33 research outputs found

    Cardiovascular Responses To Postural Change And Aerobic Capacity In Middle-aged Men And Women Before And After Aerobic Physical Training

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    Objective: To compare the cardiovascular responses to passive postural maneuvers (tilt test) and the cardiorespiratory capacity in middle-aged men and women, before and after aerobic physical training. Methods: Seven men (44.6±2.1 years old) and seven women (51.7±4.8 years old) participated in aerobic physical training for 12 weeks. The tilt test protocol (five minutes supine, ten minutes tilted at 70° and five minutes supine) was followed, with arterial blood pressure and heart rate monitoring. A cycle ergometer protocol was used to measure cardiorespiratory capacity. Results: In the sedentary condition, men showed greater parasympathetic influence in heart rate control, as demonstrated by their higher RR interval (iRR) during the tilt test. After training, the iRR values became more similar in the two groups, although the women had higher iRR in the supine position and the men continued to present higher iRR under tilted conditions. The women's blood pressures continued to be higher after training, but heart rate tended to become similar in the two groups. The cardiorespiratory capacity patterns in the two groups were similar after training. Except for absolute heart rate values, for which there were no differences between the groups, the men's values were higher than those of the women for all other variables. It was also observed that, after the training, the women's blood pressures were significantly lower, even though their pressures remained higher than the men's. Conclusions: The training seemed to reduce the women's arterial blood pressure levels and improve both groups' cardiorespiratory capacity, but the men continued to present better performance than the women.125392400Pollock, M.L., Dawson, G.A., Physiologic responses of men 49 to 65 years of age to endurance training (1976) J Am Geriatr Soc, 24 (3), pp. 97-104Haddock, B.L., Marshak, H.P.H., Mason, J.J., Blix, G., The effect of hormone replacement therapy and exercise on cardiovascular disease risk factors in postmenopausal women (2000) Sports Med, 29 (1), pp. 39-49Liu, C.C., Kuo, T.B., Yang, C.C., Effects of estrogen on gender-related autonomic differences in humans (2003) Am J Physiol Heart Circ Physiol, 285 (5), pp. H2188-H2193Rosano, G.M., Vitale, C., Fini, M., Hormone replacement therapy and cardioprotection: What is good and what is bad for the cardiovascular system? (2006) Ann. N.Y. Acad Sci, 1092, pp. 341-348Ghorayeb N, Baptista CA, Dioguardi GS, Reginatto LE. Atividade física na mulher. Rev Soc Cardiol Est São Paulo, SOCESP.1996;6:540-2Kannel, W.B., Hjortland, M.C., McNamara, P.M., Gordon, T., Menopause and risk of cardiovascular disease: The Framingham study (1976) Ann Intern Med, 85 (4), pp. 447-452Tank, J., Does aging cause women to be more sympathetic than men? (2005) Hypertension, 45 (4), pp. 489-490Kuttenn, F., Gerson, M., Hormone replacement therapy of menopause, heart and blood vessels (2001) Arch Mal Coeur Vaiss, 94 (7), pp. 685-689Vanoli, E., De Ferrari, G.M., Stramba-Badiale, M., Hull Jr, S.S., Foreman, R.D., Schwartz, P.J., Vagal stimulation and prevention of sudden death in conscious dogs with a healed myocardial infarction (1991) Circ Res, 68 (5), pp. 1471-1481Smith, J.J., Kampine, J.P., (1990) Regulation of arterial blood pressure, , editores. Circulatory physiology, the essentials. 3aed. Baltimore: Williams &ampWilkins;Kuo, T.B., Lin, T., Yang, C.C., Li, C.L., Chen, C.F., Chou, P., Effect of aging on gender differences in neural control of heart rate (1999) Am J Physiol, 277 (6 PART 2), pp. H2233-H2239Evans, J.M., Ziegler, M.G., Patwardhan, A.R., Ott, J.B., Kim, C.S., Leonelli, F.M., Gender differences in autonomic cardiovascular regulation: Spectral, hormonal, and hemodynamic indexes (2001) J Appl Physiol, 91 (6), pp. 2611-2618Pikkujämsä, S.M., Mäkikallio, T.H., Airaksinen, K.E., Huikuri, H.V., Determinants and interindividual variation of R-R interval dynamics in healthy middle-aged subjects (2001) Am J Physiol Heart Circ Physiol, 280 (3), pp. H1400-H1406Neves, V.F., Silva de, S.M., Gallo Jr, L., Catai, A.M., Martins, L.E., Crescêncio, J.C., Autonomic modulation of heart rate of young and postmenopausal women undergoing estrogen therapy (2007) Braz J Med Biol Res, 40 (4), pp. 491-499(2005) ACSM's guidelines for exercise testing and prescription/ACSM, , American College of Sports Medicine, Philadelphia: Lippincott Williams & Wilkins;Maciel, B.C., Gallo Júnior, L., Marin Neto, J.A., Lima Filho, E.C., Terra Filho, J., Manço, J.C., Parasympathetic contribution to bradycardia induced by endurance training in man (1985) Cardiovasc Res, 19 (10), pp. 642-648Martinelli, F.S., (1996) Respostas da freqüência cardíaca e da pressão arterial sistêmica às manobras postural passiva e de valsalva, em indivíduos sedentários e atletas corredores de longa distância, , dissertação, Campinas: Unicamp;Goldsmith, R.L., Bigger Jr, J.T., Steinman, R.C., Fleiss, J.L., Comparison of 24-hour parasympathetic activity in endurance-trained and untrained young men (1992) J Am Coll. Cardiol, 20 (3), pp. 552-558Shin, K., Minamitani, H., Onishi, S., Yamazaki, H., Lee, M., Autonomic differences between athletes and nonathletes: Spectral analysis approach (1997) Med Sci Sports Exerc, 29 (11), pp. 1482-1490Seals, D.R., Taylor, J.A., Ng, A.V., Esler, M.D., Exercise and aging: Autonomic control of the circulation (1994) Med Sci Sports Exerc, 26 (5), pp. 568-576Chacon-Mikahil, M.P.T., (1998) Estudo da variabilidade da freqüência cardíaca nos domínios do tempo e da freqüência antes e após o treinamento aeróbio em homens de meia idade [tese], , Campinas: Unicamp;Laitinen, T., Niskanen, L., Geelen, G., Länsimies, E., Hartikainen, J., Age dependency of cardiovascular autonomic responses to head-up tilt test in healthy subjects (2004) J Appl Physiol, 96 (6), pp. 2333-2340Gordon, C.C., Chumlea, W.C., Roche, A.F., Stature, Recumbent Length, Weight (1988) Anthropometric standardizing reference manual, pp. 3-8. , Lohman TG et al, editores, Champaign, Illinois: Human Kinetics Books;Wasserman, K., Whipp, B.J., Koyl, S.N., Beaver, W.L., Anaerobic threshold and respiratory gas exchange during exercise (1973) J Appl Physiol, 35 (2), pp. 236-243Montano, N., Ruscone, T.G., Porta, A., Lombardi, F., Pagani, M., Malliani, A., Power spectrum analysis of heart rate variability to assess the changes in sympathovagal balance during graded orthostatic tilt (1994) Circulation, 90 (4), pp. 1826-1831Shoemaker, J.K., Hogeman, C.S., Khan, M., Kimmerly, D.S., Sinoway, L.I., Gender affects sympathetic and hemodynamic response to postural stress (2001) Am J Physiol Heart Circ Physiol, 281 (5), pp. H2028-H2035Bigger Jr, J.T., Fleiss, J.L., Steinman, R.C., Rolnitzky, L.M., Kleiger, R.E., Rottman, J.N., Correlations among time and frequency domain measures of heart period variability two weeks after acute myocardial infarction (1992) Am J Cardiol, 69 (9), pp. 891-898Almeida, M.B.E., Araújo, C.G.S., Effects of aerobic training on heart rate (2003) Rev Bras Med Esporte, 9 (2), pp. 113-120Yataco, A.R., Fleisher, L.A., Katzel, L.I., Heart rate variability and cardiovascular fitness in senior athletes (1997) Am J Cardiol, 80 (10), pp. 1389-1391Rennie, K.L., Hemingway, H., Kumari, M., Brunner, E., Malik, M., Marmot, M., Effects of moderate and vigorous physical activity on heart rate variability in a British study of civil servants (2003) Am J Epidemiol, 158 (2), pp. 135-14

    Comparison of cardiorespiratory responses between constant and incremental load exercises below, above and at the ventilatory anaerobic threshold

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    OBJECTIVE: To apply different analytical methodologies to data from continuous ramp tests (CRT) and discontinuous step tests (DST), and compare responses from cardiorespiratory parameters. METHOD: Eight men performed spirometric tests on an electrically braked cycle ergometer: CRT increasing from 20 to 25 W.min-1 and DST in 15-min steps, each based on the ventilatory anaerobic threshold (VAT) for CRT. Step 1 was 70% VAT; step 2, 100% VAT; and step 3, 130% VAT. VAT was determined as loss of parallelism between O2 uptake (VO2) and CO2 output (VCO2). Heart rate (HR, bpm), VCO2, VO2 (ml.min-1), VO2 (ml.kg.min-1) and ventilation (VE L.min-1) values for CRT were obtained as moving averages of eight breath-to-breath respiratory cycles, using linear regression. For DST, means were applied from the third to fifteenth minute of the steps. Statistical comparisons utilized the Kolmogorov-Smirnov test, ANOVA, post-hoc Tukey-Kramer test and linear regression, with significance limit of p0.05), but VO2 was different between VAT and all steps (p0,05), porém VO2 relativo foi diferente (p<0,05) entre LAV e todos os degraus; a FC mostrou diferença (p<0,05) entre LAV e degrau 3, e na análise entre os três degraus houve diferença (p<0,05). CONCLUSÃO: Os resultados indicam que a regressão linear foi eficaz para estimar as variáveis cardiorrespiratórias. Em relação aos protocolos, verificou-se que para a obtenção no TDD de valores cardiorrespiratórios similares ao LAV do TCR foi necessário diminuir a potência em 30%.16316

    Autonomic modulation of heart rate of young and postmenopausal women undergoing estrogen therapy

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    The aim of the present study was to determine whether estrogen therapy (ET) reduces alterations of the autonomic control of heart rate (HR) due to hypoestrogenism and aging. Thirteen young (24 ± 2.6 years), 10 postmenopausal (53 ± 4.6 years) undergoing ET (PM-ET), and 14 postmenopausal (56 ± 2.6 years) women not undergoing ET (PM) were studied. ET consisted of 0.625 mg/day conjugated equine estrogen. HR was recorded continuously for 8 min at rest in the supine and sitting positions. HR variability (HRV) was analyzed by time (SDNN and rMSSD indices) and frequency domain methods. Power spectral components are reported as normalized units (nu) at low (LF) and high (HF) frequencies, and as LF/HF ratio. Intergroup comparisons: SDNN index was higher in young (median: supine, 47 ms; sitting, 42 ms) than in PM-ET (33; 29 ms) and PM (31; 29 ms) women (P < 0.05). PM showed lower HFnu, higher LFnu and higher LF/HF ratio (supine: 44, 56, 1.29; sitting: 38, 62, 1.60) than the young group in the supine position (61, 39, 0.63) and the PM-ET group in the sitting position (57, 43, 0.75; P < 0.05). Intragroup comparisons: HR was lower in the supine than in the sitting position for all groups (P < 0.05). The HRV decrease from the supine to the sitting position was significant only in the young group. These results suggest that HRV decreases during aging. ET seems to attenuate this process, promoting a reduction in sympathetic activity on the heart and contributing to the cardioprotective effect of estrogen hormones.49149

    Analysis of spectral indexes for heart rate variability in middle-aged men and postmenopausal women

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    OBJECTIVE: To analyze and compare heart rate variability (HRV) in middle-aged men and women under resting conditions. METHOD: Ten men (54 &plusmn; 3.2 years) and fourteen postmenopausal women (56 &plusmn; 2.6 years) who were not using hormonal therapy were studied. Heart rates (HR) and R-R intervals (iR-R) on a beat-to-beat basis were obtained from electrocardiograms over an eight-minute period under resting conditions, in the supine and sitting positions. The HRV was analyzed in the frequency domain by means of fast Fourier transforms and the low (LF) and high (HF) frequency bands were obtained and presented as normalized units (LFnu and HFnu) and the LF/HF ratio. Wilcoxon and Mann-Whitney non-parametric statistical tests were used, with the significance level set at 5%. RESULTS: Comparing between the groups, the women presented significantly higher HFnu and lower LFnu and LF/HF ratios than did the men (p0.05) were found in the HRV indexes between the supine and sitting positions for either study group. CONCLUSION: Our results show greater vagal modulation and lower sympathetic activity in autonomic heart rate control among women than among men of similar age. This suggests that the gender-related autonomic differences are not solely dependent on estrogen levels, since the women studied were already postmenopausal. Other factors may be contributing towards these differences.OBJETIVO: Analisar e comparar a variabilidade da freqüência cardíaca (VFC), em repouso, de homens e mulheres de meia-idade. MÉTODOS: Foram estudados 10 homens (54 &plusmn; 3,2 anos) e 14 mulheres na pós-menopausa (56 &plusmn; 2,6 anos) que não faziam uso de terapia hormonal. A freqüência cardíaca (FC) e os intervalos R-R foram obtidos a partir do eletrocardiograma, batimento a batimento, durante 8 minutos em repouso, nas posições supina e sentada. A VFC foi analisada no domínio da freqüência, usando a transformada rápida de Fourier, por meio da qual foram obtidas as bandas de baixa (BF) e alta freqüência (AF), as quais foram expressas em unidades normalizadas (AFun) e (BFun) e na razão BF/AF. Foram utilizados os testes estatísticos não-paramétricos de Mann-Whitney e de Wilcoxon, com nível de significância de alfa= 5%. RESULTADOS: Na comparação intergrupo, as mulheres apresentaram maiores valores da banda AFun e menores valores da banda BFun e da razão BF/AF em relação aos homens, diferenças essas significativas (p<0,05). Na comparação intragrupo, não foram observadas diferenças significativas nos índices de VFC entre as posições supina e sentada para os 2 grupos estudados. CONCLUSÃO: Nossos resultados mostram uma maior modulação vagal e menor simpática no controle autonômico da FC para as mulheres em comparação aos homens de mesma idade, o que sugere que as diferenças autonômicas relacionadas ao gênero não se devem unicamente aos níveis hormonais de estrogênio, uma vez que as mulheres estudadas já se encontravam na fase pós-menopausa. Outros fatores podem estar contribuindo para essas diferenças.401406Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
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