31 170 Board #8 May 29 9:30 AM - 11:00 AM EffectsofHemodynamicresponsesand Vascular Endothelial Function toBloodFlowRestrictionExercise Training Yan Zhao 1 , Aicui Lin 2 , Andong Chen 1 , Beibei Lu 1 . 1 Nanjing Sport Institute, Nanjing, China. 2 Nanjing First Hospital, Nanjing, China. Email: zynj77@163.com (No relationships reported) PURPOSE: The study aimed to compare hemodynamic responses and vascular endothelial function after 8 weeks resistance exercise with different blood flow restriction (BFR) in healthy adults. METHODS: Twenty-four participants (men 20.63±0.88 yr) were randomly assigned to three groups: resistance exercise without occlusion cuff (CON), resistance exercise with occlusion cuff pressure set at 65% resting systolic blood pressure (BFR-L) and resistance exercise with occlusion cuff pressure set at 130% resting systolic blood pressure (BFR-H). Each subject underwent five bouts of 1-minute 30%1RM resistance exercise with 2-min interval, 5 times a week for 8 weeks. Left ventricular fractional shortening (FS), left ventricular ejection fraction (LVEF), velocity, stroke volume (SV) resistance index (RI), Vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor (VEGF-R) and interleukin-6 (IL-6) were measured. RESULTS: 1.After 8 weeks,compared with AC in BFR-H group (94.42±20.99), AC in the CON group (106.13 ±18.86) and BFR-L group (108.08±19.22) significantly increased (p<0.05). 2. After 8 weeks, SBP was increased in the BFR-L group (3.37±0.674mmHg), BFR- H group(4.50±1.21mmHg ) and in the CON group (-6.37± -1.02mmHg). Exercise immediately after 8 weeks, DBP decreased in the BFR-H group (6.44±0.305mmHg) and the CON group (4.25±0.281mmHg), and the difference was statistically significant (p < 0.05).3. After 8-week training, compared with the expression of VEGF-R and IL-6 in CON group (641.23±12.68pg/ml,7.00±0.76 pg/ml), their expression in the BFR-L group(711.12±16.88pg/ml, 7.39±0.51pg/ml) and BFR-H group (703.63±15.49 pg/ml, 11.16±0.82pg/ml) significantly increased (p<0.05). CONCLUSIONS: BFR-L is beneficial to the improvement of aortic compliance. BFR-L and BFR-H all can cause reduction of DBP after exercise, which can be related to increased secretion of local VEGF and VEGF-R, causing angiogenesis and reducing peripheral resistance. 171 Board #9 May 29 9:30 AM - 11:00 AM Comparing Total Hemoglobin Mass Between Selected NCAA Division I Athletes And Recreationally Active Students Sewan Kim, Jesse A. Goodrich, William C. Byrnes, FACSM. University Colorado Boulder, Boulder, CO. (Sponsor: William C. Byrnes, FACSM) (No relationships reported) Total hemoglobin mass (tHb) is linearly related to total body mass, however, whether this relationship is altered by lean tissue mass, training or sex remains controversial. PURPOSE: To investigate if lean mass is a more appropriate determinant of tHb compared to body mass across NCAA DI athletes and controls. We will also determine if this relationship is altered by sex and/or training status. METHODS: Nordic (6F & 6M) and alpine (5M) skiers, football players (7M) and recreationally active student controls (9F & 10M) from the University of Colorado Boulder participated. The optimized carbon monoxide rebreathing procedure was used to determine tHb. Body composition was determined via DXA. Since female athletes were not present in all groups, statistical analyses were performed for males across all groups and a separate comparison was made between female nordic skiers and control groups. RESULTS: The overall correlations of tHb with body mass or lean tissue mass were significant (R 2 = 0.73 & R 2 = 0.88), but the positive relationship was stronger when using lean mass (p<0.001). For males, body mass and lean tissue mass were greater in football with no significant differences between any other group. Football had a greater tHb compared to control and alpine (1168.7 ± 126.9 vs. 925.9 ± 123.0 & 936.8 ± 151.9 g), but was not different than nordic (1052.5 ± 166.7 g). Nordic tHb was greater than control, but not different from alpine. When tHb was normalized using body mass and lean mass, nordic (14.5 ± 1.5 & 16.5 ± 1.2 g/kg) was greater than football (10.4 ± 0.9 & 14.4 ± 1.5 g/kg), alpine (11.6 ± 1.1 & 14.2 ± 0.6 g/kg) and control (11.8 ± 0.6 & 14.6 ± 0.8 g/kg) groups while no differences between any other groups were found. For females, body mass, lean tissue mass and tHB (656.4 ± 72.9 vs. 566.1 ± 66.0 g) were not different between nordic and control. When tHb was normalized using body mass, nordic (11.3 ± 0.7 g/kg) was greater than control (9.5 ± 1.0 g/kg), but when tHB was normalized using lean mass there was no difference (14.5 ± 1.1 vs. 13.8 ± 1.4 g/kg). CONCLUSION: Lean tissue mass explains a greater amount of variability in tHB compared to total body mass. In males, to examine the effect of endurance training on tHb, it is more appropriate to normalize by lean mass. Additional research is needed when comparing the effects of endurance training between female groups. 172 Board #10 May 29 9:30 AM - 11:00 AM Observation Of Heart Rate Variability Response To Collegiate Esports Tournament Gunner B. Rhoden, Silvio P. Valladao, Thomas Andre, Damon Cox. University of Mississippi, University, MS. (No relationships reported) OBSERVATION OF HEART RATE VARIABILITY RESPONSE TO COLLEGIATE ESPORTS TOURNAMENT G.B. Rhoden, S. Valladao, T.L. Andre, D. Cox. The University of Mississippi, Oxford, MS 1 Heart rate variability (HrV) derives from the intricate relationship of sympathetic and parasympathetic autonomic regulation of heart rate. HrV has been utilized as a marker of stress and recovery in traditional sports, however, to date no investigations examined the HrV response to esports. PURPOSE: To determine the HrV response during a competitive live esports tournament in collegiate club esport competitors. METHODS: Male members of the Ole Miss esports team (n=14; age = 19.8±1.0 years; BMI = 24.1±5.5; esport mean hours per week = 18.9±11.6) participated in the study during a live esports tournament. A pre-HrV and post-HrV (5-minutes each) measures were collected using a Polar H10 HR monitor with the Elite HrV mobile app while seated. Participants were seated for 5 minutes before obtaining pre- and post-HrV measures. For during competition HrV measure, recordings for HrV began immediately prior to their esport matches and ended immediately post while remaining seated. For the statistical analyses, One-Way Analysis of Variance (ANOVA) was used for RMSSD, ln(RMSSD), and R-R intervals. Tukey’s post hoc test were used when necessary. Paired-samples t-test were utilized for LF:HF ratio and HF. Results were considered significant at p ≤ 0.05. Results are reported as mean ± standard deviation. RESULTS: R-R intervals during were significantly lower than pre- and post- (pre: 643.64ms ± 138.54ms; during: 465.71ms ± 68.99ms; post: 616.07ms ± 109.98ms, p = 0.002). HF post competition was significantly decreased compared to pre (325.83ms 2 ± 341.81ms 2 vs. 494.55m 2 ± 526.84ms 2 ; p = 0.046). No significant differences were found for RMSSD (pre: 25.67ms ± 17.48ms; during: 15.50ms ± 12.34ms; post: 23.72ms ± 18.07ms; p = 0.223), ln(RMSSD) (pre: 3.00ms ± 0.77ms; during: 2.51ms ± 0.69ms; post: 2.86ms ± 0.90m; p = 0.249), or pre and post LF:HF ratio (pre: 4.47 ± 2.96 vs. post: 5.54 ± 3.62; p = 0.260). CONCLUSION: This is the first investigation to observe the HrV response to a live esport competition. Future investigations should examine differences between esport games and time durations. 173 Board #11 May 29 9:30 AM - 11:00 AM One-Year Changes in Cardiovascular Risk Markers in Police Officers Steven E. Martin, Danielle Kravits, Kory Sealy, Karina Wilson, Jason R. Lytle, Sean T. Stanelle, John S. Green, FACSM, Stephen F. Crouse, FACSM. Texas A&M University, College Station, TX. (Sponsor: Stephen F. Crouse, FACSM) (No relationships reported) PURPOSE: The present study retrospectively examined one-year changes in certain traditional and non-traditional cardiovascular disease (CVD) risk markers in police officers (n = 84). Subjects were full time police officers employed by a moderate-to-large municipality. Copyright © 2019 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.