Low-intensity daily walking activity is associated with hippocampal volume in older adults.

TitleLow-intensity daily walking activity is associated with hippocampal volume in older adults.
Publication TypeJournal Article
Year of Publication2015
AuthorsVarma, VR, Chuang, Y-F, Harris, GC, Tan, EJ, Carlson, MC
JournalHippocampus
Volume25
Issue5
Pagination605-15
Date Published2015 May
ISSN1098-1063
KeywordsActigraphy, Aged, Exercise, Female, Hippocampus, Humans, Linear Models, Magnetic Resonance Imaging, Male, Organ Size, Sex Characteristics, Thalamus, Walking
Abstract

Hippocampal atrophy is associated with memory impairment and dementia and serves as a key biomarker in the preclinical stages of Alzheimer's disease. Physical activity, one of the most promising behavioral interventions to prevent or delay cognitive decline, has been shown to be associated with hippocampal volume; specifically increased aerobic activity and fitness may have a positive effect on the size of the hippocampus. The majority of older adults, however, are sedentary and have difficulty initiating and maintaining exercise programs. A modestly more active lifestyle may nonetheless be beneficial. This study explored whether greater objectively measured daily walking activity was associated with larger hippocampal volume. We additionally explored whether greater low-intensity walking activity, which may be related to leisure-time physical, functional, and social activities, was associated with larger hippocampal volume independent of exercise and higher-intensity walking activity. Segmentation of hippocampal volumes was performed using Functional Magnetic Resonance Imaging of the Brain's Software Library (FSL), and daily walking activity was assessed using a step activity monitor on 92, nondemented, older adult participants. After controlling for age, education, body mass index, cardiovascular disease risk factors, and the Mini Mental State Exam, we found that a greater amount, duration, and frequency of total daily walking activity were each associated with larger hippocampal volume among older women, but not among men. These relationships were specific to hippocampal volume, compared with the thalamus, used as a control brain region, and remained significant for low-intensity walking activity, independent of moderate- to vigorous-intensity activity and self-reported exercise. This is the first study, to our knowledge, to explore the relationship between objectively measured daily walking activity and hippocampal volume in an older adult population. Findings suggest the importance of examining whether increasing nonexercise, lifestyle physical activities may produce measurable cognitive benefits and affect hippocampal volume through molecular pathways unique to those related to moderate-intensity exercise.

DOI10.1002/hipo.22397
Alternate JournalHippocampus
PubMed ID25483019
PubMed Central IDPMC4425252
Grant ListP01AG027735-03 / AG / NIA NIH HHS / United States
K01 AG031332 / AG / NIA NIH HHS / United States
T32 AG000247 / AG / NIA NIH HHS / United States
P30-AG021334 / AG / NIA NIH HHS / United States
T32 AG027668 / AG / NIA NIH HHS / United States
P50 AG005146 / AG / NIA NIH HHS / United States
P01 AG027735 / AG / NIA NIH HHS / United States
P30 AG021334 / AG / NIA NIH HHS / United States
R01 HL077141 / HL / NHLBI NIH HHS / United States
R01 HL089694 / HL / NHLBI NIH HHS / United States
RC1 HL099340 / HL / NHLBI NIH HHS / United States
R21 CA127511 / CA / NCI NIH HHS / United States
U01 AG022376 / AG / NIA NIH HHS / United States

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