title: Changes in fitness are associated with changes in hippocampal microstructure and hippocampal volume among older adults.
abstract: This study investigates the effects of fitness changes on hippocampal microstructure and hippocampal volume. Fifty-two healthy participants aged 59-74years with a sedentary lifestyle were randomly assigned to either of two levels of exercise intensity. Training lasted for six months. Physical fitness, hippocampal volumes, and hippocampal microstructure were measured before and after training. Hippocampal microstructure was assessed by mean diffusivity, which inversely reflects tissue density; hence, mean diffusivity is lower for more densely packed tissue. Mean changes in fitness did not differ reliably across intensity levels of training, so data were collapsed across groups. Multivariate modeling of pretest-posttest differences using structural equation modeling (SEM) revealed that individual differences in latent change were reliable for all three constructs. More positive changes in fitness were associated with more positive changes in tissue density (i.e., more negative changes in mean diffusivity), and more positive changes in tissue density were associated with more positive changes in volume. We conclude that fitness-related changes in hippocampal volume may be brought about by changes in tissue density. The relative contributions of angiogenesis, gliogenesis, and/or neurogenesis to changes in tissue density remain to be identified.
authors.affiliation: Max Planck Institute for Human Development, Lentzeallee 94, 14195 Berlin, Germany. Electronic address: kleemeyer@mpib-berlin.mpg.de.
authors.forename: Maike Margarethe
authors.initials: MM
authors.lastname: Kleemeyer
authors.affiliation: Max Planck Institute for Human Development, Lentzeallee 94, 14195 Berlin, Germany; University Clinic Hamburg-Eppendorf, Clinic and Polyclinic for Psychiatry and Psychotherapy, Martinistrasse 52, 20246 Hamburg, Germany. Electronic address: kuehn@mpib-berlin.mpg.de.
authors.forename: Simone
authors.initials: S
authors.lastname: Kühn
authors.affiliation: Max Planck Institute for Human Development, Lentzeallee 94, 14195 Berlin, Germany. Electronic address: prindle@mpib-berlin.mpg.de.
authors.forename: John
authors.initials: J
authors.lastname: Prindle
authors.affiliation: Max Planck Institute for Human Development, Lentzeallee 94, 14195 Berlin, Germany. Electronic address: bodammer@mpib-berlin.mpg.de.
authors.forename: Nils Christian
authors.initials: NC
authors.lastname: Bodammer
authors.affiliation: SMS Medical Institute Berlin/Berliner Akademie für Sportmedizin e.V., Olympiapark Berlin, Hanns-Braun-Straße/Adlerplatz, 14053 Berlin, Germany. Electronic address: lars.brechtel@medical-institute-berlin.de.
authors.forename: Lars
authors.initials: L
authors.lastname: Brechtel
authors.affiliation: German Center for Neurodegenerative Diseases, Fetscherstraße 105, 01307 Dresden, Germany. Electronic address: alexander.garthe@dzne.de.
authors.forename: Alexander
authors.initials: A
authors.lastname: Garthe
authors.affiliation: German Center for Neurodegenerative Diseases, Fetscherstraße 105, 01307 Dresden, Germany; Center for Regenerative Therapies TU Dresden, Fetscherstraße 105, 01307 Dresden, Germany. Electronic address: gerd.kempermann@dzne.de.
authors.forename: Gerd
authors.initials: G
authors.lastname: Kempermann
authors.affiliation: Max Planck Institute for Human Development, Lentzeallee 94, 14195 Berlin, Germany; Leipzig University, Sportwissenschaftliche Fakultät, Jahnallee 59, 04109 Leipzig, Germany. Electronic address: sabine.schaefer@uni-leipzig.de.
authors.forename: Sabine
authors.initials: S
authors.lastname: Schaefer
authors.affiliation: Max Planck Institute for Human Development, Lentzeallee 94, 14195 Berlin, Germany; European University Institute, Via dei Roccettini 9, 50014 San Domenico di Fiesole (FI), Italy. Electronic address: seklindenberger@mpib-berlin.mpg.de.
authors.forename: Ulman
authors.initials: U
authors.lastname: Lindenberger
mesh_terms: D000368:Aged; D000375:Aging / Q000473:pathology* / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods; D015444:Exercise / Q000502:physiology; D005260:Female; D006624:Hippocampus / Q000166:cytology* / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009473:Neuronal Plasticity / Q000502:physiology; D009929:Organ Size / Q000502:physiology; D064797:Physical Conditioning, Human / Q000379:methods*; D010809:Physical Fitness / Q000502:physiology*; D057185:Sedentary Behavior
keywords: Aging; Fitness; Hippocampal microstructure; Hippocampal volume; Latent difference modeling; Physical exercise