Efeitos do exercício prévio sobre o desempenho intermitente em jogadoras amadoras de futsal / Ffects of previous exercise on intermittent performance in amateur futsal players

O objetivo do presente estudo foi avaliar os efeitos do exercício prévio específico sobre o desempenho em teste intermitente de alta intensidade em jogadoras de futsal e variáveis associadas. Para isso 13 jogadoras amadoras de futsal (24,1 anos; 63,6 kg; 1,61 m; IMC = 24,3 kg/m2 ; % de gordura = 27,9), de maneira cruzada, passaram por duas sessões experimentais separadas por sete dias. Em uma das sessões era realizado um exercício prévio (EP): três primeiros níveis do Yo Yo intermittent recovery test level 1 (YYIR1) repetidos por três vezes. Na sessão controle (CON), as jogadoras permaneciam em repouso (5 min) e após, em ambas as sessões, era realizado o YYIR1 até a exaustão. Antes do início da sessão eram reportadas escalas de recuperação e dor muscular de início tardio, a frequência cardíaca (FC) foi monitorada por toda sessão e, ao término, a percepção de esforço (PSE) era registrada. As percepções de recuperação (p = 0,23) e de dor (p = 0,36) não diferiram entre as sessões EP vs. CON. A FC média durante o exercício prévio foi de 111,3 ± 7,7 bpm. A distância percorrida no YYIR1 não diferiu (p = 0,25) também entre EP (372,3 ± 103,8 m) vs. CON (341,5 ± 84,2 m), bem como a monitoração da FC (mínima, média e máxima). Entretanto, a PSE foi menor (p = 0,0008) na sessão EP (8,5 ± 0,7 UA) do que em CON (9,3 ± 0,6 UA). Assim, concluímos que o exercício prévio não influencia o desempenho intermitente de alta intensidade (YYIR1), nem as variáveis de FC. Porém, o exercício prévio gera menores níveis de percepção de esforço (intensidade interna) em comparação ao repouso antes do YYIR1. (AU)

The aim of the present study was to evaluate the effects of specific prior exercise on performance in intermittent high intensity testing in futsal players and associated variables. For this, 13 amateur futsal players (24.1 years old; 63.6 kg; 1.61 m; BMI = 24.3 kg / m2; fat% = 27.9), in a crossed way, went through two experimental sessions separated by seven days. In one of the sessions, a previous exercise (PE) was performed: the first three levels of the Yo Yo intermittent recovery test level 1 (YYIR1) repeated three times. In the control session (CON), the players remained at rest (5 min) and afterwards, in both sessions, YYIR1 was performed until exhaustion. Before the start of the session, recovery scales and late-onset muscle pain were reported, the heart rate (HR) was monitored throughout the session and, at the end, the perceived exertion (RPE) was recorded. The perceptions of recovery (p = 0.23) and pain (p = 0.36) did not differ between the PE vs CON. The average HR during the previous exercise was 111.3 ± 7.7 bpm. The distance covered in YYIR1 did not differ (p = 0.25) also between PE (372.3 ± 103.8 m) vs. CON (341.5 ± 84.2 m), as well as HR monitoring (minimum, average and maximum). However, the RPE was lower (p = 0.0008) in the PE session (8.5 ± 0.7 AU) than in CON (9.3 ± 0.6 AU). Thus, we conclude that the previous exercise does not influence the intermittent high intensity performance (YYIR1), nor the HR variables. However, previous exercise generates lower levels of perceived exertion (internal intensity) compared to resting before YYIR1. (AU)

Low levels of dehydroepiandrosterone sulfate are associated with the risk of developing cardiac autonomic dysfunction in elderly subjects

ABSTRACT Objective: To assess the relationships between serum dehydroepiandrosterone sulfate (DHEA-S) levels and heart rate variability (HRV) among different age groups. Subjects and methods: Forty-five healthy men were divided into 3 groups: young age (YA; 20-39 yrs; n = 15), middle age (MA; 40-59 yrs; n = 15) and old age (OA; ≥ 60 yrs; n = 15). Hemodynamic parameters, linear analyses of HRV and concentrations of cortisol and DHEA-S were measured at rest. Results: The OA group presented a higher resting heart rate (84.3 ± 4.6 bpm) than the YA group (72.0 ± 4.4 bpm; p < 0.05). The YA group showed an attenuated variance of HRV (2235.1 ± 417.9 ms2) compared to the MA (1014.3 ± 265.2 ms2; p < 0.05) and OA (896.3 ± 274.1 ms2; p < 0.05) groups, respectively. The parasympathetic modulation of HRV was lower in both the MA (244.2 ± 58.0 ms2) and OA (172.8 ± 37.9 ms2) groups in comparison with the YA group (996.0 ± 255.4 ms2; p < 0.05), while serum DHEA-S levels were significantly lower in both the MA (91.2 ± 19.6 mg/dL) and OA (54.2 ± 17.7 mg/dL) groups compared to the YA group (240.0 ± 50.8 mg/dL; p < 0.05). A positive correlation between lower serum concentrations of DHEA-S and attenuated variance of HRV (r = 0.47, p = 0.031), as well as lower serum concentrations of DHEA-S and decreased parasympathetic modulation of HRV (r = 0.54, p = 0.010), were found. Conclusion: The present study demonstrated that the decline of plasma DHEA-S is associated with reduced cardiac autonomic modulation during the aging process.

Exercise Training Attenuates Sympathetic Activity and Improves Morphometry of Splenic Arterioles in Spontaneously Hipertensive Rats / Treinamento Físico Atenua a Atividade Simpática e Melhora a Morfometria das Arteríolas Esplênicas em Ratos Espontaneamente Hipertensos

Abstract Background: Alterations in the structure of resistance vessels contribute to elevated systemic vascular resistance in hypertension and are linked to sympathetic hyperactivity and related lesions in target organs. Objective: To assess the effects of exercise training on hemodynamic and autonomic parameters, as well as splenic arteriolar damages in male Wistar Kyoto (WKY) and Spontaneously Hypertensive Rats (SHR). Methods: Normotensive sedentary (WKYS) and trained (WKYT) rats, and hypertensive sedentary (SHRS) and trained (SHRT) rats were included in this study. After 9 weeks of experimental protocol (swimming training or sedentary control), arterial pressure (AP) and heart rate (HR) were recorded in freely moving rats. We assessed the autonomic control of the heart by sympathetic and vagal autonomic blockade. Morphometric analyses of arterioles were performed in spleen tissues. The statistical significance level was set at p < 0.05. Results: Resting bradycardia was observed in both trained groups (WKYT: 328.0 ± 7.3 bpm; SHRT: 337.0 ± 5.2 bpm) compared with their respective sedentary groups (WKYS: 353.2 ± 8.5 bpm; SHRS: 412.1 ± 10.4 bpm; p < 0.001). Exercise training attenuated mean AP only in SHRT (125.9 ± 6.2 mmHg) vs. SHRS (182.5 ± 4.2 mmHg, p < 0.001). The WKYT showed a higher vagal effect (∆HR: 79.0 ± 2.3 bpm) compared with WKYS (∆HR: 67.4 ± 1.7 bpm; p < 0.05). Chronic exercise decreased sympathetic effects on SHRT (∆HR: -62.8 ± 2.8 bpm) in comparison with SHRS (∆HR: -99.8 ± 9.2 bpm; p = 0.005). The wall thickness of splenic arterioles in SHR was reduced by training (332.1 ± 16.0 µm2 in SHRT vs. 502.7 ± 36.3 µm2 in SHRS; p < 0.05). Conclusions: Exercise training attenuates sympathetic activity and AP in SHR, which may be contributing to the morphological improvement of the splenic arterioles.

Resumo Fundamento: Alterações na estrutura dos vasos de resistência contribuem para elevar a resistência vascular sistêmica na hipertensão, estando ligadas à hiperatividade simpática e lesões em órgãos-alvo. Objetivo: Avaliar os efeitos do treinamento físico nos parâmetros hemodinâmicos e autônomos, assim como as lesões arteriolares esplênica em ratos machos Wistar Kyoto (WKY) e espontaneamente hipertensos (SHR). Métodos: Ratos normotensos sedentários (WKYS) e treinados (WKYT), e ratos hipertensos sedentários (SHRS) e treinados (SHRT) foram incluídos neste estudo. Após nove semanas de aplicação do protocolo experimental (treinamento de natação ou controle sedentário), registraram-se a pressão arterial (PA) e a frequência cardíaca (FC) dos ratos em movimento livre. Avaliamos o controle autônomo do coração através de bloqueio autônomo simpático e vagal. Análises morfométricas das arteríolas esplênicas foram realizadas. Adotou-se o nível de significado estatístico de p < 0,05. Resultados: Observou-se bradicardia de repouso nos dois grupos treinados (WKYT: 328,0 ± 7,3 bpm; SHRT: 337,0 ± 5,2 bpm) em comparação aos seus respectivos grupos sedentários (WKYS: 353,2 ± 8,5 bpm; SHRS: 412,1 ± 10,4 bpm; p < 0,001). O treinamento físico atenuou a PA média apenas no grupo SHRT (125,9 ± 6,2 mmHg vs. 182,5 ± 4,2 mmHg no SHRS; p < 0,001). O grupo WKYT mostrou maior efeito vagal (∆FC: 79,0 ± 2,3 bpm) em comparação ao grupo WKYS (∆FC: 67,4 ± 1,7 bpm; p < 0,05). Exercício crônico diminuiu os efeitos simpáticos em SHRT (∆FC: -62.8 ± 2.8 bpm) em comparação a SHRS (∆FC: -99,8 ± 9,2 bpm; p = 0,005). A espessura da parede das arteríolas esplênicas nos SHR foi reduzida pelo treinamento (332,1 ± 16,0 µm2 nos SHRT vs. 502,7 ± 36,3 µm2 nos SHRS; p < 0,05). Conclusões: O treinamento físico atenua a atividade simpática e a PA em SHR, o que pode contribuir para melhorar a morfologia das arteríolas esplênicas.

Exercise training reverse autonomic dysfunction and hypertension in rats fed with high-fat diet

AIMS: We evaluated whether exercise training ameliorates cardiovascular autonomic dysfunction in obesity-induced by high-fat diet (HFD) in rats. METHODS Wistar male rats were assigned in normal diet, sedentary (ND-S) and trained (ND-T) and HFD, sedentary (HFD-S) and trained (HFD-T). Blood pressure (BP), heart rate (HR), HR variability (HRV), BP variability (BPV), cardiac baroreflex and cardiac autonomic tonus were assessed. HFD-S showed higher bodyweight increase (19.4%) compared to all other groups (HFD-T: 13.2%, ND-S: 14% and ND-T: 12.4%). Relative epididymal, retroperitoneal and visceral fat was also greater in HFD-S compared to all other groups. Resting bradycardia in ND-T (339.5±10.6 bpm) and HFD-T (341.0 ± 9.4 bpm) was more pronounced than ND-S (438.4 ± 6.3 bpm; p<0.05) and HFD-S (448.5 ± 18.7 bpm; p<0.05). The HFD-T group showed lower systolic (125.3 ( 1.9 mmHg), diastolic (88.5 ( 2.0 mmHg) and mean BP (100.3 ± 2.5 mmHg) in comparison with HFD-S (153.8 ( 3.7; 103.5 ( 2.6 and 120.5 ± 3.7 mmHg; p<0.05, respectively). Lower variance of HRV and higher variance of diastolic BPV was observed in HFD-S compared to other groups while sympathetic modulation of HRV and BPV was higher in HFD-S, as well as the LF/HF ratio. HFD-T showed a decrease in sympathetic tonus compared to HFD-S. ND-T and HFD-T showed higher cardiac vagal tonus than respective sedentary groups. Analysis showed an association between visceral fat, sympathetic activity and BP. CONCLUSIONS: HFD induces hypertension and is associated with autonomic imbalance in rats, while exercise training may reverse these harmful changes.(AU)