BioSteel High Performance Sports Drink Improves Exercise Performance Following a Simulated Hockey Game

INTRODUCTION: BioSteel High Performance Sports Drink (BioSteel) is one of the most popular sports supplements consumed by professional and amateur athletes. BioSteel Inc® claims that consumption of BioSteel before and during exercise will result in “enhanced energy while delaying the onset of muscular and mental fatigue”. PURPOSE: Assess the efficacy of BioSteel supplementation on anaerobic and aerobic exercise performance as well as sport-specific cognition throughout exercise. METHODS: Eleven exercise-trained men completed a simulated hockey game on a cycle ergometer under two experimental conditions: BioSteel and isoenergetic placebo. Measures of exercise performance and cognition were assessed before, throughout and after the game. RESULTS: When compared to placebo, BioSteel supplementation significantly improved mean power output and decreased time to complete a simulated overtime period as well as significantly enhanced selective attention following the third period. CONCLUSION: BioSteel consumption before and throughout a simulated hockey game improves exercise performance and potentially augments cognition

Autonomic Dysregulation in Adolescent Concussion Is Sex- and Posture-Dependent

Objective: To study autonomic responses to postural changes in concussed adolescents. The influence of sex was also studied. Design: Longitudinal cohort observational study. Participants: Concussed adolescents (CONC; n = 65; 26 male adolescents; age 15 ± 1 years, range = 12-18 years) and a control (CTRL) group of nonconcussed adolescents of similar age and sport (CTRL; n = 54; 29 male adolescents; age 14 ± 1 years, range = 12-18 years). Interventions: Concussed participants were monitored through 6 weekly visits throughout usual physician care. Control participants underwent 2 visits separated by at least 1 week to account for intrapersonal variation in testing measures. Main Outcome Measures: Heart rate variability as the root mean square of successive differences in R–R intervals (RMSSD), heart rate (HR), and blood pressure [mean arterial pressure (MAP) and diastolic blood pressure (DBP)] were measured in supine, sitting, and standing postures. Results: A mixed analysis of variance revealed a group 3 sex 3 posture interaction (P = 0.04) where seated values of RMSSD were less in concussed female participants versus control female participants (42 ± 4 vs 61 ± 7 ms; P = 0.01; Mann–Whitney rank test). Compared with CTRL, CONC exhibited increased pretesting seated DBP (69 ± 1 vs 74 ± 1 mm Hg; P\u3c 0.01), MAP (83 ± 1 vs 86 ± 1 mm Hg; P = 0.02), and baseline seated HR (72 ± 1 vs 77 ± 2 bpm; P = 0.03). Values of DBP (P = 0.03) and MAP (P, 0.01) improved at clinical discharge, whereas the RMSSD in female participants did not (P \u3e 0.5). Data are mean ± SEM. Conclusions: A modest reduction in female cardiac autonomic regulation was observed during seated postures. Alterations in seated concussed DBP and MAP, but not RMSSD, resolved at clinical discharge (median = 37 days). The results indicate that, in adolescents, concussion may impair cardiovagal function in a sex- and posture-dependent manner. The findings also suggest that BP metrics, but not RMSSD, are associated with clinical concussion recovery

Autonomic Dysregulation in Adolescent Concussion Is Sex- and Posture-Dependent

Objective: To study autonomic responses to postural changes in concussed adolescents. The influence of sex was also studied. Design: Longitudinal cohort observational study. Participants: Concussed adolescents (CONC; n = 65; 26 male adolescents; age 15 ± 1 years, range = 12-18 years) and a control (CTRL) group of nonconcussed adolescents of similar age and sport (CTRL; n = 54; 29 male adolescents; age 14 ± 1 years, range = 12-18 years). Interventions: Concussed participants were monitored through 6 weekly visits throughout usual physician care. Control participants underwent 2 visits separated by at least 1 week to account for intrapersonal variation in testing measures. Main Outcome Measures: Heart rate variability as the root mean square of successive differences in R–R intervals (RMSSD), heart rate (HR), and blood pressure [mean arterial pressure (MAP) and diastolic blood pressure (DBP)] were measured in supine, sitting, and standing postures. Results: A mixed analysis of variance revealed a group 3 sex 3 posture interaction (P = 0.04) where seated values of RMSSD were less in concussed female participants versus control female participants (42 ± 4 vs 61 ± 7 ms; P = 0.01; Mann–Whitney rank test). Compared with CTRL, CONC exhibited increased pretesting seated DBP (69 ± 1 vs 74 ± 1 mm Hg; P\u3c 0.01), MAP (83 ± 1 vs 86 ± 1 mm Hg; P = 0.02), and baseline seated HR (72 ± 1 vs 77 ± 2 bpm; P = 0.03). Values of DBP (P = 0.03) and MAP (P, 0.01) improved at clinical discharge, whereas the RMSSD in female participants did not (P \u3e 0.5). Data are mean ± SEM. Conclusions: A modest reduction in female cardiac autonomic regulation was observed during seated postures. Alterations in seated concussed DBP and MAP, but not RMSSD, resolved at clinical discharge (median = 37 days). The results indicate that, in adolescents, concussion may impair cardiovagal function in a sex- and posture-dependent manner. The findings also suggest that BP metrics, but not RMSSD, are associated with clinical concussion recovery

Impaired Dynamic Cerebral Autoregulation to Postural Stress Following Concussive Injuries in Adolescents

Concussions disproportionately affect adolescents and ongoing maturation places this population at increased risk for prolonged recovery and long-term impairments in neurologic functioning. Although cerebrovascular impairments are believed to contribute to concussion symptoms and recovery, little information exists regarding brain vasomotor control in adolescent concussion, particularly during rapid changes in blood pressure that demand a dynamic cerebral autoregulatory response. The current investigation tested the hypothesis that adolescent concussion is marked by impaired dynamic cerebral autoregulation (CA). Twenty-two adolescents diagnosed with a concussion (CONC; 13 females; 15 ± 1 years; 26 ± 20 days post-injury, SCAT3 symptom score = 12 ± 6) and twenty-seven healthy controls (CTRL; 15 females; 14 ± 2 years; SCAT3 symptom score = 6 ± 4) completed two repeated sit-to-stand trials. CONC were followed through their rehabilitation for up to 12-weeks. Arterial blood pressure (ABP), cerebral blood flow velocity (CBFV), end-tidal carbon dioxide partial pressure (PetCO2), and heart rate (HR) were measured continuously with finger photoplethysmography (Finapres Medical Systems BV), transcranial Doppler ultrasound (Multigon Industries), a gas analyzer (AD Instruments), and a standard 3-lead electrocardiogram (ECG), respectively. Furthermore, cardiac output (CO) was provided via the Model flow algorithm and cerebrovascular resistance (CVR) was calculated. The rate of the drop in CVR relative to the change in ABP provided the rate of regulation (RoR). The drop in ABP with standing was similar between CONC and CTRL (25 ± 8 vs. 24 ± 7 mmHg; p = 0.62) although the time to ABP nadir was longer in CONC compared with CTRL (7.2 ± 1.1 vs. 6.1 ± 1.3 sec; p = 0.002). Similarly, time to CBFV nadir was longer in CONC compared with CTRL (5.9 ± 1.4 vs. 4.4 ± 2.0 sec; p = 0.003). Compared to CTRL, RoR was reduced in CONC at study entry (0.21 ± 0.06 vs. 0.16 ± 0.04 sec−1; p = 0.005). However, at the time of CONC final visit (SCAT3 symptom score = 4 ± 5), RoR improved to levels similar to CTRL (0.20 ± 0.08 vs. 0.21 ± 0.06 sec−1; p = 0.55). During sitting and standing, CONC and CTRL had similar PetCO2. The change in heart rate with standing was similar between CONC and CTRL (30 ± 6 vs. 26 ± 9 bpm; p = 0.09) although the time to peak HR was longer in CONC compared with CTRL (10.8 ± 2.5 vs. 9.4 ± 2.0 sec; p = 0.004). Furthermore, a similar increase in CO was witnessed with standing in CONC and CTRL (1.4 ± 1.6 vs. 1.7 ± 0.7 L/min; p = 0.28). Impairments in dynamic CA are evident in adolescents following a concussive injury which recover in accordance with clinical symptoms. Therefore, RoR may aid decisions regarding diagnosis, rehabilitation, and recovery of adolescent concussion

Autonomic Dysregulation in Adolescent Concussion: Characterization and Temporal Resolution of Neurological Outcomes

Although incidence is at epidemic levels, objective indicators of neurologic damage in adolescent concussion remain poorly described. Autonomic markers such as heart rate variability (HRV) have provided equivocal results; however, these predominantly are made under conditions of minimal physiologic stress. The current investigation employs postural stressors to examine underlying neurological outcomes associated with acute concussion and clinical recovery to test the hypothesis that concussion impairs dynamic autonomic adjustments in adolescents. We examined concussed adolescents (CONC; n = 35; 14 males; age 15 ± 1 yrs, range = 12–18 yrs) for up to 6 weekly visits from diagnosis. A group of age and activity level-matched non-concussed adolescents (CTRL; n = 35; 19 males; age 14 ± 2 yrs, range = 12–18 yrs) formed the reference control. HRV (root mean square of successive differences in R-R intervals (RMSSD)) and heart rate were assessed during a sit-to-stand protocol (two trials of seated posture (three minutes), followed by two minutes of standing). Measurements were taken during the last minute of sitting and standing, the ten second period following the postural stress of standing, as well as the ten second period from maximum HR. While seated, RMSSD was lower in CONC (41 ± 24 msec) compared with CTRL (60 ± 40 msec; p \u3c 0.05). 31 patients provided weekly data until clinical discharge. Compared with the first visit (43 ± 25 msec), seated RMSSD in CONC increased (51 ± 36 msec; p = 0.05) at the time of clinical discharge. Upon standing (10 seconds following postural change to standing), RMSSD was lower in CONC versus CTRL (13 ± 7 vs. 18 ± 12 msec; p \u3c 0.05). Compared with the first visit, RMSSD following the induced postural stress did not improve in CONC over the six week recovery period. Following maximal HR, CTRL had increased RMSSD versus CONC (46 ± 30 vs. 34 ± 19 msec; p \u3c 0.05). Compared with CTRL, seated HR was higher in CONC. This tachycardia effect persisted throughout the sit-to-stand protocol (78 ± 12 vs. 72 ± 12 bpm; p \u3c 0.05) and was maintained until the time of clinical discharge (79 ± 13 vs. 72 ± 12 bpm; p \u3c 0.05). In adolescent concussion, autonomic cardiac impairment is demonstrated by reduced RMSSD in the seated position and throughout the adjustment period in response to postural stress. Further, seated HR is increased following acute concussion and remains elevated by the time of clinical discharge. Seated HRV, but not HR, recovered to levels seen in the control population within three to six weeks. Thus, cardiac adjustments to modest postural stress may represent a measurable neurological impairment in adolescent acute concussion which can be objectively monitored throughout clinical recovery

An Investigation of Dynamic Cerebral Autoregulation in Adolescent Concussion.

Purpose Although cerebrovascular impairments are believed to contribute to concussion symptoms, little information exists regarding brain vasomotor control in adolescent concussion, particularly autoregulatory control that forms a fundamental response mechanism during changes in blood pressure. This research tested the hypothesis that adolescent concussion is marked by impaired dynamic cerebral autoregulation. Methods Nineteen concussed adolescents (15 ± 2 yr, 13 females) and 18 healthy controls (15 ± 2 yr, 9 females) completed two sit-to-stand trials. Brachial artery blood pressure and cerebral blood flow velocity in the right middle cerebral artery were measured continuously. Dynamic rate of regulation was calculated as the rate of change in cerebrovascular resistance relative to the change in arterial blood pressure. The concussed adolescents were followed through their rehabilitation for up to 12 wk. Results At the first visit, the concussed adolescents demonstrated reduced rate of regulation compared with the healthy controls (0.12 ± 0.04 vs 0.19 ± 0.06 s, P ≤ 0.001). At the concussed adolescents final visit, after symptom resolution, the rate of regulation improved to levels that were not different from the healthy controls (n = 9; 0.15 ± 0.08 vs 0.19 ± 0.06 s, P= 0.06). Two distinct groups were observed at the final visit with some individuals experiencing recovery of dynamic cerebral autoregulation and others showing no marked change from the initial visit. Conclusion Adolescents demonstrate an impairment in dynamic cerebral autoregulation after concussion that improves along with clinical symptoms in some individuals and remains impaired in others despite symptom resolution

Concussion in Adolescents Impairs Heart Rate Response to Brief Handgrip Exercise

OBJECTIVE: Test the hypotheses that (1) concussion in adolescents impairs autonomic neural control of heart rate (HR), and (2) HR reactivity improves with symptom resolution. DESIGN: Observational, case-control. PARTICIPANTS: Nineteen concussed adolescents (8 female adolescents; age 15 ± 2 years) and 16 healthy controls (6 female adolescents, age 15 ± 2 years). INTERVENTION: All participants performed an isometric handgrip (IHG) at 30% maximum voluntary contraction lasting 30 seconds. Heart rate (electrocardiogram) and hemodynamic responses (photoplethysmographic Finometer) were recorded from 30 seconds of baseline and the last 10 seconds of handgrip. MAIN OUTCOME MEASURES: The HR response (ΔHR) at the onset of moderate-intensity IHG using a mixed 1-way analysis of variance. RESULTS: A group × time interaction (P \u3c 0.005) indicated that handgrip evoked a greater ΔHR among control participants (13 ± 10 beats/min) compared with concussed (6.4 ± 6.3 beats/min; group P = 0.63; time P \u3c 0.001; d = 0.77). CONCLUSION: These preliminary results suggest that a concussion impairs the ability to elevate HR at the exercise onset and, given the nature of the task, this could be interpreted to reflect reduced ability to withdraw cardiovagal control. Therefore, the data support the hypothesis of neural cardiac dysregulation in adolescents diagnosed with concussion. CLINICAL RELEVANCE: The IHG test could aid concussion diagnosis and support return-to-play decisions

Concussion Symptoms Predictive of Adolescent Sport-Related Concussion Injury

OBJECTIVE: To assess the predictive capability of the postconcussion symptom scale (PCSS) of the sport concussion assessment tool (SCAT) III to differentiate concussed and nonconcussed adolescents. DESIGN: Retrospective.Tertiary. PARTICIPANTS: Sixty-nine concussed (15.2 ± 1.6 years old) and 55 control (14.4 ± 1.7 years old) adolescents. INDEPENDENT VARIABLES: Postconcussion symptom scale. MAIN OUTCOME MEASURE: Two-proportion z-test determined differences in symptom endorsement between groups. To assess the predictive power of the PCSS, we trained an ensemble classifier composed of a forest of 1000 decision trees to classify subjects as concussed, or not concussed, based on PCSS responses. The initial classifier was trained on all 22-concussion symptoms addressed in the PCSS, whereas the second classifier removed concussion symptoms that were not statistically significant between groups. RESULTS: Concussion symptoms common between groups were trouble falling asleep, more emotional, irritability, sadness, and anxious. After removal, analysis of the second classifier indicated that the 5 leading feature rankings of symptoms were headache, head pressure, light sensitivity, noise sensitivity, and don\u27t feel right, which accounted for 52% of the variance between groups. CONCLUSIONS: Collectively, self-reported symptoms through the PCSS can differentiate concussed and nonconcussed adolescents. However, predictability for adolescent patients may be improved by removing emotional and sleep domain symptoms