RESUMEN
Contact-sports can elicit concussions, which impacts autonomic function, as well as elicit repetitive head trauma, where autonomic function has not yet been assessed. The purpose of this study was to determine if differences in autonomic function exist among three groups (CTRL: healthy non-contact-sport participant, RHT: repetitive head trauma contact-sport participant, CONC: previous concussion). Forty participants (16 men and 24 women), aged 18-37 (22 ± 3), participated in the study. Participants were grouped based on their sport and concussion history (CTRL, RHT, and CONC). Body composition was measured via air displacement plethysmography. Prior to testing, participants were outfitted with equipment to evaluate heart rate, blood pressure, and cerebral-artery blood flow velocity (CBFv). The participant performed against three stimuli: deep breathing, Valsalva maneuver, and a 70° head-up tilt test. Following autonomic function testing, a YMCA submaximal cycle test was performed. All group comparisons were analyzed using a one-way ANOVA and all data are presented as means ± standard deviation. The results of this study indicated that the groups did not differ in respiratory sinus arrhythmia (CTRL: 22 ± 6 bpm, RHT: 21 ± 8 bpm, CONC: 19 ± 7 bpm, p = 0.471), Valsalva ratio (CTRL: 2.19 ± 0.39, RHT: 2.09 ± 0.37, CONC: 2.00 ± 0.47, p = 0.519), CBFv (CTRL: 47.74 ± 25.28 cm/s, RHT: 40.99 ± 10.93 cm/s, CONC: 43.97 ± 17.55 cm/s, p = 0.657), or tilt time (CTRL: 806.09 ± 368.37 sec, RHT: 943.07 ± 339.54 sec, CONC: 978.40 ± 387.98 sec, p = 0.479). However, CONC (113.24 ± 11.64 mmHg) had a significantly higher mean systolic blood pressure during the tilt test than CTRL (102.66 ± 7.79 mmHg, p = 0.026), while RHT (107.9 ± 9.0 mmHg) was not significantly different than CTRL (p = 0.39) or CONC (p = 0.319). The results of this study are the first step in determining if long-lasting deficits to the autonomic nervous system occur following a diagnosis of concussion. However, concussions do not seem to have lasting effects on autonomic function. Overwhelmingly, dysautonomia is not present during chronic recovery from concussions or in individuals with RHT from contact-sports. In the future, sex should be considered as a variable.
RESUMEN
The purpose of this study was to determine sex differences in the contribution of sensory nerves to rapid cutaneous thermal hyperemia. Healthy young females (n = 15, tested during both the early follicular (EF) and the mid-luteal (ML) phase of the menstrual cycle) and males (n = 15) had a 4 cm2 area of skin on one forearm and one leg treated with a eutectic mixture of local anesthetic (EMLA). EMLA sites, along with corresponding control sites, were instrumented with laser Doppler flowmetry probes and local skin heaters. Baseline (33 °C), rapid and sustained vasodilation (42 °C), and maximal vasodilation (44 °C) skin blood flow data were obtained and expressed as a percentage of maximal cutaneous vascular conductance (%CVCmax). Contribution of sensory nerve involvement was determined by comparing the EMLA site to its matched control site utilizing the formula [(% CVCmax control - % CVCmax treatment) / % CVCmax control] × 100. The contribution of sensory nerves to rapid cutaneous thermal hyperemia in the forearm was 24 ± 18 %CVCmax in males, 41 ± 17 %CVCmax in ML females (p = 0.02 vs. males), and 35 ± 17 %CVCmax in EF females (p > 0.05 vs. males). In the leg, the contribution of sensory nerves was 16 ± 15 %CVCmax in males, 34 ± 17 %CVCmax for ML females (p = 0.02 vs. males), and 28 ± 21 %CVCmax in EF females (p > 0.05 vs. males). ML females exhibited a greater contribution of sensory nerves to rapid cutaneous thermal hyperemia in the forearm and leg, possibly attributed to elevated reproductive hormones during the ML phase.
RESUMEN
Body mass index (BMI) has been used for years by clinicians to approximate total body fat. However, the body adiposity index (BAI), body adiposity index from the FELS longitudinal study (BAIFELS), and an equation developed by Deurenberg et al. (BFD) were created recently to offset BMI's limitations and accurately estimate percent body fat (%BF). The prevalence of overweight and obese Caucasian men is increasing in the United States; currently, there is no established way to quickly and accurately predict their %BF. PURPOSE: To compare the existing %BF equations (BAI, BAIFELS, and BFD) to measured %BF via air displacement plethysmography (ADP) in order to determine the most accurate way to predict %BF in overweight and obese Caucasian men. METHODS: Four hundred and fifty-two Caucasian men aged from 18 to 76, with a BMI of 25.0 to 42.4 kg/m2, participated in this study. Height, weight, waist circumference, hip circumference, and body composition using ADP were measured on each participant. These measurements were inserted into the three equations to determine any differences between the equations and the actual %BF measured by ADP. RESULTS: Differences in %BF between ADP and the BAI (p < 0.001) and ADP and the BAIFELS (p < 0.001) were discovered. While no differences (p = 1.00) between ADP and BFD existed. CONCLUSION: In a population of overweight and obese Caucasian adults from the United States, the BAI and BAIFELS are not appropriate to predict %BF while the BFD prediction equation proved worthy of consideration.
