IntroductionMetabolic syndrome (MetS) has been recognized as one of the most important clinical challenges and global health issues of today. Growing evidence suggests that mechanisms of energy metabolism may also play a key role in mediating aspects of cognitive function. Brain-derived neurotrophic factor (BDNF) is one such factor well known for its critical role in neuronal plasticity, including memory and learning, and more recently metabolic processes. BDNF levels have been shown separately to be dependent on diet and exercise programming.PurposeThe purpose of this study was to investigate the effect of diet and exercise on BDNF levels and cognitive functioning with any metabolic association in individuals characterized with MetS.MethodsTwelve subjects with MetS followed a randomized crossover design with two four-week interventions, including a carbohydrate (CHO)-restricted Paleolithic-based diet (CRPD; <50gCHO) with sedentary activity (CRPD-Sed) and CRPD with high intensity interval training (HIIT; CRPD-Sed), separated by a four-week washout period. The HIIT exercise consisted of 10 x 60 s cycling intervals interspersed with 60 s of active recovery 3 day/week for four-week. Serum BDNF was detected and quantified via enzyme-linked immunosorbent assay (ELISA). Cognitive executive function (Stroop Test) and self-perceived cognitive symptoms and function (MOS-CFS) were quantified. A two-way analysis of variance with repeated measures was performed with post-hoc analysis using simple effects analysis with a Bonferroni adjustment. The level of statistical significance was established a priori as P < 0.05.ResultsCompared to baseline, CRPD-Sed and CRPD-Ex improved variables for cognitive function, including increased peripheral serum BDNF levels (20% and 38%), psychomotor speed and cognitive flexibility (-14%, -14%), and self-perceived cognitive symptoms and functioning (+8%, +16%), respectively. BDNF inversely correlated with %body fat (r = -0.35, P < 0.05), fasting glucose (r = -0.64, P < 0.05), triglycerides (r = -0.55, P < 0.05), and insulin sensitivity (r = -0.25, P < 0.05).ConclusionThis study shows the short-term beneficial effects of carbohydrate-restricted diet on serum BDNF and executive function in those individuals characterized with MetS. We have shown that the addition of exercise can further improve neuroprotection and cognitive function beyond the results of diet alone.

Context: Version 5 of the Sport Concussion Assessment Tool (SCAT5) was released in 2017 with an additional 10-word list option in the memory section and additional instructions for completing the symptom scale.Objective: To provide reference scores for high school rugby union players on the SCAT5, including immediate memory using the 10-word list, and examine how age, sex, and concussion history affected performance.Design: Cross-sectional study. Setting: Calgary, Alberta high schools.Patients or Other Participants: High school rugby union players (ages 15-18 years) participating in a 2018 season cohort study (n ¼ 380, males ¼ 210, females ¼ 170).Main Outcome Measure(s): Sport Concussion Assessment Tool 5 scores, including total number of symptoms (of 20), symptom severity (of 132), 10-word immediate memory (of 30), delayed memory (of 10), modified Standardized Assessment of Concussion (of 50), and balance examination (of 30).Results: The median number of symptoms reported at baseline ranged from 5 to 8 across sex and age stratifications. Median symptom severity was lowest in males with no concussion history (7; range, 0-28) and highest in females with a concussion history (13, range ¼ 0-45). Median total scores on immediate memory were 2-3 (range ¼ 0-4) for males and 21 (range ¼ 9-29) for females. Median total scores were 3 (range ¼ 0-4) on digits backward and 7 (range ¼ 0-20) on delayed memory (all groups). Based on simultaneous quantile (q) regression at 0.50 and 0.75, adjusted for age and concussion history, being female was associated with a higher total symptoms score (q0.75 b female ¼ 2.85; 99% confidence interval [CI] ¼ 0.33, 5.37), higher total symptom severity score (q0.75 b female ¼ 8.00; 99% CI ¼ 2.83, 13.17), and lower number of errors on the balance examination (q0.75 b female ¼ À3.00; 99% CI ¼ À4.85, À1.15). Age and concussion history were not associated with any summary measures.Conclusions: The 10-word list option in the memory section reduced the likelihood of a ceiling effect. A player's sex may be an important consideration when interpreting the SCAT5 after concussion.Despite changes to the instructions for the baseline symptoms assessment, the majority of high school rugby players reported symptoms at baseline. Addition of the 10-word list to version 5 of the Sport Concussion Assessment Tool eliminated a ceiling effect for memory scores in high school rugby players. This study informs the use and interpretation of the Sport Concussion Assessment Tool, version 5, in Alberta high school rugby players and indicates that reporting of symptoms is normal at baseline in this age group.

Background: Ultra-short-term (UST) heart rate variability (HRV) metrics have increasingly been proposed as surrogates for short-term HRV metrics. However, the concurrent validity, within-day reliability, and between-day reliability of UST HRV have yet to be comprehensively documented. Methods: Thirty-six adults (18 males, age: 26 ± 5 years, BMI: 24 ± 3 kg/m2) were recruited. Measures of HRV were quantified in a quiet-stance upright orthostatic position via three-lead electrocardiogram (ADInstruments, FE232 BioAmp). All short-term data recordings were 300-seconds in length and five UST time points (i.e., 30-seconds, 60-seconds, 120-seconds, 180-seconds, and 240-seconds) were extracted from the original 300-second recording. Bland-Altman plots with 95% limits of agreement, repeated measures ANOVA, and two-tailed paired t-tests demarcated differences between UST and short-term recordings. Linear regressions, coefficient of variation, intraclass correlation coefficients, and other tests examined the validity and reliability in both time- and frequency-domains. Results: No group differences were noted between all short-term and UST measures, for either time- (all p>0.202) or frequency-domain metrics (all p>0.086). A longer recording duration was associated with augmented validity and reliability, that was less impacted by confounding influences from physiological variables (e.g., respiration rate, carbon dioxide end-tidals, and blood pressure). Conclusively, heart rate, time-domain, and relative frequency-domain HRV metrics were acceptable with recordings greater or equal to 60s, 240s, and 300s, respectively. Conclusions: Future studies employing UST HRV metrics, should thoroughly understand the methodological requirements to obtain accurate results. Moreover, a conservative approach should be utilized regarding the minimum acceptable recording duration, which ensures valid/reliable HRV estimates are obtained.

This is an open access article under the terms of the Creat ive Commo ns Attri bution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Objective. Currently, a recording of 300 s is recommended to obtain accurate dynamic cerebral autoregulation estimates using transfer function analysis (TFA). Therefore, this investigation sought to explore the concurrent validity and the within- and between-day reliability of TFA estimates derived from shorter recording durations from squat-stand maneuvers. Approach. Retrospective analyses were performed on 70 young, recreationally active or endurance-trained participants (17 females; age: 26 ± 5 years, [range: 20–39 years]; body mass index: 24 ± 3 kg m−2). Participants performed 300 s of squat-stands at frequencies of 0.05 and 0.10 Hz, where shorter recordings of 60, 120, 180, and 240 s were extracted. Continuous transcranial Doppler ultrasound recordings were taken within the middle and posterior cerebral arteries. Coherence, phase, gain, and normalized gain metrics were derived. Bland–Altman plots with 95% limits of agreement (LOA), repeated measures ANOVA’s, two-tailed paired t-tests, coefficient of variation, Cronbach’s alpha, intraclass correlation coefficients, and linear regressions were conducted. Main results. When examining the concurrent validity across different recording durations, group differences were noted within coherence (F (4155) > 11.6, p < 0.001) but not phase (F (4155) < 0.27, p > 0.611), gain (F (4155) < 0.61, p > 0.440), or normalized gain (F (4155) < 0.85, p > 0.359) parameters. The Bland–Altman 95% LOA measuring the concurrent validity, trended to narrow as recording duration increased (60 s: < ±0.4, 120 s: < ±0.3, 180 s  < ±0.3, 240 s: < ±0.1). The validity of the 180 and 240 s recordings further increased when physiological covariates were included within regression models. Significance. Future studies examining autoregulation should seek to have participants perform 300 s of squat-stand maneuvers. However, valid and reliable TFA estimates can be drawn from 240 s or 180 s recordings if physiological covariates are controlled.

Changes in exertion-related symptoms in adults and youth who have sustained a sport-related concussion. Rutschmann, Trevor Dean Rutschmann, T. D. (2018). Changes in exertion-related symptoms in adults and youth who have sustained a sport-related concussion (Unpublished master's thesis).

IntroductionOne approach to slow the pandemic of obesity and chronic disease is to look to our evolutionary past for clues of the changing behaviors contributing to the emergence of 'diseases of civilization'. Modern humans have deviated from the lifestyle behaviors of our ancestors that have introduced pressures (i.e. diet and activity changes) quicker than our genetic ability to respond. This caused a 'mismatch' between our biological systems and environment, leading to 'man-made' chronic diseases.PurposeThe purpose of the study was to investigate the effects of a short-term evolutionarily informed dietary and lifestyle intervention on inflammatory and cardio-metabolic profiles in individuals characterized as having metabolic syndrome (MetS).MethodsTwelve subjects with MetS followed a crossover design with two, four-week interventions, including a carbohydrate (CHO)-restricted Paleolithic-based diet (CRPD; <50g CHO) with sedentary activity (CRPD-Sed) and CRPD with high-intensity interval training (CRPD-Ex), separated by a four-week washout period. The HIIT exercise consisted of 10 X 60 seconds (s) cycling intervals interspersed with 60s of active recovery three d/wk for four weeks. The effects of a diet with sedentary activity as compared to a diet with exercise on body composition, as well as the cardiovascular, inflammatory, and metabolic profiles, were assessed. A two-way analysis of variance (ANOVA) with repeated measures was performed with a post-hoc analysis using a simple effects analysis with a Bonferroni adjustment. The level of statistical significance was established a priori as p < 0.05.ResultsCompared to baselines, CRPD-Sed and CRPD-Ex improved cardio-metabolic markers, including reductions in waist adiposity (-15%, -18%), body mass (-3%, -5%), body fat % (BF%; -7%, -12%), fasting plasma glucose (GLU; -20%, -27%), triglycerides (TG; -47%, -52%), fasting insulin (-34%, -39%), insulin resistance (-35%, -46%), and increased HDL-C (+22%, +36%) and VO2max (+22% and +29%), respectively. CRPD-Sed and CRPD-Ex also reduced inflammatory markers, including hsCRP (-32% and-36%), TNF-alpha (-35% and -41%), IL-6 (-29% and -40%), and ICAM-1 (-19%, -23%), respectively, when compared to baseline.ConclusionAdopting behaviors from our evolutionary past, including diet and exercise, shows favorable cardio-metabolic and inflammatory profiles in those individuals characterized with MetS.

Introduction: Moderate-intensity aerobic exercise increases cerebral blood velocity (CBv) primarily due to hyperpnea-induced vasodilation; however, the integrative control of cerebral blood flow (CBF) allows other factors to contribute to vasodilation. Lower body negative pressure (LBNP) can reduce CBv, the exact LBNP-intensity required to blunt the aforementioned exercise-induced CBv response is unknown. This could hold utility for concussion recovery, allowing individuals to exercise at higher-intensities without symptom exacerbation. Methods: Thirty-two healthy adults (age: 20-33 years; 19 females) completed a stepwise maximal-exercise test to determine each participant's wattage associated with their exercise-induced maximal CBv increase. During the second visit, participants completed moderate-intensity exercise at their determined threshold, while progressive LBNP was applied at 0, -20, -40, -60, -70, -80, and ~88 Torr. Bilateral middle cerebral artery blood velocities (MCAv), mean arterial pressure (MAP), heart rate, respiratory rate, and end-tidal carbon dioxide levels were measured continuously. Two-way analysis of variance with effect sizes compared between sexes and stages. Results: Compared to resting-supine baseline, averaged MCAv was elevated during 0 and -20 Torr LBNP (q-value>7.73; p<0.001); no differences were noted between baseline and -40 to -70 Torr (q-value<|4.24|; p>0.262). Differences were present between females and males for absolute MCAv measures (q-value>11.2; p<0.001), but not when normalized to baseline (q-value<0.03; p>0.951). Conclusion: Supine cycling-elicited increases in MCAv were blunted during the application of LBNP ranging from -40 to -70 Torr. The blunted CBv response demonstrates the potential benefit of allowing individuals to aerobically train (moderate-intensity supine cycling with LBNP) without exacerbating symptoms during concussion recovery.