Raji 2016 J Alzheimers Dis
| Raji CA, Merrill DA, Eyre H, Mallam S, Torosyan N, Erickson KI, Lopez OL, Becker JT, Carmichael OT, Gach HM, Thompson PM, Longstreth WT, Kuller LH (2016) Longitudinal relationships between caloric expenditure and gray matter in the cardiovascular health study. J Alzheimers Dis 2016 Mar 11 52:719-29. |
Raji CA, Merrill DA, Eyre H, Mallam S, Torosyan N, Erickson KI, Lopez OL, Becker JT, Carmichael OT, Gach HM, Thompson PM, Longstreth WT, Kuller LH (2016) J Alzheimers Dis
Abstract: BACKGROUND: Physical activity (PA) can be neuroprotective and reduce the risk for Alzheimer's disease (AD). In assessing physical activity, caloric expenditure is a proxy marker reflecting the sum total of multiple physical activity types conducted by an individual.
OBJECTIVE: To assess caloric expenditure, as a proxy marker of PA, as a predictive measure of gray matter (GM) volumes in the normal and cognitively impaired elderly persons.
METHODS: All subjects in this study were recruited from the Institutional Review Board approved Cardiovascular Health Study (CHS), a multisite population-based longitudinal study in persons aged 65 and older. We analyzed a sub-sample of CHS participants 876 subjects (mean age 78.3, 57.5% F, 42.5% M) who had i) energy output assessed as kilocalories (kcal) per week using the standardized Minnesota Leisure-Time Activities questionnaire, ii) cognitive assessments for clinical classification of normal cognition, mild cognitive impairment (MCI), and AD, and iii) volumetric MR imaging of the brain. Voxel-based morphometry modeled the relationship between kcal/week and GM volumes while accounting for standard covariates including head size, age, sex, white matter hyperintensity lesions, MCI or AD status, and site. Multiple comparisons were controlled using a False Discovery Rate of 5 percent.
RESULTS: Higher energy output, from a variety of physical activity types, was associated with larger GM volumes in frontal, temporal, and parietal lobes, as well as hippocampus, thalamus, and basal ganglia. High levels of caloric expenditure moderated neurodegeneration-associated volume loss in the precuneus, posterior cingulate, and cerebellar vermis.
CONCLUSION: Increasing energy output from a variety of physical activities is related to larger gray matter volumes in the elderly, regardless of cognitive status.
Labels: MiParea: Exercise physiology;nutrition;life style
Pathology: Aging;senescence, Alzheimer's, Neurodegenerative
Organism: Human
Preparation: Intact organism
Quotations
- Several lines of evidence suggest that sedentary behavior may be a risk factor for the development of age-related cognitive impairment. .. A 25% reduction in sedentary behavior could potentially prevent more than 1 million AD cases globally. From a mechanistic perspective, sedentary behaviors may contribute to risk of AD and dementia by two main factors [7, 8]. First, they are associated with increased cardiovascular and metabolic risk factors, such as diabetes, hypertension, and obesity [9], which are associated with increased risk of dementia [10, 11]. Second, sedentary behaviors appear to have direct effects on neurobiological processes. A recent review [12] outlines evidence to suggest that sedentary behavior may have detrimental effects on the brain via reducing neurogenesis, synaptic plasticity, neurotrophin production, angiogenesis, and by increasing inflammation.
- Our findings of exercise-influenced GM volume increases are supported by other studies that utilized MRI to demonstrate: i) a linear correlation between high fitness levels and large hippocampal volumes in elderly participants [16, 52], ii) the association of high levels of physical activity in predicting large volumes of frontal, occipital, and entorhinal regions [16], iii) an association between large hippocampal volumes and a reduced risk of developing AD [16], and iv) a correlation between increased hippocampal volume and improvement in short-term memory test scores [53]. Animal studies also support our findings, where models for causal inference showed exercise has been found to increase the incorporation of new neurons into the hippocampus [54].
- A recent review by Voelcker-Rehage and Niemann [59, 60] compares the clinical effect of ‘metabolic exercise’ (i.e., cardiovascular and resistance training) and coordinative PA (i.e., motor fitness, coordination, and flexibility) on cognitive function and markers of neuroplasticity. The authors present evidence arguing pure metabolic PA has greater effects on brain volume and functional activity, particularly in the prefrontal and hippocampal areas, as compared to stretching, toning, or relaxation interventions (for primary evidence, see [18, 61, 62]);they contribute this effect to differing metabolic demands [59].
