Exercise tolerance and alcohol intake. Blood pressure relation

A prediction model of blood pressure for telemedicine

This paper presents a new study based on a machine learning technique, specifically an artificial neural network, for predicting systolic blood pressure through the correlation of variables (age, BMI, exercise level, alcohol consumption level, smoking status, stress level, and salt intake level). The study was carried out using a database containing a variety of variables/factors. Each database of raw data was split into two parts: one part for training the neural network and the remaining part for testing the performance of the network. Two neural network algorithms, back-propagation and radial basis function, were used to construct and validate the prediction system. According to the experiment, the accuracy of our predictions of systolic blood pressure values exceeded 90%. Our experimental results show that artificial neural networks are suitable for modeling and predicting systolic blood pressure. This new method of predicting systolic blood pressure helps to give an early warning to adults, who may not get regular blood pressure measurements that their blood pressure might be at an unhealthy level. Also, because an isolated measurement of blood pressure is not always very accurate due to daily fluctuations, our predictor can provide the predicted value as another figure for medical staff to refer to.

Effect of Voluntary Ethanol Consumption Combined with Testosterone Treatment on Cardiovascular Function in Rats: Influence of Exercise Training

This study evaluated the effects of voluntary ethanol consumption combined with testosterone treatment on cardiovascular function in rats. Moreover, we investigated the influence of exercise training on these effects. To this end, male rats were submitted to low-intensity training on a treadmill or kept sedentary while concurrently being treated with ethanol for 6 weeks. For voluntary ethanol intake, rats were given access to two bottles, one containing ethanol and other containing water, three 24-hour sessions per week. In the last two weeks (weeks 5 and 6), animals underwent testosterone treatment concurrently with exercise training and exposure to ethanol. Ethanol consumption was not affected by either testosterone treatment or exercise training. Also, drug treatments did not influence the treadmill performance improvement evoked by training. However, testosterone alone, but not in combination with ethanol, reduced resting heart rate. Moreover, combined treatment with testosterone and ethanol reduced the pressor response to the selective α₁-adrenoceptor agonist phenylephrine. Treatment with either testosterone or ethanol alone also affected baroreflex activity and enhanced depressor response to acetylcholine, but these effects were inhibited when drugs were coadministrated. Exercise training restored most cardiovascular effects evoked by drug treatments. Furthermore, both drugs administrated alone increased pressor response to phenylephrine in trained animals. Also, drug treatments inhibited the beneficial effects of training on baroreflex function. In conclusion, the present results suggest a potential interaction between toxic effects of testosterone and ethanol on cardiovascular function. Data also indicate that exercise training is an important factor influencing the effects of these substances.

Derivation of tolerable upper alcohol intake levels in Germany: a systematic review of risks and benefits of moderate alcohol consumption

BACKGROUND

The objective of this study is to weigh the risks of moderate alcohol consumption against its benefits and, as a result, to derive tolerable upper alcohol intake levels (TUALs) for the German adult population.

METHODS

Human studies assessing the effects of moderate alcohol consumption (< or = 40 g/day) on coronary heart disease, stroke, blood pressure, diseases of the liver, gallbladder, bile duct, and pancreas, cancer of the mouth/pharynx/larynx/oesophagus, stomach, colon/rectum, and breast, foetal alcohol syndrome/foetal alcohol effects, as well as all-cause mortality, published in the 10-15 years before 1999, have been systematically reviewed. The quality of studies has been evaluated using a self-constructed evaluation scheme. As a result of comparing the critical endpoints of alcohol intake related to morbidity and mortality, the TUALs have been derived.

RESULTS

The TUALs have been set at 10-12 g/day for healthy women and 20-24 g/day for healthy men of the adult population (18 years and older). Additional guidelines on alcohol use have been defined, taking into account further important aspects like alcohol consumption patterns and high-risk groups.

CONCLUSIONS

The TUALs are not intended to be recommended intake levels. However, if the TUALs and the additional guidelines are followed, a relation of alcohol consumption to an increased risk of alcohol-associated diseases is unlikely for the majority of the population.

Alcohol usage in sport and exercise

In this review we consider some of the acute and chronic effects of alcohol on human exercise and sport performance. The 1982 position stand of the American College of Sport Medicine on the use of alcohol in sport emphasized that there was little benefit for an athlete. Subsequent literature continues to demonstrate that there are adverse effects on performance. However, the literature is often confusing and disparate. We will attempt to explain the effects and speculate on the possible mechanisms. We divide the review into acute and chronic metabolic and physiological effects of alcohol on exercise performance, primarily in humans. We also review the epidemiological evidence of the associations between alcohol use and problem alcohol behaviors in various athletic groups. Finally, we review the limited data on the effectiveness of exercise therapy in the treatment of alcohol dependent patients. In spite of scientific evidence that alcohol use is, in general, detrimental (or of no benefit) to sport (exercise) performance, alcohol continues to be used by athletes both on a chronic basis and even immediately prior to sports participation. There is some encouraging but limited evidence that student-athlete alcohol use is decreasing and exercise can be effective as part of alcohol rehabilitation.

Associations between lifestyle and cardiovascular risk factors in 18-year-old Australians

PURPOSE

This study aimed to examine associations between cardiovascular risk factors and variables reflecting health-related behaviors in 18-year-old Australians.

METHODS

Anthropometry, blood pressure, nonfasting serum cholesterol, and physical fitness were measured in 301 male and 286 female Australian 18-year-olds. Usual physical activity, smoking, and drinking habits were assessed by questionnaire.

RESULTS

Systolic (SBP), with mean SBP higher by 14 mm Hg in males, related positively to weight for height for age and "unsafe" drinking (exceeding Australian national guidelines) and negatively to fitness and birth weight. Total cholesterol, which was positively associated with waist-hip ratio and negatively with fitness, was higher in females [mean 4.4 mmol/L, 95% confidence interval (CI) 4.3, 4.5] than in males (mean 4.1 mmol/L, 95% CI 4.0, 4.2). In 24% of males and 48% of females, usual levels of physical activity were low, consistent with lower scores on fitness tests in females. Thirty percent of males and 24% of females regularly drank at "unsafe," levels while 26% of males and 29% of females smoked. Smoking was associated with "unsafe" drinking.

CONCLUSION

Cardiovascular risk factors in 18-year-olds are related to smoking, "unsafe" drinking, and physical inactivity, particularly in females. These behaviors should be targeted in designing multimodal health promotion programs appropriate for these young adults.

Alcohol, hypertension and the cardiovascular system: a critical appraisal

Cross-sectional and longitudinal population studies have provided a considerable corpus of evidence for an inverse association between light to moderate alcohol intake and both coronary artery disease and stroke. The formulation of balanced public health advice on the basis of such studies, however, needs to take into account the full spectrum of the effects of alcohol on the cardiovascular system, particularly its equally well documented effect to increase level of blood pressure and prevalence of hypertension. In this review, the broader implications of the association of alcohol with hypertension are discussed, principally in the context of the effect of higher levels of alcohol consumption to increase ischaemic and haemorrhagic stroke, left ventricular hypertrophy, congestive cardiomyopathy, cardiac arrhythmia and sudden cardiac death.

Life style as a blood pressure determinant

In Belgium, an affluent Western European country, participation in sports, alcohol intake, and living in a working class area were identified as the life style factors with the closest associations with the blood pressure level. Obesity was another important blood pressure correlate. Sodium intake, determined from the 24 h urinary output, and smoking were not associated with blood pressure. Controlled intervention studies have proven that weight reduction, endurance training and alcohol abstinence effectively reduce blood pressure. In the light of these intervention studies, the Belgian findings and the published work highlight the potential of preventive strategies aimed at these major life style factors.

Direct and astrocyte-mediated effects of ethanol on brain-derived endothelial cells

The effects of ethanol have been studied in the central nervous system, however there exists only scarce information about the effects of ethanol on endothelial cells forming the blood-brain barrier. As some properties of brain endothelial cells are modulated by underlying astrocytes, the effect of ethanol on cerebral microvasculature might be indirect and mediated by astrocytes. To analyse this question, we added to rat brain-derived endothelial cells (rbEC) in culture either only ethanol (0, 15 and 150 mM) or ethanol conjointly with soluble factors secreted by astrocytes. Alternatively, astrocytes were exposed to ethanol and the medium was added to rbEC. The effects of treatments were evaluated on cell growth and expression of specific proteolytic markers of rbEC. The experiments showed that while the addition of ethanol alone to rbEC increased the expression of gamma-glutamyltranspeptidase and cell growth following an initial toxic effect, the most significant effects were seen when ethanol was added to rbEC together with astrocytic factors or when medium conditioned by astrocytes exposed to ethanol was added to rbEC. In particular, the expression of angiotensin converting enzyme in endothelial cells was dose-dependently increased. These results indicate that the hypertensive and toxic effects of ethanol are mediated by ethanol and soluble factor(s) secreted by astrocytes and dependent on the expression of angiotensin converting enzyme in the brain endothelium. Thus, when evaluating in vitro the effects of toxic substances such as ethanol on the cerebral endothelium, the modulating effect of cells surrounding cerebral vessels must be accounted for.

Alcohol, hypertension and cardiovascular disease--implications for management

Regular alcohol consumption raises blood pressure and in drinking populations contributes significantly to the prevalence of hypertension. The effect of alcohol is additive to that of obesity. Reduction in alcohol intake leads to a lowering of blood pressure over 1-4 weeks. Acute alcohol ingestion in the evening may lower blood pressures overnight. Heavy weekend drinking may lead to a pressor effect for the succeeding 3 to 4 days. Certain personality types or heavy job strain increase susceptibility to pressor effects of alcohol. Alcohol consumption in the range of 1-3 standard drinks a day appears to have a protective effect against coronary disease and ischaemic stroke, which may be greater in those with a higher risk of vascular disease. At higher levels of consumption the risks of haemorrhagic stroke, cardiomyopathy and hypertension deaths predominate. Moderation of alcohol consumption to no more than two standard drinks a day can be an effective means of improving blood pressure control reducing drug requirements in treated hypertensives, and avoiding drugs in mild hypertensives. Moderating alcohol and reducing excess weight have additive effects in reducing overall cardiovascular risk.

The Challenge of Hypertension to South African Health Psychology. 1. The Potential Contribution of Educational, Cognitive and Behavioural Strategies to Prevention and Treatment

This is the first of two papers on the potential contribution of health psychology to alleviating the problem of hypertension in South Africa. Educational, cognitive and behavioural strategies that can be employed as an adjunct to, or in place of, medication include: improving patients’ adherence to treatment regimens; educating and training in weight reduction, smoking cessation; healthy dietary and exercise habits; and a range of cognitive and behavioural stress management techniques. Research is reviewed, mostly from Europe and the USA, evaluating the effectiveness of these strategies, and their current status relative to the use of medication is examined.