School of Public Health

Permanent URI for this communityhttp://hdl.handle.net/1903/1633

The collections in this community comprise faculty research works, as well as graduate theses and dissertations.

Note: Prior to July 1, 2007, the School of Public Health was named the College of Health & Human Performance.

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Author: search.filters.author.Alfini, Alfonso J.

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    Cardiorespiratory Fitness as a Moderator of Sleep-Related Associations with Hippocampal Volume and Cognition
    (MDPI, 2022-10-07) Alfini, Alfonso J.; Won, Junyeon; Weiss, Lauren R.; Nyhuis, Casandra C.; Zipunnikov, Vadim; Spira, Adam P.; Liu-Ambrose, Teresa; Shackman, Alexander J.; Smith, J. Carson
    The objective of this study was to understand the associations of sleep and cardiorespiratory fitness with hippocampal volume and global cognition among older adults (n = 30, age = 65.8 years, female = 73.3%). Wrist actigraphy provided objective measures of nighttime sleep including sleep duration, average wake bout length (WBL; sleep disturbance), and wake-to-sleep transition probability (WTSP; sleep consolidation). Cardiorespiratory fitness was quantified via cycle exercise using a modified heart rate recovery approach. Magnetic resonance imaging was used to determine hippocampal volume and the Mini-Mental State Examination was used to assess global cognition. Fitness moderated associations of sleep with hippocampal volume and cognitive performance, whereby the association of WBL—an index of poor sleep—with hippocampal atrophy was stronger among less-fit individuals, and the association of sleep duration with cognitive performance was stronger among more-fit individuals. Across the fitness levels, a longer WBL was associated with lower cognitive performance, and a higher WTSP—an index of more consolidated sleep—was associated with greater hippocampal volume. Sleep and fitness were unrelated to the volume of an amygdala control region, suggesting a degree of neuroanatomical specificity. In conclusion, higher cardiorespiratory fitness may attenuate sleep disturbance-related hippocampal atrophy and magnify the cognitive benefits of good sleep. Prospective studies are needed to confirm these findings.
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    THE IMPACT OF ACUTE EXERCISE AND SLEEP QUALITY ON EXECUTIVE FUNCTION: THE POTENTIAL MEDIATING EFFECTS OF FUNCTIONAL CONNECTIVITY IN OLDER ADULTS
    (2017) Alfini, Alfonso J.; Smith, J. Carson; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Background: Although, improved longevity is a major public health accomplishment, the prevalence of chronic disease, including cognitive impairment, increases with age. Insufficient sleep and physical inactivity exacerbate chronic disease and may accelerate the onset of dementia. While a cure remains elusive, a growing body of evidence demonstrates that exercise training facilitates better sleep and enhanced cognition. Exercise-altered patterns of neural activity, including resting state functional connectivity (rsFC) and task-based functional activation, likely coincide with and may facilitate cognitive improvements in the aging brain. Purpose: This study sought to examine the joint impact of acute exercise and sleep quality on executive function in older adults. We also aimed to determine the degree to which exercise-induced changes in prefrontal rsFC influence the relationship between sleep and executive function performance/functional activation. Methods: Using a within subjects counter-balanced design, 21 participants (aged 55-85) underwent at least three days of objective sleep monitoring (actigraphy), followed by two experimental visits on separate days. During each visit, participants engaged in 30-minutes of rest or exercise followed immediately by resting state and task-based functional MRI. After the MRI scanning session, participants completed several executive function assessments. Neuroimaging and behavioral data were processed using AFNI (version 17.1.06) and SPSS (version 23), respectively. Results: Repeated measures ANOVA and multivariate linear regression revealed two significant voxel-wise interactions in the (L) precuneus. Our findings demonstrated that acute exercise increased prefrontal rsFC and functional activation in long sleepers (> 7.5 hours/night), while decreasing these parameters for individuals with less total sleep time. Moreover, these results correspond to behavioral data demonstrating that acute exercise and adequate sleep improved select aspects of executive function performance, while decreasing inhibitory control in short sleepers alone (< 7.5 hours). Conclusion: These findings suggest that the effects of acute exercise on prefrontal rsFC are similar, or even related, to the effects of acute exercise on conflict-dependent functional activation, and that this relationship may depend on sleep duration. Moreover, our results imply that although acute exercise elicited improved executive function for those with adequate sleep, it may weaken already vulnerable, and perhaps fatigued, executive function networks among short sleepers.
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    Hippocampal and Cerebral Blood Flow after Exercise Cessation in Master Athletes
    (Frontiers, 2016-08-05) Alfini, Alfonso J.; Weiss, Lauren R.; Leitner, Brooks P.; Smith, Theresa J.; Hagberg, James M.; Smith, J. Carson
    While endurance exercise training improves cerebrovascular health and has neurotrophic effects within the hippocampus, the effects of stopping this exercise on the brain remain unclear. Our aim was to measure the effects of 10 days of detraining on resting cerebral bloodflow (rCBF) in gray matter and the hippocampus in healthy and physically fit older adults. We hypothesized that rCBF would decrease in the hippocampus after a 10-day cessation of exercise training. Twelve master athletes, defined as older adults (age ≥ 50 years) with long-term endurance training histories (≥ 15 years), were recruited from local running clubs. After screening, eligible participants were asked to cease all training and vigorous physical activity for 10 consecutive days. Before and immediately after the exercise cessation period, rCBF was measured with perfusion-weighted MRI. A voxel-wise analysis was used in gray matter, and the hippocampus was selected a priori as a structurally defined region of interest (ROI), to detect rCBF changes overtime. Resting CBF significantly decreased in eight gray matter brain regions. These regions included: (L) inferior temporal gyrus, fusiform gyrus, inferior parietal lobule, (R) cerebellar tonsil, lingual gyrus, precuneus, and bilateral cerebellum (FEW p < 0.05). Additionally, rCBF within the left and right hippocampus significantly decreased after 10 days of no exercise training. These findings suggest that the cerebrovascular system, including the regulation of resting hippocampal blood flow, is responsive to short-term decreases in exercise training among master athletes. Cessation of exercise training among physically fit individuals may provide a novel method to assess the effects of acute exercise and exercise training on brain function in older adults.