Physical activity and cognitive function in middle-aged adults: a cross-sectional analysis of the PATH through life study.

Objectives: Investigate the independent associations of objectively measured or self-reported physical activity at different intensities with cognitive performance in middle-aged adults. Design: Cross-sectional. Methods: 156 middle-aged adults (age: 40.6 ± 1.5, 58.3% female) participated in the physical activity sub-study of the Personality and Total Health through life (PATH) project. Physical activity was measured objectively with the SenseWear™ armband (SWA), worn for seven consecutive days, and measured via self-report with a Physical Activity Recall survey (PAR). Cognitive performance was assessed with the Symbol Digit Modalities Test, the Digit Span Backwards, and an Immediate and Delayed Recall task. Associations between physical activity intensity and cognitive function were investigated in general linear models, controlling for age, sex, and education. Results: Neither objectively measured nor self-reported physical activity were associated with cognitive function at light-, moderate-, vigorous-, or combined moderate-to-vigorous intensity in this cohort of well educated, healthy middle-aged adults. Sensitivity analyses with additional moderators (e.g., body mass index, hypertension, alcohol intake) and the use of composite cognitive measures did not alter the results. Conclusion: In this cohort of middle-aged adults, objectively measured and self-reported physical activity do not appear to be associated with cognitive function. Longitudinal follow-ups utilising objective physical activity measures may be important in determining the impact of mid-life behaviours on the trajectory of cognitive changes into older age.

Effects of Exercise Rehabilitation on Physical Function in Adults With Hematological Cancer Receiving Active Treatment: A Systematic Review and Meta-Analysis.

OBJECTIVE: Evaluate the efficacy of exercise rehabilitation at improving physical function during active treatment for adults diagnosed with a hematological malignancy. DATA SOURCE: Systematic review with a multilevel meta-analysis of randomized trails was conducted. Four electronic databases, MEDLINE (EBSCOhost), CINAHL, Scopus, and CENTRAL, were searched using key words and medical subject headings. Articles were screened and assessed against the predetermined eligibility criteria. Data extracted were appraised using the Cochrane risk of bias tool for randomized trials and the GRADE guidelines. A meta-analysis examined four key clinical objectives. CONCLUSION: Twelve studies representing a total of 812 participants were included. Analysis of 36 dependent effect sizes from nine studies revealed structured and prescribed exercise interventions improved physical function (SMD = 0.39; 95% CI 0.21-0.57) compared to usual care or an active control. Exercise interventions with a multimodal design consisting of both aerobic and resistance exercise had a statistically significant effect on physical function (P < .001). Exercise intensity also had a statistically significant effect on physical function when prescribed at a moderate (P = .003) and vigorous (P < .001) intensity during active treatment in patients with leukemia or lymphoma. IMPLICATIONS FOR NURSING PRACTICE: This review suggests individuals diagnosed with leukemia or lymphoma can optimize physical function during and immediately post-treatment by attending exercise rehabilitation 3-5 times per weeks performing moderate-vigorous aerobic and resistance exercise. While further research is needed to identify optimal prescription guidelines throughout the treatment continuum, this review underscores the importance for hematology nurses to support patient referrals to exercise oncology professionals to gain positive improvements in physical function.

The accuracy of self-reported physical activity questionnaires varies with sex and body mass index.

BACKGROUND: Factors contributing to the accurate measurement of self-reported physical activity are not well understood in middle-aged adults. We investigated the associations between two self-reported surveys and objectively measured physical activity in middle-aged adults, and the influence of individual and sociodemographic factors on these associations, at different intensities utilizing an observational study design. METHODS: Participants (n = 156) wore a SenseWear Armband™ (SWA) for a continuous seven-day period over the triceps of the left arm, to measure energy expenditure in metabolic equivalents. Participants also completed the Physical Activity Recall questionnaire (PAR) and Active Australia Survey (AAS). Associations were analyzed separately in general linear models for each intensity. The influence of individual and sociodemographic factors was assessed through moderator analyses. RESULTS: The PAR and SWA were significantly positively associated at moderate (ß = 0.68, 95% CI 0.16-1.20), vigorous (ß = 0.36, 95% CI 0.20-0.53), moderate-to-vigorous physical activity (MVPA) (ß = 0.52, 95% CI 0.20-0.83), and total METmins (ß = 0.63, 95% CI 0.35-0.90), the AAS and SWA were associated at all intensities (moderate (ß = 0.41, 95% CI 0.15-0.67), vigorous (ß = 0.32, 95% CI 0.19-0.46), MVPA (ß = 0.42, 95% CI 0.18-0.65) and total METmins (ß = 0.62, 95% CI 0.29-0.96). A significant interaction between the PAR and sex for vigorous-intensity unveiled a weaker association in women. Both surveys tended to under-report physical activity. The largest margins of error were present at light and moderate intensities. For the PAR, participants reported over 20 hours, or 69% less light physical activity than recorded by the SWA per week. For the AAS, participants reported over 7 hours, or 38% less moderate physical activity. Compared to lighter intensities, time spent at a vigorous intensity was overreported by participants with the PAR and AAS by 91 and 43 minutes per week, respectively. The addition of Body Mass Index (BMI) resulted in non-significant interactions between the PAR and SWA for moderate-intensity, and the AAS and SWA for vigorous-intensity; a significant interaction between AAS and BMI indicated that the strength of the association differed by BMI for vigorous-intensity. CONCLUSIONS: The PAR and AAS are not equivalent to the SWA, and sex and BMI may alter the associations between the measures.

A Short-Term Intervention of High-Intensity Exercise and Anodal-tDCS on Motor Learning in Middle-Aged Adults: An RCT.

High-intensity exercise has enhanced motor learning in healthy young adults. Anodal-transcranial direct current stimulation (a-tDCS) may optimize these effects. This study aimed to determine the effects of a short-term high-intensity interval exercise intervention either with or without a-tDCS on the learning and retention of a novel motor task in middle-aged adults. Forty-two healthy middle-aged adults (age = 44.6 ± 6.3, female = 76%) were randomized into three groups: exercise and active a-tDCS, exercise and sham a-tDCS, and a non-exercise and sham a-tDCS control. Participants completed a baseline testing session, followed by three intervention sessions 48-h apart. The exercise groups completed 20-min of high-intensity exercise followed by a novel sequential visual isometric pinch task (SVIPT) while receiving 20-min of 1.5 mA a-tDCS, or sham tDCS. The control group completed 20-min of reading before receiving sham a-tDCS during the SVIPT. Learning was assessed by skill change within and between intervention sessions. Participants returned 5-7 days after the final intervention session and performed the SVIPT task to assess retention. All three groups showed evidence of learning on the SVIPT task. Neither group displayed enhanced overall learning or retention when compared to the control group. High-intensity exercise with or without a-tDCS did not improve learning or retention of a novel motor task in middle-aged adults. The methodological framework provides direction for future research to investigate the potential of differing exercise intensity effects on learning and retention.

Objectively measured physical activity is associated with dorsolateral prefrontal cortex volume in older adults.

BACKGROUND: Epidemiological studies suggest physical activity (PA) can slow or prevent both cognitive decline and age-related atrophy in frontal and hippocampal gray matter volumes. However, much of this evidence is based on self-reported measures of PA. METHODS: PA was measured objectively with a SenseWear™ Armband to examine the cross-sectional associations between the duration of light, moderate and vigorous intensity PA with gray matter volume in the dorsolateral prefrontal cortex (DLPFC) and hippocampus in 167 (female: 43%) cognitively healthy older adults aged 73 to 78. RESULTS: The duration of objective moderate to vigorous intensity physical activity (MVPA) was associated with a greater volume of the right DLPFC (ߠ​= â€‹0.16; p â€‹= â€‹0.04). In addition, objective moderate-intensity PA alone was also associated with greater volume of the left (ߠ​= â€‹0.17; p â€‹= â€‹0.03) and right (ߠ​= â€‹0.19; p â€‹= â€‹0.01) DLPFC after controlling for covariates and adjustment for multiple comparisons. In contrast, there were no significant associations between light- or vigorous-intensity PA and gray matter volumes (all p â€‹> â€‹0.05). No associations between PA and cognitive performance were detected, and self-reported PA was not associated with any of the outcomes investigated. CONCLUSIONS: These findings suggest that an intensity-dependent relationship may exist, whereby a greater duration of MVPA, perhaps driven by moderate-intensity PA, is associated with preserved gray matter volume in frontal regions of the brain. Future research should investigate the mechanisms of this dose-effect and determine whether greater brain volumes associated with objective PA convey protective effects against cognitive decline.

A 4-week endurance training program improves tolerance to mental exertion in untrained individuals.

OBJECTIVES: The aim of this study was to investigate whether 4 weeks of endurance training could improve tolerance to mental exertion in untrained participants. DESIGN: Longitudinal training study. METHODS: Twenty untrained young adults (14 F, 6 M; 27.6±6.2 years) completed a 4-week training protocol in a randomised and counterbalanced order. Baseline and follow-up assessment were conducted over three sessions in the week preceding and following the training period. During session 1, participants completed an incremental maximal ramp test. During sessions 2 and 3 participants completed a 15min cycling time trial preceded by either a mental exertion or control conditions. Following baseline assessments, participants were randomised into a physical training or placebo group that completed the training intervention thrice weekly over four weeks. RESULTS: The physical training resulted in increase in VO2 peak relative to the placebo group (p=0.003). Linear Mixed Models utilising the control condition time trial performance as a covariate found the physical training group increased their time trial distance following the mental exertion condition to a greater extent than the placebo group (p=0.03). RPE during the time trial and perceptual measures of mental exertion did not significantly change between groups (all p>0.10) although interaction effects were observed when considering the RPE-power output relationship during the time trial. CONCLUSIONS: Four weeks of endurance training increased tolerance to mental exertion in untrained participants during a subsequent physical performance, but not during prolonged cognitive performance. This finding suggests that the ability to tolerate mental exertion is trainable in at least some contexts and highlights the far-reaching benefits of endurance training.

Can the intensity of physical activity be accurately measured in older adults using questionnaires?

OBJECTIVES: This study assessed the accuracy of two questionnaires for measuring the duration of physical activity (PA) by intensity compared to an objective measure in older adults. DESIGN: Cross-sectional observation METHODS: A total of 169 (female=43.8%) participants aged 73-78 years (mean: 75.1 y; SD: 1.3) wore a SenseWear™ Armband (SWA) for seven-days and reported the duration of PA by intensity with a Physical Activity Recall (PAR) questionnaire and the Active Australia Survey (AAS). In addition, the duration of moderate-to-vigorous-PA (MVPA) and overall active time, weighted for intensity (Total PA; MET: min/week) was assessed. Univariate general linear models were used to compare the questionnaire and SWA measures of PA while controlling for age, sex and education. RESULTS: The PAR was associated with SWA moderate intensity PA (b=0.19; 95% CI 0.03-0.35), MVPA (b=0.19; 95% CI 0.02-0.37) and Total PA (b=0.33; 95% CI 0.11-0.55). Although significant correlations were present, the models explained a small proportion of the variance in the SWA variables. The AAS was not associated with the SWA for any PA outcome. There was also significant under-reporting of PA duration for both questionnaires in comparison to the SWA. CONCLUSIONS: The PAR questionnaire may be suitable for determining the effect of greater levels of PA on health outcomes. However, neither questionnaire can be considered valid in determining the duration of PA divided by intensity. In addition, questionnaire and objectively measured PA are not equivalent and absolute measures of PA derived from questionnaires should be interpreted with caution.

Cognition in breast cancer survivors: A pilot study of interval and continuous exercise.

OBJECTIVES: The current study investigated the effects of two exercise interventions on cognitive function amongst breast cancer survivors. DESIGN: Pilot randomised-controlled trial. METHODS: Seventeen female cancer survivors (mean: 62.9±7.8years) were randomised into three groups: high-intensity interval training (HIIT, n=6); moderate-intensity continuous training (MOD, n=5); or wait-list control (CON, n=6). The HIIT and MOD groups exercised on a cycle ergometer 3days/week for 12-weeks. Primary outcomes were cognitive function assessments utilising CogState. Secondary outcomes were resting middle cerebral artery blood flow velocity, cerebrovascular reactivity and aerobic fitness (VO2peak). Data were analysed with General Linear Mixed Models and Cohen's d effect sizes were calculated. RESULTS: All 17 participants who were randomised were available for follow-up analysis and adherence was similar for HIIT and MOD (78.7±13.2% vs 79.4±12.0%; p=0.93). Although there were no significant differences in the cognitive and cerebrovascular outcomes, HIIT produced moderate to large positive effects in comparison to MOD and CON for outcomes including episodic memory, working memory, executive function, cerebral blood flow and cerebrovascular reactivity. HIIT significantly increased VO2peak by 19.3% (d=1.28) and MOD had a non-significant 5.6% (d=0.72) increase, compared to CON which had a 2.6% decrease. CONCLUSIONS: This study provides preliminary evidence that HIIT may be an effective exercise intervention to improve cognitive performance, cerebrovascular function and aerobic fitness in breast cancer survivors. Considering the sample size is small, these results should be confirmed through larger clinical trials.

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

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.

Middle cerebral artery blood flow velocity during a 4 km cycling time trial.

PURPOSE: This study sought to describe middle cerebral artery blood flow velocity (MCAv) during a 4 km cycling time trial, and relate it to different pacing strategies adopted by participants. METHODS: After familiarisation and a standardised exercise protocol, 15 male trained cyclists rode a 4 km time trial on a cycling ergometer. MCAv was assessed via transcranial Doppler ultrasound in the right hemisphere at resting baseline, and throughout the time trial. Mean arterial pressure, end-tidal partial pressure of carbon dioxide (PetCO2) and heart rate were assessed alongside MCAv. Plasma lactate was assessed post time trial. Data were compared depending upon whether participants completed the time trial with a positive (first half faster than the last) or negative pacing profile although there was no difference in the time to completion with either pacing strategy (positive 344 ± 23 s, negative 334 ± 14 s; p = 0.394). RESULTS: Lower mean MCAv (positive pacing -7.6 ± 14.2%, negative pacing +21.2 ± 15.0% compared to resting baseline measures; p = 0.004) and lower PetCO2 (significant interaction p < 0.001) towards the end of the time trial were observed with positive compared to negative pacing. Heart rate and lactate did not differ between pacing strategies. CONCLUSIONS: Changes in MCAv appear to depend on the pacing strategy adopted, with a positive pacing strategy likely to contribute to a hyperventilatory drop in PetCO2 and subsequent reduction in MCAv. Although lower cerebral blood flow cannot be directly linked to an inability to raise or maintain power output during the closing stages of the time trial, this potential contributor to fatigue is worth further investigation.

Vascular Occlusion and Sequential Compression for Recovery After Resistance Exercise.

The purpose of this study was to evaluate vascular occlusion (OCC) and sequential intermittent pneumatic compression (SIPC) as recovery strategies after fatiguing resistance exercise. Twelve strength-trained male participants (age: 24.0 ± 6.3 years, height: 180.4 ± 9.7 cm, and weight: 84.8 ± 9.6 kg) participated in a randomized cross-over study. Participants performed a fatiguing resistance exercise bout consisting of 10 sets with 10 repetitions of back squats at 70% 1 repetition maximum with 3-minute rest between sets. Outcome measures of perceived recovery status, muscle soreness, concentric peak isokinetic torque of the quadriceps, squat jump (SJ) height, and countermovement jump (CMJ) height were taken before the fatiguing resistance exercise bout and repeated immediately post, 1 hour, and 24 hours later. Immediately after the postexercise measures, participants undertook 1 of the 3 recovery strategies: OCC, SIPC, and a passive control (CON). Concentric peak isokinetic torque of the quadriceps was decreased significantly immediately post and 1 hour after the fatiguing resistance exercise bout compared with baseline values (p ≤ 0.05). Mean SJ and CMJ jump height decreased significantly immediately post and 1 hour compared with baseline measures, but only the SJ was significantly decreased at 24 hours. There were no significant differences between conditions for any of the postexercise measures (p > 0.05). In conclusion, this study indicates that OCC and SIPC are not effective for attenuating muscle performance loss after a fatiguing resistance exercise bout relative to passive recovery.