Disa J. Smee

Exercise interventions for cognitive function in adults older than 50: a systematic review with meta-analysis

Background Physical exercise is seen as a promising intervention to prevent or delay cognitive decline in individuals aged 50 years and older, yet the evidence from reviews is not conclusive. Objectives To determine if physical exercise is effective in improving cognitive function in this population. Design Systematic review with multilevel meta-analysis. Data sources Electronic databases Medline (PubMed), EMBASE (Scopus), PsychINFO and CENTRAL (Cochrane) from inception to November 2016. Eligibility criteria Randomised controlled trials of physical exercise interventions in community-dwelling adults older than 50 years, with an outcome measure of cognitive function. Results The search returned 12 820 records, of which 39 studies were included in the systematic review. Analysis of 333 dependent effect sizes from 36 studies showed that physical exercise improved cognitive function (0.29; 95% CI 0.17 to 0.41; p<0.01). Interventions of aerobic exercise, resistance training, multicomponent training and tai chi, all had significant point estimates. When exercise prescription was examined, a duration of 45–60 min per session and at least moderate intensity, were associated with benefits to cognition. The results of the meta-analysis were consistent and independent of the cognitive domain tested or the cognitive status of the participants. Conclusions Physical exercise improved cognitive function in the over 50s, regardless of the cognitive status of participants. To improve cognitive function, this meta-analysis provides clinicians with evidence to recommend that patients obtain both aerobic and resistance exercise of at least moderate intensity on as many days of the week as feasible, in line with current exercise guidelines.

Association between Physical Functionality and Falls Risk in Community-Living Older Adults

Ageing-related declines in physiological attributes, such as muscle strength, can bring with them an increased risk of falls and subsequently greater risk of losing independence. These declines have substantial impact on an individuals functional ability. However, the precise relationship between falls risk and physical functionality has not been evaluated. The aims of this study were to determine the association between falls risk and physical functionality using objective measures and to create an appropriate model to explain variance in falls risk. Thirty-two independently living adults aged 65–92 years completed the FallScreen, the Continuous-Scale Physical Functional Performance 10 (CS-PFP10) tests, and the 12-Item Short-Form Health Survey (SF-12). The relationships between falls risk, physical functionality, and age were investigated using correlational and multiple hierarchical regression analyses. Overall, total physical functionality accounted for 24% of variance in an individuals falls risk while age explained a further 13%. The oldest-old age group had significantly greater falls risk and significantly lower physical functional performance. Mean scores for all measures showed that there were substantial (but not significant) differences between males and females. While increasing age is the strongest single predictor of increasing falls risk, poorer physical functionality was strongly, independently related to greater falls risk.

No Improvement of Repeated-Sprint Performance With Dietary Nitrate

PURPOSE Nitrate supplementation improves endurance exercise and single bouts of high-intensity activity, but its effect on repeated sprints is unclear. This study is the first to investigate the effects of acute dietary nitrate supplementation during a high-intensity intermittent-sprint test to exhaustion. METHODS Team-sport athletes (9 male, age 22.3 ± 2.1 y, VO2max 57.4 ± 8.5 mL · kg-1 · min-1; 7 female, age 20.7 ± 1.3 y, VO2max 47.2 ± 8.5 mL · kg-1 · min-1) were assigned to a double-blind, randomized, crossover design. Participants consumed 70 mL of concentrated beetroot juice containing a minimum of 0.3 g of nitrate (NT) or 70 mL of placebo (PL) 2 h before a repeated-sprint protocol involving repeated 8-s sprints with 30-s recovery on a cycle ergometer to exhaustion. RESULTS Fewer sprints (NT = 13 ± 5 vs PL = 15 ± 6, P = .005, d = 0.41) and less total work (NT = 49.2 ± 24.2 kJ vs PL = 57.8 ± 34.0 kJ, P = .027, d = 0.3) were completed in NT relative to PL. However there was no difference in overall mean power output or the mean power output for each individual 8-s sprint. CONCLUSIONS These findings suggest that dietary nitrate is not beneficial for improving repeated-sprint performance, at least when such sprints are near-maximal and frequent in nature. The lack of an effect of nitrate at near-maximal oxygen uptake supports the suggestion that at greater exercise intensities nitrate does not have an ergogenic effect.

Exercise improves reaction time without compromising accuracy in a novel easy-to-administer tablet-based cognitive task

OBJECTIVES Moderate intensity aerobic exercise is known to facilitate cognitive performance but new technologies enable increasing opportunities to investigate this phenomenon under different circumstances. This study aimed to describe the effect of exercise on executive function assessed though a novel tablet-based test. DESIGN Twenty healthy, active participants volunteered to take part in the randomised fully controlled trial. METHODS Participants undertook an initial test of maximal aerobic capacity as well as ventilatory threshold during an incremental cycle test. A touch screen tablet computer was placed in the middle of the handlebars at an angle of approximately 45°, and participants were asked to complete the response-inhibition cognitive task (Speed Match, Lumos Labs Inc.) at set time points. A full familiarisation trial was performed prior to subsequent visits, in which participants completed either the control (no exercise) and exercise (90% ventilatory threshold (VT)) trials in a randomised order. During the 1h trials, the cognitive task was performed prior to, during and post the intervention. Reaction time and accuracy of participant responses were recorded. RESULTS Performing the cognitive task resulted in elevated heart rates and ventilation rates during control and exercise. Exercise facilitated performance in the executive function task such that reaction time was enhanced with no change in accuracy. A range of reliability measures are also reported. CONCLUSIONS This method of assessing executive function during exercise displays face validity and provides promise for further investigation of cognitive function using a simple, short duration, easily administered and widely available test.

The relationship between diet quality and falls risk, physical function and body composition in older adults

OBJECTIVES We aimed to examine associations between diet quality, falls risk, physical function, physical activity and body composition. DESIGN Cross-sectional study. SETTING AND PARTICIPANTS Data collected from 171 men and women, aged 60-88 years old, as part of the Falls Risk and Osteoporosis Longitudinal Study. MEASUREMENTS Dietary Intake (Dietary Questionnaire for Epidemiological Studies Version 2 (DQES v2)), Falls Risk (FES-I, ABC, Berg Balance and Physiological Profile Assessment), Physical Function (SPPB), Physical Activity (PASE) and Body Composition (fat mass, lean mass, BMD, BMI, android/gynoid ratio) were ascertained. Diet quality was determined using two measures (Healthy Eating Index - HEI and Healthy Diet Indicator - HDI). One-way Analysis of Variance was used to compare mean scores between females and males and Pearson product-moment correlation coefficients were calculated to examine bivariate relationships. RESULTS Although females and males were analysed separately, the HDI-total score showed more associations that the HEI in both genders. The HDI showed, in females weak negative associations with BMI (r =-.21, p=.04), gynoid fat (r = -.20, p=.01), total fat mass (r = -.20, p=.02), with a weak positive association between HDI and percentage lean mass (r =.20, p=.03). Males showed positive associations between HDI and age (r =.30 p=.02) physical function (SPPB)(r =.26, p=.04), and subjective falls-risk (ABC) (r =.26, p=.03). In addition, in males, a negative association was found between HDI and FES-I (r = -.25, p=.04). The only measure that was significantly associated with the HEI-total score was the android/gynoid ratio in males (r = -.29, p=.04). When controlling for age, females demonstrated weak positive associations between gynoid (r = .19 p = .02), android (r = .19, p = .02) and total fat mass (r = .20 p = .02) as well as weak negative correlation with lean mass (r = 1.19, p = .03). Age also impacts on the FES-I (r = .29 p <.01) and ABC (r = -.23 p <.01). CONCLUSIONS The relationships between dietary quality and body composition, falls risk and physical function in older community dwelling, higher functioning adults appear to be gender specific. Better diet quality in females, is associated with lower BMI and fat mass, and higher lean mass, compared to males that are older and appear to have better physical function, are less likely to self-report falls risk, and have a better fat distribution i.e. a lower android/gynoid ratio have better diet quality. Furthermore, age is an important confounder and should be taken into consideration when assessing diet quality in older adults. In addition these gender and age differences may be clinically relevant and could aid in the delivery of targeted interventions.

The Relationship Between Subjective Falls-Risk Assessment Tools and Functional, Health-Related, and Body Composition Characteristics

We sought to explore the relationship between two subjective falls-risk assessment tools (Falls Efficacy Scale–International [FES-I] and Activities-Specific Balance Confidence [ABC] Scale) and functional, health-related, and body composition characteristics. A total of 245 community-dwelling people aged 60 to 88 years underwent assessments for subjective falls risk (using the FES-I and ABC Scale), health-related (cognitive; Short-Form Health Survey [SF-12]), functional (physical activity and physical function), and body composition characteristics (measured by dual X-ray absorptiometry). The FES-I and ABC Scale are strongly correlated with each other for females and males (r = −.70, p < .001; r = −.65, p < .001), respectively. There are substantial differences between males and females when they self-assess their risk of falling as well as what characteristics contribute to explaining these self-assessments. Females are potentially more self-aware of their functional, body composition and health-related characteristics to better estimate their own risk of falling. FES-I correlates better with functional, body composition, and health-related characteristics, and thus may be more appropriate for use than the ABC in community-dwelling older adults.

A balance-specific exercise intervention improves falls risk but not total physical functionality in community-dwelling older adults

ABSTRACT Aims: The aim of this research was to investigate whether a simple balance-specific exercise simultaneously improves physical functionality and falls. Methods: Thirty-two community-dwelling individuals aged 65–92 years were assigned to either the control or wobble-board group. Participants were assessed pre- and postintervention using the Physiological Profile Assessment (a measure of falls risk) and the Continuous-Scale Physical Functional Performance-10 (a measure of physical functionality). Results: Participants in the intervention group, wobble-board training, had a decrease in their risk of falling by 36% (p = 0.009, ηρ2 = 0.396), while the control group recorded a slight but nonsignificant increase (6%). No change was seen in their total Continuous-Scale Physical Functional Performance-10 score. Conclusion: A balance-specific intervention decreased falls-risk and improved balance but not sufficiently to affect total physical functionality.

Compression garments and cerebral blood flow: Influence on cognitive and exercise performance

Abstract This study aimed to describe the effect of compression garments on middle cerebral artery blood flow velocity (MCAv) in relation to cognitive and exercise performance whilst cycling. In a randomised-controlled-cross-over design, 15 well-trained male cyclists were recruited to participate in three identical trials wearing loose fitting shorts (control), low-grade, or medium-grade compression garments. The protocol involved four 8 min increments of cycling at 30%, 50%, 70%, and 85% maximal power output and a 4 km time-trial. Participants undertook a cognitive Stroop task at baseline and at the midpoint of each increment. MCAv was monitored with Transcranial Doppler Ultrasonography. Mean arterial pressure (MAP) and partial pressure of end-tidal CO2 (PetCO2) were measured throughout. MCAv, MAP, PetCO2, and reaction time of the complex Stroop task were influenced by exercise intensity, but not compression garments. Compression garments significantly affected cognitive accuracy in the complex Stroop task such that low-grade compression appeared to enhance cognitive accuracy in comparison to the control condition at the highest intensity (p = .010). Time-trial performance did not differ between the control (338.0 ± 17.3 s), low-grade (338.7 ± 18.7 s), or medium-grade (342.2 ± 19.3 s) conditions (p = .114). Compression garments did not affect MCAv during exercise or time-trial performance, but compression may be beneficial for improved cognitive accuracy during high-intensity exercise. Further research is required to elucidate the potential impact on cognitive performance.

Association between Berg Balance, Physiological Profile Assessment and physical activity, physical function and body composition: a cross-sectional study

BACKGROUND Falls are of great concern to older adults and costly to the health system. In addition the relationship between falls risk and falls risk predictor characteristics is complex. OBJECTIVE This study aimed to explore the relationship between two objective fall-risk measures tools, the Physiological Profile Assessment and the Berg Balance Scale and to determine how an individuals sex, level of physical function, health-related and body composition characteristics impact these objective falls risk measures. DESIGN A cross-sectional, observational study. PARTICIPANTS 245 community-dwelling older adults (M age=68.12 years, SD=6.21; 69.8% female). MEASUREMENTS Participants were assessed for falls-risk (Physiological Profile Assessment and the Berg Balance Scale), physical activity, physical functional and body composition characteristics. Pearson product-moment correlation coefficients were calculated to examine bivariate relationships and hierarchical multiple linear regression modelling was used to estimate the contribution of each predictor in explaining variance in falls-risk. RESULTS In females, there was a weak association between the two objective falls-risk measures (r =-0.17 p <0.05). The number of falls in the previous 12 months explained 6% of variance in Physiological Profile Assessment scores, with bone density of the lumbar spine contributing a further 1%. In males and females, variance in the Berg Balance Scale showed that age (25%) and physical function (16% for females, 28% for males) contributed significantly to the explaining variance in the falls-risk measure. CONCLUSION Sex differences are apparent and as such males and females should be assessed (and potentially treated) differently with regards to falls risk. Results indicate that both falls risk assessment tools measure aspects of balance but are not interchangeable. The Berg Balance Scale may be more discriminative in older, less functioning adults and the Physiological Profile Assessment is more useful in assessing falls risk in females.

The effect of high and low exercise intensity periods on a simple memory recognition test

Purpose The purpose of this study was to investigate the effect of variable intensities on a simple memory recognition task during exercise. Methods Twenty active participants took part in initial testing, a familiarization trial and then four 60 min cycling interventions in a randomized order. Interventions consisted of no exercise (control), constant exercise at 90% ventilatory threshold (constant) and 2 trials that initially mimicked the constant trial, but then included periods of high (∼90%VO2peak) and low intensities (∼50%VO2peak). Cardiorespiratory measures and capillary blood samples were taken throughout. A short tablet-based cognitive task was completed prior to and during (50 and 55 min into exercise) each intervention. Results The exercise conditions facilitated response time (p = 0.009), although the extent of this effect was not as strong in the variable exercise conditions (p = 0.011–0.089). High intensity exercise periods resulted in some cognitive regression back towards control trial performance. Elevations in cardiorespiratory measures and periods of hypocapnia could not explain changes in cognitive performance. Conclusion Changes in cognitive performance with variations in exercise intensity are likely to have implications for sport and occupational settings. The timing of cognitive tests to exercise intensity changes as well as use of short cognitive assessments will be important for future work.