Long-Term Improvement in Hippocampal-Dependent Learning Ability in Healthy, Aged Individuals Following High Intensity Interval Training.

Physical exercise may reduce dementia risk in aging, but varying reports on its effectiveness make it challenging to ascribe what level of exercise will have significant longer-term effects on important functions such as hippocampal-based learning and memory. This study compared the effect of three different 6-month exercise regimens on hippocampal-dependent cognition in healthy, elderly individuals. Participants, aged 65-85 with no cognitive deficits, were randomly assigned to one of three exercise interventions (low (LIT), medium (MIT), and High intensity interval training (HIIT), respectively). Each participant attended 72 supervised exercise sessions over a 6-month period. A total of 151 participants completed all sessions. Cognitive testing for hippocampal performance occurred monthly, as did blood collection, and continued for up to 5 years following initiation of the study. Multimodal 7 Tesla MRI scans were taken at commencement, 6 and 12 months. After 6 months, only the HIIT group displayed significant improvement in hippocampal function, as measured by paired associative learning (PAL). MRI from the HIIT group showed abrogation of the age-dependent volumetric decrease within several cortical regions including the hippocampus and improved functional connectivity between multiple neural networks not seen in the other groups. HIIT-mediated changes in the circulating levels of brain-derived neurotrophic factor (BDNF) and cortisol correlated to improved hippocampal-dependent cognitive ability. These findings demonstrate that HIIT significantly improves and prolongs the hippocampal-dependent cognitive health of aged individuals. Importantly, improvement was retained for at least 5 years following initiation of HIIT, suggesting that the changes seen in hippocampal volume and connectivity underpin this long-term maintenance. Sustained improvement in hippocampal function to this extent confirms that such exercise-based interventions can provide significant protection against hippocampal cognitive decline in the aged population. The changes in specific blood factor levels also may provide useful biomarkers for choosing the optimal exercise regimen to promote cognitive improvement.

Impact of exercise and/or dietary interventions, and their behaviour change techniques, on quality of life in middle-aged and older women following treatment for cancer: A systematic review.

Many middle-aged or older women are treated for cancer and their quality of life can be significantly impaired following treatment. Exercise and dietary interventions could address this. The aim of this review was to determine whether exercise and/or dietary interventions which are scaffolded by behaviour change theories and techniques are associated with improved quality of life in middle-aged and older women following cancer treatment. Secondary outcomes included self-efficacy, distress, waist circumference, and food variety. A search of CINAHL (EBSCOhost), Embase, MEDLINE (EBSCOhost), PsycINFO, PubMed and Scopus databases up to 17th November 2022 was conducted. A narrative summary was provided. Twenty articles discussing 18 independent randomised controlled trials/interventions were included, with a total of 1754 participants. No studies reported the outcomes of distress or food variety. Exercise and/or dietary interventions had mixed effects on quality of life, self-efficacy and waist circumference (positive effect: n = 4/14; n = 3/5; n = 4/7, respectively). Two-thirds of the interventions (exercise-only, n = 2; exercise and diet, n = 2) that demonstrated an improvement in quality-of-life scores were based upon Social Cognitive Theory. All studies that reported improvements in waist circumference employed combined exercise and dietary interventions, with individualised aspects for the dietary components. Exercise and/or dietary interventions could potentially enhance quality of life and self-efficacy, and reduce waist circumference, in middle-aged and older women treated for cancer. Although findings are currently mixed, avenues for the development of interventions include ensuring there is a theoretical underpinning and incorporating more behaviour change techniques in exercise and/or dietary interventions in this population.

Between-day reliability of cytokines and adipokines for application in research and practice.

Purpose: This study assessed the biological reliability of peripheral human cytokines and adipokines, and the influence of participant characteristics on total error. This has essential application to interventional cytokine measurement to ensure that reported results are interpreted with confidence. Methods: Participants (49% female, 18-85 years, n = 84) completed two consecutive-day testing sessions. Participants provided a venous blood sample at the same time of day across two consecutive days, under standardized participant presentation, including 24-h rested and 12-h fasted conditions. Multiplex immunoassay was used to assess inflammatory analytes from samples (predominantly plasma). Repeat measurements were conducted between-day for total precision quantification, and technical (technique) error was negated from the total to provide an estimate of biological (attributed to participant presentation) error. Results: Whilst there was no evidence of statistically significant biological error, a small amount of biological error was consistently present across most analytes (∼3.3%/0.07 pg/ml), which was largest for measurement of leptin (7.3%/210 pg/ml). There was also an influence of sex on reliability of leptin and adiponectin (total model explained 6-7% of error variation), where females demonstrated the greatest error. Conclusion: Biological error reported in this study should be applied to any future study or individual with a repeated measurement of cytokine concentrations over time that maintain best practice procedures (12-h fasted, 24-h rested). In most cases, raw error should be used, with exceptions for women for measurement of leptin and adiponectin. This approach will ensure that results are reported with certainty for improved reporting of intervention efficacy.

Accuracy of body composition measurement techniques across the age span.

This study investigated the acceptable accuracy of common body composition techniques compared with the reference 4-compartment (4C-R) model, which has not been investigated in a sample with diverse characteristics, including age and sex. Techniques included components of the 4C-R model [dual-energy X-ray absorptiometry, air displacement plethysmography, deuterium dilution (DD)] and surrogate compartment models, which utilised bioelectrical impedance spectroscopy (BIS) rather than DD. Men and women (sex = 1:1, 18-85 years, n = 90) completed body composition testing under best-practice guidance. For measurement of individuals, only the reference 3-compartment (3C-R) equation met acceptable error limits (<5% error among individuals) within the a priori cut-point (80%) for fat-free mass (FFM; CV = 0.52%) and fat mass (FM; CV = 1.61%). However, all investigated techniques reached equivalency to the 4C-R model for FFM on average (CV = 0.52-4.31%), but for FM only the 3C and 4C equations that included quantification of total body water (TBW) by DD or BIS reached equivalency overall (CV = 1.61-6.68%). Sex and age minimally influenced accuracy. Only the 3C-R or 4C-R equations are supported for acceptable individual accuracy for both FFM and FM. For group estimates any investigated technique could be used with acceptable accuracy for FFM; however, for FM, inclusion of TBW measurement within a compartment model is necessary. Novelty: Only the referent 3C and 4C models (including deuterium dilution) provide accurate body composition results that are acceptable for measurement of individuals in the general population. For group estimates of lean mass in the general population, compartments models that include TBW must be used for accurate measurement.

The effects of exercise on the bone health of people with cancer: a systematic review and meta-analysis.

PURPOSE: To determine the pooled effect of exercise on the bone health of people diagnosed with cancer. METHODS: Four electronic databases were systematically searched. Controlled trials that assessed the effect of exercise on the bone mineral density (BMD) or content (BMC) measured by dual-energy x-ray absorptiometry or peripheral quantitative computed tomography in people who had been diagnosed with cancer were included in the study. Random-effect meta-analyses of effect size (ES) were conducted. Sub-group analyses were performed to explore the influence of intervention duration, prescription and participant characteristics. RESULTS: Of 66 full-text articles screened, 22 studies, from 21 interventions, were included (primarily breast/prostate cancer, sample range n = 36-498). When all interventions were grouped, a significant pooled ES was observed for exercise on hip (ES = 0.112, 95% CI: 0.026 to 0.198; p = 0.011) and lumbar spine BMD (ES = 0.269, 95% CI: 0.036 to 0.501; p = 0.024) compared to control. There was also an influence of sex, where females had greater improvements in hip (ES = 0.120, 95% CI: 0.017 to 0.223; p = 0.022) and spine BMD (ES = 0.415, 95% CI: 0.056 to 0.774; p = 0.23) compared to males. CONCLUSION: Overall, exercise regimens of studies included in this review appear to improve bone health at the hip and spine in people diagnosed with cancer. Sub-analyses suggest some influence of sex, where females had greater improvements in BMD compared to males. It is essential that future studies evaluate the dose-response of exercise training on bone health and create exercise protocols that better align with the laws of bone modelling to enhance osteogenic potential.

How body composition techniques measure up for reliability across the age-span.

BACKGROUND: Reliability of body composition measurement techniques is essential to the accurate reporting of intervention outcomes. However, the between-day precision error of commonly used techniques, as well as the reference multi-compartment model, in a population-representative sample are currently unknown. OBJECTIVES: To quantify technical and biological precision error of body composition techniques in comparison to the referent 4-compartment (4C) model. METHODS: Men and women (1:1 ratio; 18-85 years old; n = 90) completed 2 consecutive-day body composition testing sessions, including individual components of the referent 4C model. Testing was undertaken in accordance with best practice guidance for each technique, including standardized presentation and a consistent time of day. Repeat measurements were conducted on day 1 for technical precision, and between-day measurements were conducted for biological precision quantification. RESULTS: On average, all measurements met acceptable error limits and presented typically low technical and biological error [<2% fat-free mass (FFM) and < 3% fat mass (FM) precision error]. For technical precision of FFM, all techniques met a priori cut points (80%; CV = 0.45-0.81%). For FM, all techniques were equivalent to the best-rating method on average (CV = 0.78-1.35%), except air displacement plethysmography (CV = 2.13%). For biological precision, only 3-compartment (3C) and 4C equations sufficiently met the a priori determined cut point for estimates for FFM (CV = 0.77-0.79%), and only DXA met the 80% cut point (CV = 1.17%) for FM. CONCLUSIONS: The primary purpose of a study design is imperative when deciding on body composition assessment techniques used for longitudinal measurements. If reliable longitudinal assessments of FFM are central, a 3C or 4C model may be indicated. If FM is a primary outcome, DXA may be preferable. However, considering the low error rates presented within the current study across a broad age span of healthy adults with implementation of best-practice guidelines, any technique assessed here may be used, provided that strict protocols are adhered to.

The effect of exercise intensity on chronic inflammation: A systematic review and meta-analysis.

OBJECTIVES: Chronic inflammation is independently associated with the incidence and progression of chronic disease. Exercise has been found to reduce chronic inflammation, however the role of exercise intensity (work rate) is unknown. This review aimed to determine the pooled effect of higher- compared to lower-intensity aerobic and resistance exercise on chronic inflammation in adults. DESIGN: Systematic review and meta-analysis. METHODS: Five electronic databases were searched. Intervention trials that assessed the effect of ≥2 different exercise intensities on peripheral markers of chronic inflammation [c-reactive protein (CRP), interleukin (IL)-6, tumour necrosis factor (TNF)-α and IL-10] in adults were included. Random-effect meta-analyses were conducted to calculate the mean difference in change scores between groups [effect size (ES)]. Sub-group analyses were performed to explore the influence of age, chronic disease, body mass index and intervention duration on inflammation heterogeneity. RESULTS: Of 3952 studies identified, 27 were included. There were no significant effects of exercise intensity on IL-6 (ES=-0.039, 95%CI=-0.353-0.275; p=0.806), TNF-α (ES=0.296, 95%CI=-0.184-0.777; p=0.227) and IL-10 (ES=0.007, 95%CI=-0.904-0.919; p=0.987). A significant pooled ES was observed for higher- versus lower-intensity exercise on CRP concentrations, in studies of middle-aged adults (ES=-0.412, 95%CI=-0.821- -0.004, p=0.048) or interventions >9 weeks in duration (ES=-0.520, 95%CI=-0.882--0.159, p=0.005). CONCLUSIONS: Exercise intensity did not influence chronic inflammatory response. However, sub-analyses suggest that higher-intensity training may be more efficacious than lower-intensity for middle-aged adults, or when longer duration interventions are implemented (>9 weeks), in the most commonly-reported analyte (CRP).