Assessment, prevalence, and cardiovascular benefits of physical activity and fitness in youth.
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Biomedical subjects
Publications and source records attributed to G Heath.
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This article reviews seven community-based programs for prevention of cardiovascular disease and their effects on blood cholesterol levels and saturated fat intake. In two programs, cholesterol levels were reduced more in the intervention area than in the reference area. In two other programs, cholesterol increased less in the intervention area than in the reference area. In one program, cholesterol levels initially fell in the intervention group and increased in the reference group; after the first 4 years, the levels also started to increase in the intervention group. The final two programs reduced cholesterol equally in both groups. Only two programs reported on the intake of saturated fats; in both, intake of saturated fat was reduced more in the intervention area than in the reference populations. In one program area, total intake of fat was reduced more than in the reference area. Published data do not allow us to draw conclusions regarding which components of the programs were most important. These studies show that the average blood cholesterol level can be affected in a general population.
Data from the Hispanic Health and Nutrition Examination Survey conducted from 1982 to 1984 were analyzed for the sensitivity, specificity, and positive and negative predictive value of self-reported hypertension in 5195 Hispanics of both sexes between the ages of 18 and 74 years. On the basis of a hypertension definition of 140/90 mmHg or of the use of antihypertensive medications, overall sensitivity of self-reported hypertension was 56% for Mexican-Americans, 71% for Cuban-Americans and 72% for Puerto Ricans. Sensitivity was higher among women, among the obese, and among those with access to a regular place for medical care; increased with increasing age; and decreased with education and the time interval since last medical visit. Independent associations for sensitivity were noted for sex, body mass index (BMI), and time interval since last medical visit among Mexican-Americans; and for time interval since last medical visit and for being divorced or separated for Cuban-Americans. Overall positive predictive value reached 49% among Mexican-Americans, 53% among Cuban-Americans, and 39% among Puerto Ricans. Raising the hypertension-threshold to 160/95 mmHg tended to increase the sensitivity but reduced the positive predictive value.
The purpose of this study was to examine the degree to which changes in muscular activity modify tactile perceptual asymmetries. In two experiments subjects were presented with a series of pairs of random shapes to the fingers of each hand. Their task was to detect the occurrence of a previously learnt target shape. Pressing on to the shape was the only movement allowed and other types of motor activity, particularly tracing movements, were not permitted. Across experimental conditions subjects were required to change the pressure and hence muscular effort used to press upon the shape. A left-hand advantage was found across all experimental conditions and its size did not change when subjects were required to press either firmly or lightly upon the shapes. This result was also found when subjects were required to apply uneven pressure between the hands. One-half of the subjects also performed the experimental conditions following instructions to use imagery. This produced an enhancement of right-hand performance on the task with a loss of the left-hand advantage. The results suggest that observed tactile perceptual asymmetries, while unaffected by changes in muscular effort, are easily overridden by higher-order cognitive and motor processes.
We studied the effect of exercise training (ET) on systolic time intervals (STI) in 13 patients with coronary artery disease (CAD). All patients trained for at least 10 months. They exercised three times/week at 50% to 70% of maximal oxygen uptake (VO2max) for the initial 3 months and at least four times/week for approximately 50 minutes at 70% to 90% of VO2max thereafter. A significant training effect was documented by an increase in VO2max from 26.0 +/- 4.3 to 37.2 +/- 5.8 ml/kg/min (p less than 0.01), a lower heart rate (HR) at rest, and a lower blood pressure and HR during submaximal work. The indices of total electromechanical systole (QS2I) and left ventricular ejection time (LVETI) did not change. However, pre-ejection period index (PEPI) decreased from 137 +/- 9 msec to 129 +/- 9 msec (p less than 0.01). PEP/LVET decreased from 0.373 +/- 0.028 to 0.342 +/- 0.032 (p less than 0.01). Left ventricular end-diastolic dimension and posterior wall thickness, measured echocardiographically, were increased after training. We conclude that exercise training may improve myocardial performance in some patients with CAD.
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Training with resistant exercises has been proved to be beneficial for patients of ischemic cardiopathy. This kind of training increases working capacity, provided the exercise is maintained in the necessary threshold to avoid starting a chest angina. Nevertheless, there is no clear evidence of an increase in the blood flooding of the myocardio, the left ventricle function or the heart electric stability as a consequence of the said training. It's our opinion that the principal reasons for this lack of evidence are: a) insufficient research, b) the existence of technical difficulties for developing certain phases of the necessary research, and maybe that, c) some exercise programs are not sufficiently long and intense and to induce myocardial adaptation. The purpose of this study is to determine if a long program of physical exercise training could produce a better blood irrigation and ventricular function as well as restore the electric stability. This approach to the problem is justified by the recent finding of adequate methods which really and definitely answer these questions with the results obtained through properly controlled physical exercise.