Changes in serum concentrations of taurine and other amino acids in clinical antihypertensive exercise therapy

Effects of Aerobic Training Progression on Blood Pressure in Individuals With Hypertension: A Systematic Review With Meta-Analysis and Meta-Regression

INTRODUCTION

Aerobic training of moderate intensity is the primary modality recommended in the management of hypertension. The manipulation of training variables can be an important strategy for the continuity of health benefits; however, little is known about the effects of the progression of aerobic training variables in the adaptations of blood pressure in hypertensive adults.

OBJECTIVE

To analyze, through a systematic review with meta-analysis, the effects of aerobic training with and without progression on systolic blood pressure (SBP) and diastolic blood pressure (DBP) in hypertensive adults.

METHOD

The search for the studies was carried out in the PubMed, Cochrane Central, SPORTDiscus and LILACS databases. Clinical trials that analyzed the effect of aerobic training, lasting at least six weeks, on blood pressure in hypertensive individuals comparing with a control group without intervention were selected. The selection of studies and data extraction were carried out independently by two pairs of researchers. The results are presented as mean difference and 95% confidence interval. Statistical significance was considered with p < 0.05.

RESULTS

Of the 13,028 studies found, 24 were selected and included in this review, 12 with progression of training variables and 12 without progression, with a total of 1,207 participants analyzed. There was a reduction in SBP after aerobic training with progression (-10.67 mmHg; 95% CI -15.421, -5.926; p < 0.001) and without progression (-10.17 mmHg; CI -12.213, -8.120; p < 0.001). DBP also decreased after aerobic training with progression (-5.49 mmHg; 95% CI -8.663, -2.310; p < 0.001) and without progression (-6.51 mmHg; 95% CI -9.147, -3.868; p < 0.001). According to the results of the meta-regression analyses, only age showed an association with the reduction of SBP (β: -0.323; CI -0.339, -0.307; p < 0.001).

CONCLUSION

Aerobic training promotes a reduction in the SBP and DBP levels of adults with hypertension, regardless of whether or not the training variables progression.

Taurine and Its Derivatives: Analysis of the Inhibitory Effect on Platelet Function and Their Antithrombotic Potential

Taurine is a semi-essential, the most abundant free amino acid in the human body, with a six times higher concentration in platelets than any other amino acid. It is highly beneficial for the organism, has many therapeutic actions, and is currently approved for heart failure treatment in Japan. Taurine has been repeatedly reported to elicit an inhibitory action on platelet activation and aggregation, sustained by in vivo, ex vivo, and in vitro animal and human studies. Taurine showed effectiveness in several pathologies involving thrombotic diathesis, such as diabetes, traumatic brain injury, acute ischemic stroke, and others. As human prospective studies on thrombosis outcome are very difficult to carry out, there is an obvious need to validate existing findings, and bring new compelling data about the mechanisms underlying taurine and derivatives antiplatelet action and their antithrombotic potential. Chloramine derivatives of taurine proved a higher stability and pronounced selectivity for platelet receptors, raising the assumption that they could represent future potential antithrombotic agents. Considering that taurine and its analogues display permissible side effects, along with the need of finding new, alternative antithrombotic drugs with minimal side effects and long-term action, the potential clinical relevance of this fascinating nutrient and its derivatives requires further consideration.

Effects of Exercise on the Resting Heart Rate: A Systematic Review and Meta-Analysis of Interventional Studies

Resting heart rate (RHR) is positively related with mortality. Regular exercise causes a reduction in RHR. The aim of the systematic review was to assess whether regular exercise or sports have an impact on the RHR in healthy subjects by taking different types of sports into account. A systematic literature research was conducted in six databases for the identification of controlled trials dealing with the effects of exercise or sports on the RHR in healthy subjects was performed. The studies were summarized by meta-analyses. The literature search analyzed 191 studies presenting 215 samples fitting the eligibility criteria. 121 trials examined the effects of endurance training, 43 strength training, 15 combined endurance and strength training, 5 additional school sport programs. 21 yoga, 5 tai chi, 3 qigong, and 2 unspecified types of sports. All types of sports decreased the RHR. However, only endurance training and yoga significantly decreased the RHR in both sexes. The exercise-induced decreases of RHR were positively related with the pre-interventional RHR and negatively with the average age of the participants. From this, we can conclude that exercise-especially endurance training and yoga-decreases RHR. This effect may contribute to a reduction in all-cause mortality due to regular exercise or sports.

Aerobic exercise and resting blood pressure: a meta-analytic review of randomized, controlled trials

In this study the authors used the meta-analytic approach to examine the effects of aerobic exercise on resting systolic and diastolic blood pressure in adults. Forty-seven clinical trials representing a total of 72 effect sizes in 2543 subjects (1653 exercise, 890 control) met the criteria for inclusion. Statistically significant exercise-minus-control decreases were found for changes in resting systolic and diastolic blood pressure in both hypertensive (systolic, -6 mm Hg, 95% CI, -8 to -3; diastolic, -5 mm Hg, 95% CI, -7 to -3) and normotensive (systolic, -2 mm Hg, 95% CI, -3 to -1; diastolic, -1 mm Hg, 95% CI, -2 to -1) groups. The differences between groups were statistically significant (systolic, p=0.008; diastolic, p=0.000). Relative decreases were approximately 4% (systolic) and 5% (diastolic) in hypertensives, and 2% (systolic) and 1% (diastolic) in normotensives. It was concluded that aerobic exercise reduces resting systolic and diastolic blood pressure in adults. (c) 2001 by CHF, Inc.

Exercise, a measure to lower blood pressure and reduce other risks

By 1990, exercise had been proven to lower blood pressure, and subsequently the intensity of exercise recommended was lowered from moderate to mild (lactic threshold or 50% maximum oxygen uptake). Exercise is now recommended as a useful measure to lower blood pressure in many guidelines for the management of hypertension. The antihypertensive mechanism is multifactorial involving sympathicolytic as well as diuretic actions through activation of relevant metabolic pathways; that is, decrease in endogenous ouabain-like substance, increase in s-taurine and prostaglandin E and urinary dopamine and kallikrein excretion, etc. Other metabolic changes seem to operate simultaneously, and other risk factors, such as sugar and lipid metabolism and insulin resistance are improved. Prospective epidemiologic study has suggested that a physically active lifestyle will prevent cardiovascular complications.

Hypertension and exercise

A sedentary lifestyle may be a risk for hypertension, according to the results of both cross sectional and longitudinal studies. However, exercise may reverse the adverse effects of lack of activity. Many controlled studies have shown that exercise lowers systolic/diastolic blood pressure by at least 10/5 mmHg. Exercise not only improves blood pressure, but also attenuates other risk factors for cardiovascular complications. Dynamic isotonic exercise (e.g., weight lifting). Milder (e.g., brisk walking for 30-60 minutes/day) rather than moderate to severe exercise (e.g., running) is also recommended because of similar effectiveness and better compliance. The underlying mechanism of action of exercise on blood pressure seems to be multifactorial involving a decrease in pressor factors such as plasma norepinephrine, the serum Na/K ratio, endogenous ouabain-like substance and erythrocyte mean corpuscular volume, as well as an increase in depressor factors such as plasma prostaglandin E, serum taurine and urinary dopamine excretion.

Hypertension and exercise. Where do we stand?

Several risk factors have been identified in patients with essential hypertension. The question is whether regular exercise programs can either prevent or alleviate elevated blood pressure. Published studies generally indicate that aerobic exercise of large-muscle groups can be used as an interventional regimen for hypertension. For mild hypertension, moderate-intensity walking is recommended at least three times a week. Improvement may not be evident in less than 6 months. When exercise alone is not effective or when hypertension is more severe, exercise can still be used as an adjunct to pharmacologic therapy.

Non-pharmacologic measures for lowering blood pressure

Nondrug measures have proven effective, to some extent, in lowering blood pressure, especially in mild hypertensives, in many well-controlled studies. The proven measures are reduction of a) salt (less than 5 g/day), b) alcohol (less than 30 ml/day) intake, and c) obesity, and d) regular physical exercise (30-60 minutes/day) and e) mental relaxation. The reported effectiveness of each of these measures ranges from one third to two thirds in mild hypertensives. Should all these nondrug measures, together with cessation of smoking, be applied in all mild hypertensives, it might help prevent their progression to moderate or even severe hypertension with complications, such as coronary heart disease in particular, thereby solving most of the problems that antihypertensive drugs have left behind.