Exercise, cardiovascular disease, and chronic heart failure

Beneficial effects of swimming and pomegranate juice in rats with hypertension: A possible role of serum adropin

Hypertension, characterized by persistent and uncontrolled high blood pressure, is one of the most common significant causes of mortality worldwide. Lifestyle modifications such as exercise and antioxidant intake have showed beneficial effects on hypertensive conditions. Adropin and endothelin-1 (ET-1) have important vasoregulatory functions in the endothelium. However, the underlying mechanisms linking exercise- and/or antioxidant intake-mediated improvement of hypertension are not fully understood. In this study, it was hypothesized that swimming exercise and pomegranate juice (PJ) (as an antioxidant) administration might have protective effects on hypertension development and possible involvements of serum adropin and ET-1. To test the hypothesis, the rats with hypertension, induced by Nω-nitro-L-arginine methyl ester hydrochloride, were subjected to swimming exercise and received PJ for 8 weeks. Weekly systolic and diastolic pressures, serum concentrations of adropin and ET-1, and oxidant/antioxidant parameters in various tissues were measured. The obtained data show that swimming exercise leads to complete protection against hypertension within the 8-week duration, whereas the PJ administration causes an ameliorative effect. In addition, the combination of swimming exercise and PJ administration do not have additive effects in protection against hypertension. Notably, the 8-week swimming exercise restores the diminished serum adropin concentration in rats with hypertension to the control level. Serum adropin significantly correlated with systolic and diastolic pressures, depending on swimming exercise, but not PJ administration. Serum ET-1 concentration inconsistently fluctuates in response to Nω-nitro-L-arginine methyl ester hydrochloride, swimming exercise, and PJ intake. In addition, swimming exercise and/or PJ administration lead to a complete normalization in liver malondialdehyde concentrations of rats with hypertension, whereas these interventions cause slight or no improvements in superoxide dismutase, catalase, and glutathione in the heart, liver, and kidney. In conclusion, 8-week swimming exercise modulates hypertension, possibly by influencing adropin concentration and oxidative stress.

The effect of swimming training on adrenomedullin levels, oxidative stress variables, and gastrocnemius muscle contractile properties in hypertensive rats

Introduction/Aim: Regular exercise may have beneficial effects on high blood-pressure, as shown in different types of experimental hypertension models in rats. The present study aims to investigate the effects of 6-week swimming training on blood pressure, oxidative stress variables of selected tissues, serum adrenomedullin (ADM) levels, and in situ muscle contraction in rats with hypertension induced by Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME), an inhibitor of endothelial nitric oxide synthases (eNOs). Materials and Methods: Twenty-six male Sprague Dawley, 8 weeks of age, rats were randomly divided into four groups: (I) normotensive (C), (II) normotensive + exercise (E), (III) hypertensive (L), and (IV) hypertensive + exercise (LE). Hypertension was induced by the oral administration of L-NAME (60 mg/kg) for 6 weeks. Exercise was performed 5 times (1-h each) per week for 6 weeks. At the end of the experiment, blood and tissue samples (the gastrocnemius muscle, heart, kidney, and thoracic aorta) were collected following contractile properties of the gastrocnemius muscle in situ weredetermined. In the collected tissues, oxidative stress (e.g., lipid oxidation and antioxidant enzyme activity) and serum ADM levels were measured. 6-week L-NAME administration per se (Group L) led to a significant increase in systolic and diastolic blood pressure compared to other groups.  Results: Importantly, 6-week exercise caused a protective effect of high blood pressure in the rats received L-NAME (Group LE). The level of ADM was lower in the rats received L-NAME than that of the control group. L-NAME increased lipid peroxidation in the thoracic aorta and decreased superoxide dismutase in the heart, kidney and muscle, and decreased catalase and glutathione in the heart. However, the exercise intervention did not have protective effect on the L-NAME-mediated oxidative damage in the collected tissues.  Conclusion: In conclusion, 6-week exercise intervention rescued rats from high blood pressure, but did not have ameliorative effect on the decreased ADM levels.

Exercise-induced hypertension can increase the prevalence of coronary artery plaque among middle-aged male marathon runners

Marathon runners demonstrate a high incidence of coronary artery plaque; however, studies on runners with exercise-induced hypertension (EIH) are sparse. We aimed to investigate the prevalence of coronary artery plaque among marathon runners with EIH.Veteran male marathon runners (≥40 and <60 years) underwent an exercise stress test. They were divided into 2 groups: normal blood pressure group (NBPG, n = 22), with resting systolic blood pressure (SBP)/diastolic blood pressure <140/90 mm Hg and maximal exercise SBP <210 mm Hg, and EIH group (EIHG, n = 28), with resting blood pressure <140/90 mm Hg and maximal exercise SBP ≥210 mm Hg. Coronary artery plaque and stenosis were compared using multi-detector computed tomography.The proportion of subjects with a coronary artery calcium (CAC) score ≥10 or ≥100 units, 1 or ≥2 plaques, or plaques in ≥2 blood vessels was higher in the EIHG than in the normal blood pressure group (NBPG) (P<.05). The absolute CAC score was higher in the EIHG (42.6 ± 67.8) than in the NBPG (2.8 ± 6.0; P < .05). The CAC score distribution was higher in the EIHG (5-300 units) than in the NBPG (P < .05). The prevalence of coronary plaques and maximal luminal artery stenosis was higher in the EIHG than in the NBPG (P < .05). The EIHG showed 12 cases of stenosis, whereas the NBPG showed only 1 case (P < .05).In marathon runners, EIH was associated with increased prevalence of coronary artery plaques and could be a new risk factor for coronary artery plaque formation. Therefore, preventive measures and EIH monitoring using an exercise stress test, alongside multi-detector computed tomography, are recommended.

Cardiac rehabilitation and artificial heart devices

Recently, cardiac rehabilitation has gained popularity in Japan because beneficial effects on patients' prognosis have been reported. Another reason is that cardiac rehabilitation has been covered by health insurance since 1988 in Japan. Currently, cardiac rehabilitation is covered for the diseases of angina pectoris, acute myocardial infarction, chronic heart failure (CHF), peripheral arterial disease, and diseases of the aorta and after open-heart surgery. Left ventricular assist devices (LVADs) are sometimes used in patients with progressive CHF symptoms to provide circulatory support, because in most of these patients heart failure does not improve with application of medical therapy, intra-aortic balloon pumping, or a percutaneous cardiopulmonary system. Modern VAD control systems are compact, allowing patients to carry them around without difficulty. Since patient management at the outpatient clinic has become possible, patients are able to expand the scope of their activities. Early active rehabilitation in patients implanted with a LVAD improves their condition, favorably impacts the clinical course while they await heart transplantation, and also improves posttransplant recovery. Exercise therapy is one of the important components in comprehensive cardiac rehabilitation. Exercise therapy is important to improve the quality of life of patients with LVADs. Appropriate exercise therapy is effective for patients with various cardiac conditions who undergo diverse treatments and is practiced actively by many patients. In order to facilitate cardiac rehabilitation safely and effectively for patients with serious conditions, education for health care professionals is essential. In this review, we describe the concept of rehabilitation followed by cardiac rehabilitation for patients with heart failure, patients after open-heart surgery, and patients with implanted LVADs.

Rehabilitation of a Functionally Limited, Chronically Ill Older Adult: A Case Study

This case study presents MV, a 78-year-old woman who was being treated pharmacologically for several common chronic health problems and who presented with self-reported and observed limitations in her functional ability. After being screened for contraindications to exercise, MV participated in a 16-week rehabilitation program of regular exercise that included aerobic and resistance training. She maintained a high level of compliance with this rehabilitation training and showed improvements in her aerobic capacity, strength, ability to complete functional tasks, blood components, and lipid profile. She also reported decreased levels of pain and improved perceptions of functional ability. This case study indicates that older adults with chronic illness can benefit from participating in a program of regular exercise.

Cardiorespiratory fitness and functional capacity assessed by the 20-meter shuttle walking test in patients with coronary artery disease

OBJECTIVE

To validate the 20-meter shuttle walking test (20MST) in the assessment of maximal oxygen consumption (VO(2)max) and maximal speed in patients with coronary artery disease (CAD).

DESIGN

Single-sample validity study.

SETTING

Cardiac rehabilitation service in France.

PARTICIPANTS

Seventeen men with CAD.

INTERVENTIONS

Subjects underwent a symptom-limited treadmill test (SLTT) in a laboratory, with a speed starting at 2.5km/h and increasing by 0.5km/h every minute, and performed an adapted 20MST in a corridor, with a speed starting at 3km/h and increasing by 1km/h every minute until exhaustion.

MAIN OUTCOME MEASURES

VO(2) measured during the 20MST with the Cosmed K2 telemetric gas analyzer (K2 VO(2)), estimated VO(2) calculated by the Léger equation (Léger VO(2)) from the maximal speed obtained during the 20MST, and VO(2) measured during the SLTT (SLTT VO(2)). Maximal speeds attained on the treadmill and on the 20MST were also compared.

RESULTS

A significant (P<.0001) difference was observed between the Léger estimate of VO(2) and those of K2 VO(2) and SLTT VO(2) (mean +/- standard deviation, 12.28+/-5.90mL. min(-1).kg(-1) vs 23.04+/-7.17 and 22.56+/-6.29mL.min(-1).kg(-1)). No difference was found between the treadmill and the 20MST maximal speeds (6.73+/-0.91km/h, 6.78+/-1.23km/h, respectively). Measured with the Cosmed K2, a significant relationship existed between VO(2) and each speed level (r=.95, P<.0001; VO(2)=4.24x speed-7.37, standard estimation error=2.29mL.min(-1).kg(-1)).

CONCLUSION

Maximal VO(2) and maximal speed measured on the treadmill did not differ significantly from those obtained on the 20MST. The current 20MST equation (Léger equation) was not valid to estimate VO(2) in CAD patients. A modified prediction equation of VO(2) was given and would need a larger number of patients to be generalized.

Oxidative injury due to chronic nitric oxide synthase inhibition in rat: effect of regular exercise on the heart

Many individuals with cardiac diseases undergo periodic physical conditioning with or without medication. Therefore, this study investigated the interaction of physical training and chronic nitric oxide synthase (NOS) inhibitor (nitro-L-arginine methyl ester, L-NAME) treatment on blood pressure (BP), heart rate (HR) and cardiac oxidant/antioxidant systems in rats. Fisher 344 rats were divided into four groups and treated as follows: (1) sedentary control (SC), (2) exercise training (ET) for 8 weeks, (3) L-NAME (10 mg/kg, s.c. for 8 weeks) and (4) ET+L-NAME. BP and HR were monitored with tail-cuff method. The animals were sacrificed 24 h after last treatments and hearts were isolated and analyzed. Physical conditioning significantly increased respiratory exchange ratio (RER), cardiac nitric oxide (NO) levels, NOS activity and endothelial (eNOS) and inducible (iNOS) protein expression. Training significantly enhanced cardiac glutathione (GSH) levels, GSH/GSSG ratio and up-regulation of cardiac copper/zinc-superoxide dismutase (CuZn-SOD), manganese (Mn)-SOD, catalase (CAT), glutathione peroxidase (GSH-Px) activity and protein expression. Training also caused depletion of cardiac malondialdehyde (MDA) and protein carbonyls. Chronic L-NAME administration resulted in depletion of cardiac NO level, NOS activity, eNOS, nNOS and iNOS protein expression, GSH/GSSG ratio and down-regulation of cardiac CuZn-SOD, Mn-SOD, CAT, GSH-PX, glutathione-S-transferase (GST) activity and protein expression. Chronic L-NAME administration enhanced cardiac xanthine oxidase (XO) activity, MDA levels and protein carbonyls. These biochemical changes were accompanied by increases in BP and HR after L-NAME administration. Interaction of training and NOS inhibitor treatment resulted in normalization of BP, HR and up-regulation of cardiac antioxidant defense system. The data suggest that physical conditioning attenuated the oxidative injury caused by chronic NOS inhibition by up-regulating the cardiac antioxidant defense system and lowering the BP and HR in rats.