1000 resultados para Frequência Cardíaca
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The hemodynamic effects of total intravenous anesthesia with propofol or propofol in combination with lidocaine were investigated in 12 dogs. In the P group (n=6), the dogs received a loading dose (LD) of 6mg kg-1 of propofol followed by a constant rate infusion (CRI) of 1.25mg kg-1 min-1. In the PL group (n=6), dogs received a LD of 6mg kg-1 of propofol and 1.5mg kg-1 of lidocaine followed by CRIs of 1.0mg kg-1 min-1 and 0.25mg kg-1 min-1 of propofol and lidocaine, respectively. The animals were instrumented for measurement of hemodynamic variables and bispectral index (BIS), recorded at 75, 90, 105 and 120 minutes during anesthesia. Cardiac index, stroke index, systolic, diastolic and mean arterial blood pressures were lower in the P group compared to the PL group (P<0.05). There were no significant differences between groups in heart rate, systemic vascular resistance index and BIS. Plasma concentrations of propofol were lower in group PL than in group P (medians of 5.7 to 6.1mg mL-1 in the P group versus 3.1 to 3.7mg mL-1 in the PL group). Measured lidocaine plasma concentrations (medians of 2.27 to 2.51mg mL-1) were in the range that result in analgesia and were below values that result in toxicity in dogs. The BIS values observed in the two groups of dogs were compatible with deep anesthesia (mean values of 43-46 and 45-49 in groups P and PL, respectively). Maintenance of deep anesthesia with lidocaine-propofol causes less cardiovascular depression than equipotent doses of propofol alone.
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INTRODUCTION: Resistance training (RT) has been widely used for older adults in order to minimize or reverse the deleterious effects of aging in the neuromuscular system. However, the potential benefits of RT on arterial blood pressure and heart rate at rest in older adults remain controversial. OBJECTIVE: To analyze the effect of eight weeks of RT on systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and heart rate (HR) in older women without hypertension. METHODS: Seventeen women (aged 66.0 ± 5.8 years) without previous experience in RT were randomly assigned to either a training (TG, n = 10) or control (CG, n = 7) groups. Hemodynamic parameters at rest were evaluated by auscultatory method (mercury sphygmomanometer) and HR monitor (Polar), before and after eight weeks of experimental period. RESULTS: Reductions attributable to RT were found only to SBP (-13.4 mmHg, p <0.01). Although significant reductions were observed for DBP and MBP, the analysis of covariance showed no interaction Group x Time significant. CONCLUSION: RT proved an effective training to promote adaptations in the cardiovascular system of older women without hypertension. Eight weeks of RT can significantly reduce SBP at rest in older women.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The aim of this study was to investigate the effects of three weeks of training with intensity monitored on the aerobic capacity of professional soccer players. Fourteen players, members of a first division Brazilian Championship team in 2010, aged 22.78 +/- 3.06 years were evaluated pre and post three weeks of training. The anaerobic threshold intensity LAn was determined by bi-segmented method, for this four submaximal efforts of 800 meters with intensities 10, 12, 14 and 16 km/h were applied. Thirty three training sessions were quantified in zones according to heart rate related to the LAn (FCLAn): Z1 - 10% below, Z2 - 90-100% and Z3 - above the FCLAn. During training participants remained 31.17 +/- 14.86%, 42.96% and 25.87 +/- 14.90 +/- 16.67% in Z1, Z2, and Z3 respectively. There were no significant differences in the LAn (pre = 13,29 +/- 0,71 km.h(-1); post = 12,85 +/- 0,90 km.h(-1)), perceived exertion (pre = 11,53 +/- 1,45 u.a; post = 11,23 +/- 1,53 u.a) and FCLAn (pre = 166,64 +/- 10,69 bpm; post = 174,50 +/- 10,89 bpm) between conditions before and after training, indicating that three weeks of training are insufficient to generate positive changes in soccer players LAn.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Introduction: The literature has shown that musical stimulation can influence the cardiovascular system, however, the neurophysiological aspects of this influence are not yet fully elucidated. Objective: This study describes the influence of music on the neurophysiological mechanisms in the human body, specifically the variable blood pressure, as well as the neural mechanisms of music processing. Methods: Searches were conducted in Medline, PEDro, Lilacs and SciELO using the intersection of the keyword “music” with the keyword descriptors “blood pressure” and “neurophysiology”. Results: There were selected 11 articles, which indicated that music interferes in some aspects of physiological variables. Conclusion: Studies have indicated that music interferes on the control of blood pressure, heart and respiratory rate, through possible involvement of limbic brain areas which modulate hypothalamic-pituitary functions. Further studies are needed in order to identify the mechanisms by which this influence occurs.
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The literature indicates stress as a response of the organism to a stimulation that requires enormous efforts to adapt to the changes in the environment and the body. When an individual is subjected to stress, the autonomic nervous system is triggered, the sympathetic pathway is activated, and the parasympathetic system is suppressed, which exerts several effects on the cardiovascular system and affects heart rate variability. This research aimed to conduct a literature review to find and analyze the studies that address clearly the implications of stress on heart rate variability. The methodology employed was an active search in the databases SciELO, PubMed and Lilacs. The results were five articles, most of which suggest a relationship between stress and heart rate variability. We observed that the majority of the studies indicated a strong association between stress and cardiac autonomic activity. The stress is present in the daily activities of the population, especially in labor. The subject is vast, however, were observed in the references the effects of stress on the body making it vulnerable to diseases. Thus, this information may contribute to the aid of preventive strategies against stress and diseases of the cardiovascular system.
Responses of the geometric indices of heart rate variability to the active orthostatic test in women
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OBJECTIVES: The effects of the orthostatic test on the cardiovascular system have been investigated, but there are no data on the behavior of the geometric indices of heart rate variability. We evaluated the effects of the active orthostatic test on the geometric indices of heart rate variability in women. METHOD: The study was performed on 12 healthy women between ages 18 and 30. For the analysis of heart rate variability, heart rate was recorded beat-to-beat. The RR intervals were transformed into geometric figures, and from these we calculated the triangular index, the triangular interpolation of RR intervals, the SD1, SD2 indexes and the SD1/SD2 ratio, which were obtained from the Poincaré plot. Visual analysis of the plot was also performed. For the test, participants quickly stood up from a seated position in 3 seconds or less, and remained standing still for 15 minutes. Heart rate variability samples were collected at four moments: rest, 0-5 minutes, 5-10 minutes and 10-15 minutes at standing position. RESULTS: The triangular index, the triangular interpolation of RR intervals, the SD1 and SD2 indices were reduced (p < 0.05) at 10-15 minutes after the volunteers stood up from seated position. The SD1/SD2 ratio was decreased at 0-15 minutes after the subjects changed from seated to orthostatic position.
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BACKGROUND: Previous studies suggested that some interactive video games induce cardiovascular responses. However, some different styles of video games have not been investigated. OBJECTIVE: We aimed to evaluate cardiovascular responses induced by video game boxing performance in healthy women. METHOD: We evaluated ten female sedentary volunteers, aged 20.9 ± 1.4 years, weight 58.7 ± 8.0 kg, height 163.2 ± 5.4cm. All subjects were weighed and measured. Their heart rate, blood pressure and lactate levels were recorded before and after video game performance. The volunteers played a Sony video game (Nintendo® Wii) by using the boxing method, in which all volunteers played for 10 minutes without interruption. At the end of the game the volunteers were reassessed using the same parameters mentioned above. RESULTS: At the end of the video game boxing performance we observed highly significant increases of lactate production (p < 0.0035) and the double product (heart rate vs. systolic blood pressure) was also higher (p < 0.0001). Both parameters indicate that the performance increased demands of the cardiovascular system. CONCLUSION: We conclude that a ten-minute video game boxing performance induces cardiovascular responses similar to aerobic exercise. This may be a practical form of exercise, but care should be exercised concerning subjects with cardiovascular disorders.
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INTRODUCTION: We aimed to evaluate the effects of musical auditory stimulation on cardiac autonomic regulation in subjects who enjoy and who do not enjoy the music. METHOD: The study was performed in young women (18-27 years old) divided in two groups (1) volunteers who enjoyed the music and (2) volunteers who did not enjoy the music. Linear indices of heart rate variability were analyzed in the time domain. The subjects were exposed to a musical piece (Pachelbel: Canon in D Major) during 10 minutes. Heart rate variability was analyzed at rest with no music and during musical auditory stimulation. RESULTS: In the group that enjoyed the music the standard deviation of normal-to-normal R-R intervals (SDNN) was significantly reduced during exposure to musical auditory stimulation. We found no significant changes for the other linear indices. The group composed of women who did not enjoy the music did not present significant cardiac autonomic responses during exposure to musical auditory stimulation. CONCLUSION: Women who enjoyed the music presented a significant cardiac autonomic response consisting of a reduction in heart rate variability induced by the musical auditory stimulation. Those who did not enjoy the musical piece presented no such response.