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| Author(s): |
Ricardo Saraceni Gomides
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Escola de Educação Física e Esportes (EEFE/BT) |
| Defense date: | 2009-03-27 |
| Examining board members: |
Cláudia Lúcia de Moraes Forjaz;
Patricia Chakur Brum;
Kátia de Angelis Lobo D\'Avila
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| Advisor: | Cláudia Lúcia de Moraes Forjaz |
| Abstract | |
Dynamic resistance exercise is recommended in association to aerobic exercise for hypertensive patients. Blood pressure increase during this kind of exercise is mainly due to an increase in peripheral vascular resistance, however, an increase in cardiac output might also be involved. This blood pressure increase seems to be exacerbated in non-medicated hypertensives. Nevertheless, most of the hypertensives are taking medications, and some of them are receiving -blockers, which decreases cardiac output by the inhibition of sympathetic-induced increase on heart rate and cardiac contractility. Thus, -blockers might decrease blood pressure rise during resistance exercise which, to our knowledge, has not been studied yet. Hence, the aim of this study was to verify the effects of the selective -blocker atenolol on blood pressure increase during dynamic resistance exercise of different intensities. Ten essential hypertensives with systolic/diastolic blood pressures under placebo condition maintained among 140 and 160/90 and 105 mmHg were recruited. These volunteers were studied after 6 weeks of placebo and atenolol treatment, and they were blinded for the medication used. In each phase, the volunteers executed, in a random order, 3 protocols of knee extension exercise until fatigue: a) 1 set at 100% of 1 repetition maximum (1RM); b) 3 sets at 40% of 1RM; c) 3 sets at 80% of 1RM. Before, during and after the exercises, intra-arterial radial blood pressure was measured. Data were compared by paired student t-test and by two-way ANOVA for repeated measures. Newman-Keuls post-hoc test was applied when necessary. P≤0.05 was considered as significant. Atenolol decreased the absolute value achieved by systolic blood pressure during the exercise performed at the 3 intensities (maximum values: 100% = 186±4 vs. 215±7, 80%= 224±7 vs. 247±9 e 40% = 223±7 vs. 252±16, mmHg, P≤0.05). Moreover, atenolol also reduced systolic blood pressure increase in the first set of exercise at the 3 intensities (100% = +38±5 vs. +54±9; 80% = +68±11 vs. +84±13 e 40% = +69±7 vs. +84±14, mmHg, P≤0.05). In regard to diastolic blood pressure, atenolol decreased its absolute values and its increase during exercise performed at 100% of 1RM (126±6 vs. 145±6 e +41±6 vs. +52±6, mmHg, P≤0.05), but it did not change diastolic blood pressure at the other exercise intensities. In Conclusion, atenolol therapy was effective in reducing both, systolic blood pressure absolute values and increase during resistance exercise of different intensities in hypertensive subjects; given them some cardiovascular protection. This result enhances the belief that cardiac output increase is important for blood pressure enhancement during this kind of exercise (AU) | |