Exercise training improves arterial baroreflex control in heart failure (HF) rabbits. However, the mechanisms involved in the amelioration of baroreflex control are unknown. We tested the hypothesis that exercise training would increase the afferent aortic depressor nerve activity (AODN) sensitivity in ischemic-induced HF rats. Twenty ischemic-induced HF rats were divided into trained (n = 11) and untrained (n = 9) groups. Nine normal control rats were also studied. Power spectral analysis of pulse interval, systolic blood pressure, renal sympathetic nerve activity (RSNA), and AODN were analyzed by means of autoregressive parametric spectral and cross-spectral algorithms. Spontaneous baroreflex sensitivity of heart rate (HR) and RSNA were analyzed during spontaneous variation of systolic blood pressure. Left ventricular end-diastolic pressure was higher in HF rats compared with that in the normal control group (P = 0.0001). Trained HF rats had a peak oxygen uptake higher than untrained rats and similar to normal controls (P = 0.01). Trained HF rats had lower low-frequency [1.8 +/- 0.2 vs. 14.6 +/- 3 normalized units (nu), P = 0.0003] and higher high-frequency (97.9 +/- 0.2 vs. 85.0 +/- 3 nu, P = 0.0005) components of pulse interval than untrained rats. Trained HF rats had higher spontaneous baroreceptor sensitivity of HR (1.19 +/- 0.2 vs. 0.51 +/- 0.1 ms/mmHg, P = 0.003) and RSNA [2.69 +/- 0.4 vs. 1.29 +/- 0.3 arbitrary units (au)/mmHg, P = 0.04] than untrained rats. In HF rats, exercise training increased spontaneous AODN sensitivity toward normal levels (trained HF rats, 1,791 +/- 215; untrained HF rats, 1,150 +/- 158; and normal control rats, 2,064 +/- 327 au/mmHg, P = 0.05). In conclusion, exercise training improves AODN sensitivity in HF rats.

No abstract

A variabilidade da frequência cardíaca (VFC) é reconhecida como importante marcador da integridade do sistema autonômico cardíaco. O processo de envelhecimento promove uma série de alterações na estrutura e função cardiovascular. O objetivo do estudo foi comparar a modulação autonômica cardíaca em mulheres fisicamente ativas de meia-idade e idosas através da análise simbólica da VFC. A amostra foi composta por mulheres fisicamente ativas de meia-idade (entre 40 e 59 anos, n=18) e idosas (≥ de 60 anos, n=12) que tiveram o eletrocardiograma (DII) e a respiração (cinta pneumográfica) registrados durante 5 minutos em posição supina. A VFC foi avaliada pela análise simbólica dos intervalos R-R, que distribuiu estes intervalos em 6 níveis (0 a 5) e agrupou-os em tríades de poder simbólico que foram classificadas em 4 famílias segundo as variações de símbolos presentes na tríade: 0V% (sem variação -associada à modulação simpática), 1V% (uma variação -sem predominâncias), 2V% (duas variações -associada à modulação parassimpática). Na análise estatística utilizou-se o teste de Mann-Whitney com p<0,05. Os grupos não apresentaram diferença significante na média dos intervalos R-R (p=0,219), variância total (p=0,421), entropia de Shannon (p=0,138) e para o padrão 1V% (p=0,138). O padrão 0V% (p=0,010) foi mais acentuado no grupo de idosas e 2V% (p=0,009) foi significantemente superior no grupo de meia-idade. A análise simbólica da VFC indicou que mulheres idosas apresentaram maior modulação simpática e menor modulação parassimpática comparadas às mulheres de meia idade.

No study has shown the effects of acute resistance exercise on vasodilatory capacity of patients with peripheral artery disease. The aim of this study was to analyse the effects of a single session of resistance exercise on blood flow, reactive hyperemia, plasma nitrite, and plasma malondialdehyde in patients with peripheral artery disease. Fourteen peripheral artery disease patients underwent, in a random order, 2 experimental sessions: control (rest for 30 min) and resistance exercise (8 exercises, 2 sets of 10 repetitions at an intensity of 5-7 in the OMNI Resistance Exercise Scale). Blood flow, reactive hyperemia, plasma nitrite, and malondialdehyde were measured before and 40 min after the interventions in both sessions. Data were compared between sessions by analysis of covariance, using pre-intervention values as covariates. The increases in blood flow, reactive hyperemia, and log plasma nitrite were greater (p ≤ 0.05) after resistance exercise than the control session (3.2 ± 0.1 vs. 2.7 ± 0.1 mL · 100 mL(-1) tissue · min(-1), 8.0 ± 0.1 vs. 5.7 ± 0.1 AU, and 1.36 ± 0.01 vs. 1.26 ± 0.01 μmol ∙ L(-1), respectively). On the other hand, malondialdehyde was similar between sessions (p > 0.05). In peripheral arterial disease patients, a single session of resistance exercise increases blood flow and reactive hyperemia, which seems to be mediated, in part, by increases in nitric oxide release.

The aim of this study was to compare the effects of a single session of walking and combined exercise on oxidative stress and vascular function in peripheral arterial disease patients. Thirteen patients with peripheral arterial disease underwent two experimental sessions in random order: walking (ten sets of 2-min walking at the speed corresponding to the onset of claudication pain with 2-min interval between sets) and combined exercise (1 × 10 reps in eight resistance exercises plus five-two-minute sets of walking). Before and after the exercise, vascular function (blood flow, leg vascular resistance and blood-flow postreactive hyperaemia) and oxidative stress (malondialdehyde and plasma nitrite levels) were obtained. Blood flow increased similarly after both sessions, whilst leg vascular resistance decreased similarly after both sessions. Plasma nitrite increased only after the combined exercise. Malondialdehyde decreased after both sessions, and the decrease was greater after combined exercise. As a conclusion, a single session of combined exercise improves blood flow and leg vascular resistance similarly to walking session; however, combined exercise promoted better effects on oxidative stress.