiculum volumes (p = 0.043) than those with low MCI risk. Exercise-induced hippocampal tNAA/mIns level change was negatively correlated with CA1 volume change (r = −0.605, p = 0.006). Resistance exercise had no significant effect on any of the outcomes.

Conclusions This study may serve future strategies to improve the neuroplastic capacity of the hippocampus, such as designing individualized exercise prescriptions at alternative intensities and frequencies. Further investigation is needed to assess the potential benefits of resistance exercise in older adults.