Sport-related concussion alters cerebral hemodynamic activity during controlled respiration.

Sport-related concussion (SRC) is known to disrupt neurohemodynamic activity, cardiac function, and blood pressure (BP) autoregulation. This study aims to observe changes in cerebrovascular and cardiovascular responses during controlled respiration after sustaining an SRC. University varsity athletes (n = 81) completed a preseason physiological assessment and were followed up within 5 days of sustaining an SRC. During preseason and follow-up assessments, participants' continuous beat-to-beat BP was collected by finger photoplethysmography, and right prefrontal cortex oxygenation was collected using near-infrared spectroscopy (NIRS). Participants completed 5 min of seated rest and 5 min of a 6-breaths per minute controlled breathing protocol (5 s inhale and 5 s exhale; 0.10 Hz). Wavelet transformation was applied to the NIRS and BP signals, separating them into respiratory (0.10-0.6 Hz) and cardiac (0.6-2 Hz) frequency intervals. Of the 81 participants, 74 had a usable BP signal, 43 had usable NIRS signals, and 28 had both usable BP and NIRS signals. Wavelet amplitudes were calculated and coherence between NIRS and BP on the 28 participants were assessed. There was a significant (P < 0.05) decrease in oxygenated hemoglobin amplitude from 0.062 to 0.054 Hz and hemoglobin difference amplitude from 0.059 to 0.051 Hz, both at the respiratory (0.10-0.6 Hz) frequency interval, from preseason to acute SRC, respectively. Therefore, during controlled respiration, there was a reduction in intensity at the respiratory band, suggesting a protective, reduced respiratory contribution to cerebral hemodynamic activity following acute SRC.NEW & NOTEWORTHY This study investigated cerebral hemodynamic activity following sport-related concussion. Prefrontal cortex oxygenation was assessed by near-infrared spectroscopy (NIRS) during a controlled breathing protocol. Wavelet transformation of the NIRS signals showed significant decreases in HbO2 and HbD amplitude at the respiratory frequency interval (0.10-0.6 HZ) from preseason baseline to acute concussion. These results suggest a decreased respiratory contribution to cerebral hemodynamic activity following acute concussion.

Differences in Heart Rate Variability and Baroreflex Sensitivity between Male and Female Athletes.

Heart rate variability (HRV), systolic blood pressure variability (BPV), and spontaneous baroreflex sensitivity (BRS) are indirect and approximate measures of autonomic regulation of the cardiovascular system. Studies have shown differences in HRV and BRS between males and females; however, no study has observed differences in BPV, HRV, or BRS between male and female athletes. One hundred males (age 21.2 ± 2.1 y; BMI 27.4 ± 4.5 kg/m2) and sixty-five females (age: 19.7 ± 1.6 y; BMI 22.7 ± 2.2 kg/m2) were assessed during the pre-season baseline. We collected resting beat-to-beat blood pressure and R-R intervals using finger photoplethysmography and a 3-lead electrocardiogram, respectively. Participants underwent a controlled slow breathing protocol (six breaths/minute: 5 s inhale, 5 s exhale) for 5 min. Spectral and linear analysis was conducted on blood pressure and ECG data. Regression curves were fitted to the blood pressure and R-R signals, with the slopes providing the BRS parameters. Male athletes had significantly (p < 0.05) lower mean heart rate, RR interval SD2/SD1, HRV % low-frequency, and higher BP high-frequency power during controlled respiration. No differences were found in any BRS parameters. HRV and BPV responses to a slow breathing protocol differed between male and female athletes; however, BRS responses did not.

Alterations in Baroreflex Sensitivity and Blood Pressure Variability Following Sport-Related Concussion.

Current methods to diagnose concussions are subjective and difficult to confirm. A variety of physiological biomarkers have been reported, but with conflicting results. This study assessed heart rate variability (HRV), spontaneous baroreflex sensitivity (BRS), and systolic blood pressure variability (BPV) in concussed athletes. The assessment consisted of a 5-min seated rest followed by a 5-min (0.1 Hz) controlled breathing protocol. Thirty participants completed baseline assessments. The protocol was repeated during the post-injury acute phase (days one to five). Total (p = 0.02) and low-frequency (p = 0.009) BPV spectral power were significantly decreased during the acute phase of concussion. BRS down-sequence (p = 0.036) and up-sequence (p = 0.05) were significantly increased in the acute phase of concussion, with a trend towards an increased BRS pooled (p = 0.06). Significant decreases in HRV were also found. Acute concussion resulted in altered BRS and BPV dynamics compared to baseline. These findings highlight objective physiological parameters that could aid concussion diagnosis and return-to-play protocols.

Can Multiple Object Tracking Predict Laparoscopic Surgical Skills?

OBJECTIVE: The purpose of this study was to examine the relationship between multiple object tracking (MOT) and simulated laparoscopic surgery skills. METHODS: A total of 29 second-year medical students were recruited for this study. The participants completed 3 rounds of a three-dimensional MOT and a simulated laparoscopic surgery task. Averages of the performance on the tasks were calculated. Descriptive variables (i.e., age, hours of sleep, caffeine, and video game use) were measured via questionnaires. Data were analyzed using hierarchical regression models with surgical performance as the outcome variable. Predictor variable was the multiple objects tracking score and the descriptive variables. RESULTS: The regression models revealed a significant prediction of simulated laparoscopic surgical skills by the multiple objects tracking score. In particular, 29% of the variance of time to completion and 28% of the average surgical arm movement were explained. In both regressions, the MOT score was the only significant predictor. CONCLUSION: This study demonstrates the potential implications of perceptual-cognitive training for future surgeons. Along with motor skill practice, MOT may aid to better prepare health care professionals for the complex cognitive demands of surgery.

Factorial validity and gender invariance of the center for epidemiological studies depression in cardiac rehabilitation patients.

PURPOSE: To find a best-fitting factor structure of the Center for Epidemiological Studies Depression (CES-D) and test whether this structure is invariant across gender in a cardiac rehabilitation population. METHODS: We examined the data from 920 participants of a cardiac rehabilitation exercise program. Fourteen confirmatory factor analyses were conducted to examine existing factor solutions from the literature. The best-fitting model was tested for invariance across gender. RESULTS: The data fit best to a 3-factor solution, which has 14 items and 3 factors (ie, somatic symptoms, negative affect, and anhedonia). The goodness-of-fit indices showed an acceptable fit. The invariance analysis revealed that the factor structure is equivalent across gender. CONCLUSIONS: While a fitting factor solution was found, rehabilitation practitioners and researchers need to be aware of the psychometrical shortcomings of the CES-D and consider using other scales as alternative measures of depressive symptoms.

Exploring a model linking social physique anxiety, drive for muscularity, drive for thinness and self-esteem among adolescent boys and girls.

This study examined gender differences on body image measures, and tested a model where self-esteem influences social physique anxiety (SPA), which in turn influences drive for muscularity and drive for thinness in a sample of adolescents (N=329; 58% boys). Multi-group invariance analyses indicated that the measurement and structural models were partially invariant for boys and girls, allowing for gender comparisons. Results indicated that boys reported significantly lower drive for thinness and SPA, and higher drive for muscularity and self-esteem compared to girls. The measurement and structural models were an adequate fit for the total sample. Findings supported the proposed sequence in which self-esteem significantly influenced SPA, and SPA significantly influenced the drives for muscularity and thinness. Interventions aimed at decreasing SPA, by promoting self-esteem, may be helpful in decreasing adolescent boys' and girls' drive for muscularity and thinness.

Effect of sugar-free Red Bull energy drink on high-intensity run time-to-exhaustion in young adults.

Consuming sugar-free Red Bull energy drink before exercise has become increasingly popular among exercising individuals. The main purported active ingredient in sugar-free Red Bull is caffeine, which has been shown to increase aerobic exercise performance. The purpose of this study was to determine the effects of sugar-free Red Bull energy drink on high-intensity run time-to-exhaustion in young adults. Physically active university students (n = 17, 9 men, 8 woman; 21 +/- 4 years, 73.4 +/- 3.1 kg, 175.1 +/- 3.2 cm) participated in a double-blind, crossover, repeated-measures study where they were randomized to supplement with sugar-free Red Bull (2 mg x kg(-1) body mass caffeine or approximately 147 mg caffeine; 4 kcal/250 mL) and noncaffeinated, sugar-free placebo (lemon-lime flavored soft drink, tonic water, lime juice; 4 kcal/250 mL) separated by 7 days. Exercise capacity was assessed by a run time-to-exhaustion test at 80% Vo2max, perceived exertion was assessed immediately after exercise, and blood lactate was measured before and after exercise. There were no differences in run time-to-exhaustion (Red Bull: 12.6 +/- 3.8 minutes, placebo: 11.8 +/- 3.4 minutes), perceived exertion (Red Bull: 17.1 +/- 2.0, placebo: 16.6 +/- 1.8), or blood lactate between groups. In conclusion, sugar-free Red Bull energy drink did not influence high-intensity run time-to-exhaustion in young adults.

Comparison of two nutrition education approaches to reduce dietary fat intake and serum lipids reveals registered dietitians are effective at disseminating information regardless of the educational approach.

OBJECTIVE: The purpose of this study was to compare an educational approach based on the Stages of Change Model with usual care education in reducing dietary fat intake and serum lipids in individuals with hyperlipidemia. DESIGN: A 40-week randomized control study was conducted. Four education sessions were provided on an outpatient basis during a 1-month period with follow-up every 6 weeks. PARTICIPANTS: The sample consisted of 141 men and women with hyperlipidemia (mean age 50+/-11 years and a mean body mass index of 30+/-6) randomly assigned to one of two education interventions. INTERVENTION: The stages of change group was provided with tailored dietary activities based on their readiness to change to reduce dietary fat intake. Dietary information and activities for the usual care program were developed for those individuals ready to make a change in their diets. MAIN OUTCOME MEASURES: Serum lipids, anthropometric measures, readiness to change, dietary intake, and exercise data were assessed at baseline, 4, 16, 28, and 40 weeks. STATISTICAL ANALYSES: A repeated measures analysis of variance was used to compare differences between groups across time. RESULTS: Total cholesterol, low-density lipoprotein cholesterol, and body weight decreased significantly at 4 weeks (P<0.05) for both groups and were sustained over time, with no differences between the groups. CONCLUSIONS: The stages of change education approach was not more effective than the usual care education approach in decreasing dietary fat intake and serum lipids in a classroom setting.

Dietary supplement use in adolescents.

PURPOSE OF REVIEW: As prevalence rates of dietary supplement use are observed to be increasing in adolescents and the population in general, questions need to be asked about the efficacy, motivations, and consequences of such usage. Focusing mainly on individuals between the ages of 12 to 19 (adolescents) this review will highlight current prevalence rates, types of supplements being consumed, reasons for consumption, and concerns regarding physiological, psychological, knowledge transfer, and regulatory aspects of supplement use. RECENT FINDINGS: Studies have indicated the prevalence of dietary supplement usage by adolescents range from approximately 10% to as high as 74%. Some of the highest rates of usage appear in chronically ill adolescents. Multivitamin and mineral preparations are the most common supplements being consumed; however, many studies indicate that adolescents are using other substances like creatine, herbals, or protein supplements. Some of the most appealing supplements among this age group are those that enhance athletic performance or physical appearance. Recent literature suggests three key moderating factors for supplement use in adolescents: health status, gender, and level of physical activity involvement. SUMMARY: As the dietary supplement industry is now a multi-billion dollar industry, there is growing pressure, and a subsequent need for research to establish the efficacy and safety of these products particularly for adolescent users. The psychological and educational components of such use cannot be ignored as they play an equally important role in the health and safety of adolescents.

A look at nutritional supplement use in adolescents.

PURPOSE: To examine the use of nutritional supplements by adolescents. Supplements examined were those purported to influence performance and body mass. METHODS: 333 adolescents (190 male, 139 female, 4 nonrespondents) between the ages of 13 and 19 years, from a midwestern province in Canada, completed a pencil-and-paper survey. Participants, who were enrolled in health and wellness/physical education classes, were requested to provide information about current and potential use of 10 readily available nutritional supplements, as well as their knowledge of these products as potentially performance enhancing. Differences in use, potential use, and knowledge, as a function of gender, age, and level of physical activity were examined using Chi-square analyses and ANOVA techniques. RESULTS: The most popular dietary aids were multivitamin/mineral preparations (42.5%). More adolescent males than females reported that they currently used both creatine and diuretics. Female respondents indicated that they would consume herbal weight control products significantly more than males. Older students and students reporting high levels of physical activity were significantly more likely to be supplementing with creatine and protein. Males were more likely than females to believe that creatine and androsterone were performance-enhancing agents. Individuals highly involved in physical activity tended to believe that multivitamins, creatine, L-carnitine, energizers, and protein supplements could enhance their performance. CONCLUSIONS: This study highlights the fact that many nutritional supplements fall within the spectrum of adolescent use, and that this use may be driven by misguided beliefs in their performance-enhancing abilities. Groups at particular risk, such as individuals involved in physical activity to a high degree, are highlighted and the need for gender-specific information is suggested.

Factors influencing enrollment in a cardiac rehabilitation exercise program.

In order to encourage enrollment in cardiac rehabilitation exercise programs, it is essential to understand the perceptions of both enrollers and non-enrollers. Factors influencing enrollment in a cardiac rehabilitation exercise program in a northern centre in Canada servicing a large rural area were examined. Letters of invitation to participate in the program were sent to 30 cardiac patients who had enrolled in the program as well as to 30 patients who had met medical clearance criteria and were eligible to participate but who had not enrolled. Responses were obtained from 20 enrollers and 9 non-enrollers. Participants completed a questionnaire developed by the investigators and then took part in a semi-structured interview. Both quantitative and qualitative data revealed physician recommendation as an influential factor for enrollment in the cardiac rehabilitation exercise program. Encouragement from family and friends and access to transportation also emerged as important factors for enrollers. The results of the study may assist health care professionals to increase enrollment in cardiac rehabilitation programs through education and provision of encouragement by appropriate individuals.