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Sex Differences on Autonomic Modulation in Response to Weight Machines
It has been suggested that an acute bout of resistance exercise reduces vagal modulation for at least 30 minutes. PURPOSE: We sought to evaluate how autonomic modulation during recovery from an acute bout of resistance exercise differs between the sexes. METHODS: Forty-six volunteers (men: 25; women: 21) underwent an acute bout of resistance exercise consisting of 3 sets of 10 reps at 75% of 1-repetition maximum on the chest press, latissimus dorsi pulldown, leg press, leg curl and leg extension, and a Control. Heart rate variability (HRV) was assessed at Rest, 15-20 minutes (Rec1), and 25-30 minutes (Rec2) during recovery. Vagal modulation was assessed using HRV and included logarithmically (ln) transformed high-frequency power (lnHF), as well as the root mean square of successive differences (lnRMSSD). Sympathovagal balance was assessed using low frequency/high frequency ratio (lnLF/HF ratio). Two-way repeated measures ANOVAs were used to evaluate differences between sexes across time. RESULTS: There were no two-way interactions (sex by time) of vagal modulation or sympathovagal balance. There was a significant main effect of time for lnHF such that both recovery time points were higher compared to Rest. There were also significant main effects of time for lnRMSSD, and lnLF/HF ratio such that Rest was significantly lower than Rec1 and Rec2. CONCLUSIONS: These data suggest that an acute bout of weight machine exercise results in the same vagal modulation and sympathovagal balance between men and women. Keywords: parasympathetic, vagal, resistance exercise
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Heavy Rope Exercise on Hemodynamics and Arterial Stiffness in Resistance-Trained IndividualsPROBLEM: Heavy rope exercise may increase muscle hypertrophy and maximal strength. However, the effects of heavy rope exercise on cardiovascular hemodynamics and arterial stiffness is unknown. Therefore, the purpose of the present study was to evaluate the effects of heavy rope exercise on cardiovascular hemodynamics and arterial stiffness. METHODS: Fifteen resistance-trained individuals volunteered to participate. Cardiovascular hemodynamics and arterial stiffness were collected at rest, 15 (Rec1), 30 (Rec2) and 60 (Rec3) minutes after an acute bout of heavy rope exercise. Cardiovascular hemodynamics included heart rate (HR), mean arterial pressure (MAP), cardiac output (CO), stroke volume (SV), and total peripheral resistance (TPR). Arterial stiffness was measured via carotid-femoral pulse wave velocity (cf-PWV). The acute heavy rope exercise consisted of six, 15-second exercise bouts, using a double wave pattern, separated by 30-seconds of passive recovery intervals; the pace of the exercise was set at 180bpm. RESULTS: There were no significant main effects of time on MAP or SV. There were significant (p=0.0001) main effects of time for HR, CO, TPR. HR and CO were elevated at all times post-exercise, and was higher at Rec1 compared to Rec2, and Rec3, and was lower at Rec3 compared to Rec1 and Rec2. TPR was reduced at Rec1, Rec2 and Rec3 compared to rest. There were also significant main effect of time for cf-PWV such that it was attenuated at Rec3 compared to Rec1 and Rec2. CONCLUSIONS: These data demonstrate that acute heavy rope exercise increases cardiovascular workload for at least 30 minutes. |
Cardiovasucalr Stress Response & Esports
Esports is quickly growing into mainstream sports media with having one of the fastest growing fan bases in professional sports. There are currently over thirty-four million core gamers in the United States, and they are playing for an average of twenty-two hours a week. This study examines how video gaming elicits stress response in a person and its long-term effects on the cardiovascular system. Participants include college students who will be observed during game play using a polar heart rate monitor, polar watch, EKG machine and salivary cortisol samples. The objective of the study is to examine variations within HR and BP between rest, game play, and physical exercise paired with game play. With this study we will be able to conclude if there is a link between prolonged exposure to video games and subsequent increased heart rate and stress levels. Findings and implications will be discussed.
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Exploring Sex Differences on Arterial Stiffness in Response to Heavy Rope Exercise
High-intensity heavy rope exercise (HI-HRE) improves muscular strength and increases power. To date, no studies have examined the effects of HI-HRE on arterial stiffness, carotid artery compliance or differences among these measurements between sexes. PURPOSE: To evaluate sex differences on aortic and carotid arterial stiffness (CAS), and carotid artery compliance, following an acute bout of HI-HRE. METHODS: Twenty-seven resistance-trained individuals (men: n=14, women: n=13) volunteered for the study. Aortic arterial stiffness was measured via carotid-femoral pulse wave velocity (cf-PWV). CAS, measured via beta stiffness, and carotid artery compliance, were collected via Doppler ultrasound. All measurements were collected at Rest, 15 (Rec1), 30 (Rec2), and 60 (Rec3) minutes following HI-HRE. The HI-HRE intervention consisted of six 15-second exercise bouts using a double wave pattern set at a pace of 180bpm, with 30-second seated recovery intervals between bouts. RESULTS: There were no significant sex by time interactions for cf-PWV, or beta stiffness. For carotid artery compliance there was a significant sex by time interaction (p=0.05). At Rest, women had elevated carotid artery compliance compared to men. At Rec1, women had a larger decrease in carotid artery compliance than men. Women during Rec2 experienced a significant reduction in carotid artery compliance compared to rest, whereas men increased. During Rec3, women had higher carotid artery compliance compared to men. CONCLUSIONS: These data suggest no difference in aortic or CAS between sexes following an acute bout of HI-HRE. Women had greater changes in carotid artery compliance between time points compared to men.
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Effect of Heat on Serum and Plasma Brain-derived Neurotrophic Factor During Aerobic Exercise
Purpose: The purpose of this study was to examine temperature related effects on BDNF during aerobic exercise in different environmental conditions along with differences between serum and plasma BDNF. Methods: Six recreationally active college aged men (26 3 years) completed a VO2max test (48.6 5.7 mL/kg/min) and performed experimental trials in 35C at 45% humidity (HT/MH) and 22C at 45% humidity (MT/MH). During each trial, participants cycled for 60-minutes at 60% of VO2max, rested for 15-minutes, cycled until exhaustion at 90% VO2max, then recovered for 60-minutes. Blood was obtained before exercise (PRE), after 60 minutes of cycling (60), after the TTE (90), and after recovery (REC). Serum and plasma BDNF were assessed via ELISA, while data was analyzed using a mixed model regression, with significance defined as 0.05. Results: There was no significant condition by time interaction (F = 0.602, p = 0.618) nor main effect of condition (F = 1.792, p = 0.189) or time (F = 1.949, p = 0.139) for serum BDNF concentrations. There was also no significant condition by time interaction (F = 0.272, p = 0.845) nor main effect of condition (F = 0.415, p = 0.523) or time (F = 1.070, p = 0.373) for plasma BDNF concentrations. Conclusions: This data suggests high temperature does not have an effect on the BDNF response in serum or plasma concentrations. Nor does this study give evidence to an upregulation of BDNF concentrations due to aerobic exercise, though further work is warranted.
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Bench Press with Blood Flow Restriction on Autonomic Modulation
Traditional resistance exercise decreases vagal tone up to 30 minutes. This may not be true of resistance exercise with blood flow restriction (BFR), due to the low level of resistance that is utilized. The purpose of this research study was to evaluate autonomic modulation after resistance exercise with and without BFR in eleven young resistance-trained men. Autonomic modulation and sympathovagal balance were assessed at Rest, 15, and 25 minutes after low-load bench press with BFR (LL-BFR), traditional high-load bench press (HL), and a control. The two resistance exercise protocols were matched for volume. Autonomic modulation assessments were expressed as natural logarithm (ln), and included total power (lnTP), low-frequency power (lnLF), high-frequency power lnHF), sympathovagal balance (lnLF/HF ratio), root mean square of the successive differences (lnRMSSD), and the proportion of intervals differing by >50 ms from the preceding intervals (lnPNN50). A repeated measures ANOVA was used to evaluate conditions across time on autonomic modulation. There were significant condition by time interactions for lnTP (p=0.015), lnHF (p=0.001), and lnRMSSD (p<0.001) such that they were reduced during recovery after LL-BFR and HL compared to Rest and Control. There were no interactions in the lnLF, lnLF/HF ratio, or lnPNN50. A main effect of time (p=0.004) for lnLF:HF ratio was demonstrated by significant augmentation post exercise compared to rest. These data suggest that LL-BFR and HL significantly reduce vagal modulation up to 30 minutes after resistance exercise. In addition, the vagal responses to HL compared to LL-BFR were similar when exercise volume was matched.
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Brain Derived Neurotropic Factor Response to Aerobic Exercise in the Cold
PURPOSE: To examine changes in brain derived neurotropic factor (BDNF) concentration in both plasma and serum following exercise in the cold. METHODS: Six recreationally active men (26±3 yrs; 180.3±5.8 cm; 85.3±8.4 kg; 48.6±5.7 ml·kg−1·min−1) completed an exercise protocol under two conditions: moderate temperature (MT; 23°C/45%RH) and low temperature (LT; 5°C). The protocol consisted of a 60-minute cycling trial at 60% VO2max, a 15-minute rest, and a time-to-exhaustion trial at 90% VO2max (TTE). Blood was collected before (T1) and after (T2) the 60-minute trial, immediately after TTE (T3), and one hour post-TTE. Plasma and serum concentrations of BDNF were measured via ELISA. Changes were analyzed using separate condition by time mixed-model regression for each dependent variable. RESULTS: No significant condition × time interaction (F =1.626, p =0.201) or main effect of time (F =0.626, p=0.603) was observed for changes in serum BDNF concentrations; however, a significant main effect of condition (F=7.685, p = 0.009) was observed. When collapsed across time, serum BDNF concentration was lower during LT (2718.8 1172.2 pg/mL) compared to MT (7240.5 1134.2 pg/mL; p =0.009). No significant condition × time interaction (F =0.117, p =0.950), main effect of time (F =0.511, p =0.677) nor main effect of condition (F =0.000, p =0.988) was observed for changes in plasma BDNF concentrations. CONCLUSIONS: The results of this study suggest that exercise in a cold environment blunts serum BDNF concentration. However, plasma concentrations of BDNF were not affected by environmental condition nor exercise.
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