The interaction between physical activity and sleep on cognitive function and brain beta-amyloid in older adults

Mechanisms, Consequences and Role of Interventions for Sleep Deprivation: Focus on Mild Cognitive Impairment and Alzheimer's Disease in Elderly

Sleep is established as an essential physiological need that impacts physical, emotional, and cognitive functions profoundly. Physiologically, inadequate sleep weakens immune function, heightening susceptibility to infections and chronic illnesses such as obesity, diabetes, and cardiovascular diseases. Hormonal disruptions due to sleep loss further exacerbate metabolic dysregulation, contributing to weight gain and other health complications. Emotionally, sleep deprivation leads to mood disturbances, including increased irritability, heightened stress responses, and a greater likelihood of mood disorders like depression and anxiety. These effects are compounded by cognitive impairments such as reduced alertness, impaired memory consolidation, and compromised decision-making abilities, akin to the impairments caused by alcohol consumption. Motor skills and coordination also suffer, elevating the risk of accidents, particularly in high-stress environments. For older adults, sleep quality is closely linked to cognitive function and overall longevity. Optimal sleep patterns are associated with slower brain aging and improved health outcomes. However, sleep disorders exacerbate existing conditions such as epilepsy and asthma, necessitating interventions like cognitive behavioral therapy (CBT) and medications such as melatonin to mitigate their impact. Education emerges as a crucial tool in promoting healthier sleep habits across all age groups. Addressing misconceptions about sleep and integrating sleep health into public health policies are essential steps toward improving overall well-being. Additionally, lifestyle factors such as diet and physical activity play significant roles in regulating sleep patterns, further emphasizing the interconnectedness of sleep with broader health outcomes. In summary, the articles underscore the intricate mechanisms through which sleep influences physiological functions and advocate for comprehensive approaches to enhance sleep hygiene and mitigate the adverse effects of sleep deprivation on human health.

Sleep and physical activity measures are associated with resting-state network segregation in non-demented older adults

Greater physical activity and better sleep are associated with reduced risk of cognitive decline and dementia among older adults, but little is known about their combined associations with measures of brain function and neuropathology. This study investigated potential independent and interactive cross-sectional relationships between actigraphy-estimated total volume of physical activity (TVPA) and sleep patterns [i.e., total sleep time (TST), sleep efficiency (SE)] with resting-state functional magnetic resonance imaging (rs-fMRI) measures of large scale network connectivity and positron emission tomography (PET) measures of amyloid-β. Participants were 135 non-demented older adults from the BIOCARD study (116 cognitively normal and 19 with mild cognitive impairment; mean age = 70.0 years). Using multiple linear regression analyses, we assessed the association between TVPA, TST, and SE with connectivity within the default-mode, salience, and fronto-parietal control networks, and with network modularity, a measure of network segregation. Higher TVPA and SE were independently associated with greater network modularity, although the positive relationship of SE with modularity was only present in amyloid-negative individuals. Additionally, higher TVPA was associated with greater connectivity within the default-mode network, while greater SE was related to greater connectivity within the salience network. In contrast, longer TST was associated with lower network modularity, particularly among amyloid-positive individuals, suggesting a relationship between longer sleep duration and greater network disorganization. Physical activity and sleep measures were not associated with amyloid positivity. These data suggest that greater physical activity levels and more efficient sleep may promote more segregated and potentially resilient functional networks and increase functional connectivity within specific large-scale networks and that the relationship between sleep and functional networks connectivity may depend on amyloid status.

Actigraphy Estimated Sleep Moderates the Relationship between Physical Activity and Cognition in Older Adults

Background and Aims

Physical inactivity and poor sleep are common in older adults and may interact to contribute to age- and disease-related cognitive decline. However, prior work regarding the associations among physical activity, and cognition in older adults is primarily limited to subjective questionnaires that are susceptible to inaccuracies and recall bias. Therefore, this study examined whether objectively measured physical activity and sleep characteristics, each estimated using actigraphy, are independently or interactively associated with cognitive performance.

Methods

The study included 157 older adults free of dementia (136 cognitively unimpaired; 21 MCI; M age = 71.7) from the BIOCARD cohort.

Results

Using multiple linear regression, cognition was regressed on estimated total volume of physical activity (TVPA), sleep efficiency (SE), wake after sleep onset (WASO), and total sleep time (TST) (adjusted for age, sex, education, diagnosis, vascular risk factors, and Apolipoprotein E (APOE)-e4 genetic status). Models were also run for domain-specific cognitive composite scores. TVPA and SE each were positively associated with a global cognitive composite score. TVPA was positively associated with executive function and language composites, and SE was positively related to executive function, visuospatial, and language composites. Importantly, a TVPA by SE interaction (p = 0.015) suggested that adults with the poorest SE experienced the greatest benefit from physical activity in relation to global cognition. The other sleep metrics were unrelated to cognitive performance.

Conclusion

These results suggest that TVPA and SE may synergistically benefit cognition in older adults.

Interaction effect of midday napping duration and depressive symptoms on subjective memory impairment among older people in China: evidence from the China health and retirement longitudinal study database

BACKGROUND

Subjective memory impairment (SMI) is common in older people. The aim of this study was to investigate the factors influencing SMI among older people in China, with specific focus on the interaction effect of midday napping duration and depressive symptoms on the risk of SMI.

METHODS

Using a dataset representative of the Chinese population from a longitudinal study of health and retirement in China, subjects with SMI were screened using the question "how do you feel about your memory now?" and the Mini-Mental State Examination. A logistic regression model was applied to explore the factors affecting SMI. Additive and multiplicative models were used to analyze the interaction effect of midday napping duration and depressive symptoms on the risk of SMI.

RESULTS

We enrolled 8,254 subjects included and the incidence of SMI was 63.9%. Depressive symptoms, nap time, and physical activity were influencing factors of SMI. Midday napping duration and depressive symptoms had positive additive interaction effects on the risk of SMI. When extended-length naps and depressive symptoms coexisted, the risk of SMI was 1.06 times greater than that for either alone (RERI, relative excess risk due to interaction = 0.27, 95% CI = 0.07-0.43; AP, attributable proportion = 0.14, 95% CI = 0.01-0.23; S, synergy index = 1.06, 95% CI = 0.57-1.62). When short naps and depressive symptoms coexisted, the risk of SMI was 1.2 times higher than that for either alone (RERI = 0.12, 95% CI=-0.14-0.39; AP = 0.13, 95% CI=-0.07-0.22; S = 1.20, 95% CI = 0.79-1.82).

LIMITATIONS

Since this was a cross-sectional study, the cause-and-effect relationships between the associated variables cannot be inferred.

CONCLUSIONS

The interaction effect that exists between nap time and depressive symptoms in older people is important for the identification and early intervention of people at risk for SMI.

The effect of acute exercise on objectively measured sleep and cognition in older adults

Background

Exercise can improve cognition in aging, however it is unclear how exercise influences cognition, and sleep may partially explain this association. The current study aimed to investigate whether objectively measured sleep mediates the effect of an acute exercise intervention on cognition in older adults.

Methods

Participants were 30 cognitively unimpaired, physically active older adults (69.2 ± 4.3 years) with poor sleep (determined via self-report). After a triple baseline cognitive assessment to account for any natural fluctuation in cognitive performance, participants completed either a single bout of 20-minutes of high intensity exercise on a cycle ergometer, or a control condition, in a cross-over trial design. Cognition was measured immediately post-intervention and the following day, and sleep (total sleep time, sleep onset latency, sleep efficiency, % of rapid eye movement sleep, light sleep and deep sleep) was characterized using WatchPAT™ at baseline (5 nights) and measured for one night after both exercise and control conditions.

Results

Results showed no effect of the exercise intervention on cognition immediately post-intervention, nor an effect of acute exercise on any sleep variable. There was no mediating effect of sleep on associations between exercise and cognition. However, a change from baseline to post-intervention in light sleep and deep sleep did predict change in episodic memory at the ~24 h post-intervention cognitive assessment, regardless of intervention condition.

Discussion

There was no effect of acute high intensity exercise on sleep or cognition in the current study. However, results suggest that associations between sleep and cognition may exist independently of exercise in our sample. Further research is required, and such studies may aid in informing the most effective lifestyle interventions for cognitive health.

The influence of baseline sleep on exercise-induced cognitive change in cognitively unimpaired older adults: A randomised clinical trial

OBJECTIVES

Observational studies consistently demonstrate that physical activity is associated with elevated cognitive function, however, there remains significant heterogeneity in cognitive outcomes from randomized exercise interventions. Individual variation in sleep behaviours may be a source of variability in the effectiveness of exercise-induced cognitive change, however this has not yet been investigated. The current study aimed to (1) investigate the influence of a 6-month exercise intervention on sleep, assessed pre- and post-intervention and, (2) investigate whether baseline sleep measures moderate exercise-induced cognitive changes.

METHODS

We utilised data from the Intense Physical Activity and Cognition (IPAC) study (n = 89), a 6-month moderate intensity and high intensity exercise intervention, in cognitively unimpaired community-dwelling older adults aged 60-80 (68.76 ± 5.32). Exercise was supervised and completed on a stationary exercise bicycle, and cognitive function was measured using a comprehensive neuropsychological battery administered pre- and post-intervention. Sleep was measured using the Pittsburgh sleep quality index. There was no effect of the exercise intervention on any sleep outcomes from pre- to post-intervention.

RESULTS

There was a significant moderating effect of baseline sleep efficiency on both episodic memory and global cognition within the moderate intensity exercise group, such that those with poorer sleep efficiency at baseline showed greater exercise-induced improvements in episodic memory.

CONCLUSIONS

These results suggest that those with poorer sleep may have the greatest exercise-induced cognitive benefits and that baseline sleep behaviours may be an important source of heterogeneity in previous exercise interventions targeting cognitive outcomes.

Clinical observation and mechanism of acupuncture on amnestic mild cognitive impairment based on the gut-brain axis: study protocol for a randomized controlled trial

Background

Amnestic mild cognitive impairment (aMCI) is a pre-dementia condition associated with declined cognitive function dominated by memory impairment. The occurrence of aMCI is associated with the gut-brain axis. Previous studies have shown cognitive improvements in MCI after acupuncture treatment. This study evaluates whether acupuncture can produce a therapeutic effect in patients with aMCI by modulating the gut-brain axis.

Methods and design

This is a prospective, parallel, multicenter randomized controlled trial. A total of 40 patients with aMCI will be randomly assigned to an acupuncture group (AG) or a waiting-list group (WG), participants in both groups will receive health education on improving cognitive function at each visit, and acupuncture will be conducted twice a week for 12 weeks in the AG. Another 20 matched healthy volunteers will be enrolled as normal control. The primary outcome will be the change in Alzheimer's Disease Assessment Scale-cognitive scale score before and after treatment. Additionally, functional magnetic resonance imaging data, faeces, and blood will be collected from each participant to characterize the brain function, gut microbiota, and inflammatory cytokines, respectively. The differences between patients with aMCI and healthy participants, and the changes in the AG and WG groups before and after treatment will be observed. Ultimately, the correlation among brain function, gut microbiota, inflammatory cytokines, and clinical efficacy evaluation in patients with aMCI will be analyzed.

Discussion

This study will identify the efficacy and provide preliminary data on the possible mechanism of acupuncture in treating aMCI. Furthermore, it will also identify biomarkers of the gut microbiota, inflammatory cytokines, and brain function correlated with therapeutic effects. The results of this study will be published in peer-reviewed journals.

Clinical trial registration

http://www.chictr.org.cn, identifier ChiCTR2200062084.

Sleep Quality, Metabolic Function, Physical Activity, and Neurocognition Among Individuals with Resistant Hypertension

BACKGROUND

Resistant hypertension (RH) is a major risk factor for stroke, cognitive decline, and dementia. Sleep quality is increasingly suggested to play an important role linking RH to cognitive outcomes, although the mechanisms linking sleep quality to poor cognitive function have yet to be fully delineated.

OBJECTIVE

To delineate biobehavioral mechanisms linking sleep quality, metabolic function, and cognitive function among 140 overweight/obese adults with RH in the TRIUMPH clinical trial.

METHODS

Sleep quality was indexed using actigraphy measures of sleep quality and sleep fragmentation, as well as self-reported sleep quality from the Pittsburgh Sleep Quality Index (PSQI). Cognitive function was assessed using a 45-minute battery assessing executive function, processing speed, and memory. Participants were randomized to a cardiac rehabilitation-based lifestyle program (C-LIFE) or a standardized education and physician advice condition (SEPA) for 4 months.

RESULTS

Better sleep quality at baseline was associated with better executive function (B = 0.18 p = 0.027), as well as greater fitness (B = 0.27, p = 0.007) and lower HBA1c (B = -0.25, p = 0.010). Cross-sectional analyses revealed that the sleep quality executive function association was mediated by HBA1c (B = 0.71 [0.05, 2.05]). C-LIFE improved sleep quality (-1.1 [-1.5, -0.6] versus+-0.1 [-0.8, 0.7]) and actigraphy steps (+922 [529, 1316] versus+56 [-548, 661]), with actigraphy mediating improvements in executive function (B = 0.40 [0.02, 1.07]).

CONCLUSION

Better metabolic function and improved physical activity patterns levels play important roles linking sleep quality and executive function in RH.

Knowledge, Awareness, and Attitude of Healthcare Stakeholders on Alzheimer's Disease and Dementia in Qatar

Dementia is characterized by progressive cognitive decline, memory impairment, and disability. Alzheimer's disease (AD) accounts for 60-70% of cases, followed by vascular and mixed dementia. Qatar and the Middle East are at increased risk owing to aging populations and high prevalence of vascular risk factors. Appropriate levels of knowledge, attitudes, and awareness amongst health care professionals (HCPs) are the need of the hour, but literature indicates that these proficiencies may be inadequate, outdated, or markedly heterogenous. In addition to a review of published quantitative surveys investigating similar questions in the Middle East, a pilot cross-sectional online needs-assessment survey was undertaken to gauge these parameters of dementia and AD among healthcare stakeholders in Qatar between 19 April and 16 May 2022. Overall, 229 responses were recorded between physicians (21%), nurses (21%), and medical students (25%), with two-thirds from Qatar. Over half the respondents reported that >10% of their patients were elderly (>60 years). Over 25% reported having contact with >50 patients with dementia or neurodegenerative disease annually. Over 70% had not undertake related education/training in the last 2 years. The knowledge of HCPs regarding dementia and AD was moderate (mean score of 5.3 ± 1.5 out of 7) and their awareness of recent advances in basic disease pathophysiology was lacking. Differences existed across professions and location of respondents. Our findings lay the groundwork for a call-to-action for healthcare institutions to improve dementia care within Qatar and the Middle East region.

Twenty-four-hour time-use composition and cognitive function in older adults: Cross-sectional findings of the ACTIVate study

Introduction

Physical activity, sedentary behaviour and sleep are associated with cognitive function in older adults. However, these behaviours are not independent, but instead make up exclusive and exhaustive components of the 24-h day. Few studies have investigated associations between 24-h time-use composition and cognitive function in older adults. Of these, none have considered how the quality of sleep, or the context of physical activity and sedentary behaviour may impact these relationships. This study aims to understand how 24-h time-use composition is associated with cognitive function across a range of domains in healthy older adults, and whether the level of recreational physical activity, amount of television (TV) watching, or the quality of sleep impact these potential associations.

Methods

384 healthy older adults (age 65.5 ± 3.0 years, 68% female, 63% non-smokers, mean education = 16.5 ± 3.2 years) participated in this study across two Australian sites (Adelaide, n = 207; Newcastle, n = 177). Twenty-four-hour time-use composition was captured using triaxial accelerometry, measured continuously across 7 days. Total time spent watching TV per day was used to capture the context of sedentary behaviours, whilst total time spent in recreational physical activity was used to capture the context of physical activity (i.e., recreational accumulation of physical activity vs. other contexts). Sleep quality was measured using a single item extracted from the Pittsburgh Sleep Quality Index. Cognitive function was measured using a global cognition index (Addenbrooke's Cognitive Examination III) and four cognitive domain composite scores (derived from five tests of the Cambridge Neuropsychological Test Automated Battery: Paired Associates Learning; One Touch Stockings of Cambridge; Multitasking; Reaction Time; Verbal Recognition Memory). Pairwise correlations were used to describe independent relationships between time use variables and cognitive outcomes. Then, compositional data analysis regression methods were used to quantify associations between cognition and 24-h time-use composition.

Results

After adjusting for covariates and false discovery rate there were no significant associations between time-use composition and global cognition, long-term memory, short-term memory, executive function, or processing speed outcomes, and no significant interactions between TV watching time, recreational physical activity engagement or sleep quality and time-use composition for any cognitive outcomes.

Discussion

The findings highlight the importance of considering all activities across the 24-h day against cognitive function in older adults. Future studies should consider investigating these relationships longitudinally to uncover temporal effects.