Hippocampal neurochemicals are associated with exercise group and intensity, psychological health, and general cognition in older adults.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 36626020 · doi:10.1007/s11357-022-00719-9
What was done
Sixty-three older adults (mean age 75.3 ± 1.9 years) from the Generation 100 study were randomized to either a supervised exercise group (SEG; twice-weekly moderate- to high-intensity training) or a control group (CG; following national physical activity guidelines of ≥30 min moderate physical activity ≥5 days/week) for 3 years. After 3 years, participants underwent 3T magnetic resonance imaging and magnetic resonance spectroscopic imaging to measure hippocampal body and head volumes and metabolites (N-acetyl aspartate [NAA], choline [Cho], and creatine [Cr]). Peak oxygen uptake (VO2peak), psychological health, and cognition were also assessed, with general linear models adjusted for age, sex, education, and hippocampal volume.
What was found
Both groups adhered to their interventions, with SEG exercising at higher intensity. SEG had significantly lower NAA/Cr in the hippocampal body than CG (p = 0.04). Across all participants, higher training intensity was associated with lower Cho/Cr in the hippocampal body (p < 0.001). Changes in VO2peak, baseline-to-3-year VO2peak increases, and 3-year VO2peak were not associated with hippocampal neurochemicals. Lower NAA/Cr in the hippocampal body was associated with poorer psychological health and slightly higher cognitive scores.
Why it matters
Contrary to expectations that supervised higher-intensity exercise would yield superior neurochemical benefits, following general moderate physical activity guidelines was associated with a more favorable hippocampal metabolite profile after 3 years.
Limits
The sample size was small (n = 63). Baseline neurochemical measurements were not reported, preventing analysis of within-subject longitudinal changes. Specific cognitive measures and exact effect sizes for metabolite concentrations were not detailed in the abstract.
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- contradicts A randomized trial in older adults showed that Norwegian 4x4 high-intensity interval training produced superior improvements in hippocampal function and structure maintenance compared to moderate-intensity training, with benefits maintained for 5 years.