Changes in plasma high density lipoprotein cholesterol after changes in cigarette use.
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Adult↗
Biomedical subjects
W L Haskell
Publications and source records attributed to W L Haskell.
The influence of exercise training on plasma lipids and lipoproteins in health and disease.
There is a very high probability that lipoprotein metabolism plays a central role in the etiology of coronary heart disease. In sedentary persons one way to favorably alter lipoprotein metabolism and possibly delay the progression of coronary atherosclerosis is by an increase in their habitual physical activity. More physically active persons tend to have lower plasma triglycerides and very low density lipoprotein concentrations, and a greater high-density lipoprotein mass due to higher concentrations of the subfraction HDL2 and apoprotein A-I. Plasma low-density lipoprotein concentrations usually are not significantly reduced by exercise unless accompanied by weight loss, but there may be important changes in the distribution among the low-density subfractions. These exercise effects are most likely mediated by alterations in the activity of enzymes involved in the synthesis, transport and catabolism of the various lipoproteins including lipoprotein lipase, hepatic lipase and lecithin: cholesterol acyltransferase. In healthy persons as well as in patients with ischemic heart disease, diabetes and renal failure, an increase in moderate-intensity, endurance-type activity requiring an expenditure of approximately 4 MJ (1,000 kcal) per week usually produce favorable lipoprotein changes. Above this level a dose-response relationship exists, with greater changes occurring up to energy expenditures of 19 MJ (4,500 kcal) per week.
Adult↗
Frequency and clustering of nonlipid coronary risk factors in dyslipoproteinemia. The Lipid Research Clinics Program Prevalence Study.
In a defined population of 4349 men and 3398 women, we evaluated the frequency and clustering of five nonlipid coronary heart disease risk factors--obesity, hypertension, sedentary lifestyle, cigarette smoking, and alcohol consumption--in nine categorical lipoprotein phenotypes--normal, types I or V, IIA, IIB, III, IV, hypoHDL (high-density lipoprotein), hypoLDL (low-density lipoprotein), and hyperHDL. This analysis indicated that compared with the normal phenotype, nonlipid coronary risk factors tend to be more frequent and thus cluster in individuals with "high risk" phenotypes, and occur somewhat less frequently in those with "low risk" phenotypes. Thus, identification of a high-risk phenotype suggests the presence of nonlipid risk factors as well, and the clinician should be alert to this possibility. A multivariable analysis of the independent associations of each of the risk factors with the lipid and lipoprotein components that define the phenotypes suggested that several behavioral risk factors may directly affect lipid and lipoprotein levels. This observation raises the possibility that certain intervention strategies, such as weight loss, smoking cessation, and regular exercise, may favorably influence dyslipoproteinemia.
Adult↗
Physical activity and health: need to define the required stimulus.
Exercise is frequently recommended as part of a comprehensive program of prevention, treatment or rehabilitation of chronic degenerative disease. General guidelines on prescribing exercise are based more on the characteristics of exercise required to improve physical performance than on preventing disease. Most exercise regimens are evaluated according to their effect on aerobic power or endurance. Health benefits of exercise may occur in conjunction with an improvement in physical performance capacity, but some benefits appear to be achieved by exercise that normally does not lead to improved physical fitness. Health benefits may occur as a result of repeated acute responses to exercise (but without producing a training effect) and by frequent performance of low intensity exercise (inadequate for increasing fitness). Psychological benefits may also be derived by the process of exercising. The persons who benefit most from an increase in exercise are the very inactive because the detrimental health-related consequences of extreme inactivity are rapidly reversed. There is less evidence that an increase in exercise by the already active person results in significant health benefits.
Animals↗
Exercise training during long-term beta-blockade treatment in healthy subjects.
Although it is well accepted that treatment with beta-blocking drugs impairs endurance exercise capacity acutely, whether a trained state can be achieved while receiving long-term beta-blocker therapy is controversial. The apparent attenuation of training reported in some studies has given rise to the theory that adrenergic stimulation represents a unifying mechanism by which endurance training effects are produced. This theory is supported by studies of long-term beta-agonist infusions that show apparent training responses. To assess the role of beta-adrenergic stimulation produced by exercise in the development of cardiovascular training effects, 39 healthy men were assigned in a random, double-blind fashion to receive oral propranolol, atenolol or matched placebo. Drug doses were titrated individually to minimize the heart rate response to submaximal exercise (dose ranges: atenolol, 50 to 200 mg/day; propranolol, 160 to 320 mg/day). After beginning chronic drug administration, all subjects participated in an intense, supervised 6-week exercise training program (5 days/week, 45 min/day, at least 75% peak heart rate). Adherence to training was monitored by daily supervision; compliance to the medication regimen was assessed by weekly pill counts, medication diaries and plasma drug assay. Maximal exercise testing was performed before and after training. Peak oxygen consumption increased significantly with training in all 3 groups, whether comparisons were made in the presence or absence of medication. The magnitude of change in oxygen consumption did not differ between groups (F = 0.12, p greater than 0.88). Similarly, peak work rate and duration of work increased in all 3 groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Medically directed at-home rehabilitation soon after clinically uncomplicated acute myocardial infarction: a new model for patient care.
Medically directed at-home rehabilitation was compared with group rehabilitation which began 3 weeks after clinically uncomplicated acute myocardial infarction (AMI) in 127 men, mean age 53 +/- 7 years. Between 3 and 26 weeks after AMI, adherence to individually prescribed exercise was equally high (at least 71%), the increase in functional capacity equally large (1.8 +/- 1.0 METs) and nonfatal reinfarction and dropout rates equally low (both 3% or less) in the 66 men randomized to home training and the 61 men randomized to group training. No training-related complications occurred in either group. The low rate of reinfarction and death (5% and 1%, respectively) in the study as a whole, which included 34 patients with no training and 37 control patients, reflected a stepwise process of clinical evaluation, exercise testing at 3 weeks and frequent telephone surveillance of patients who underwent exercise training. Medically directed at-home rehabilitation has the potential to increase the availability and to decrease the cost of rehabilitating low-risk survivors of AMI.
Adult↗
Relationship of exercise, oral contraceptive use, and body fat to concentrations of plasma lipids and lipoprotein cholesterol in young women.
To investigate the relationship of exercise and oral contraceptive use to plasma lipids and lipoproteins, a cross-sectional study was designed to compare lipid levels in 96 exercising and non-exercising women who used or did not use oral contraceptives. Exercisers had significantly lower plasma triglyceride concentrations and low-density/high-density lipoprotein ratios than non-exercisers after adjustment for differences in pill type distribution between groups. Women using progestin-dominant pills had significantly lower plasma triglyceride and high-density lipoprotein concentrations and significantly higher low-density/high-density lipoprotein ratios compared with women using estrogen/progestin-balanced pills. As body fat was significantly associated with both pill type and physical activity, it is unclear how much of these lipoprotein differences were due to body fat, exercise, or pill use. Regular physical activity together with reduced body fat partially compensated for plasma lipoprotein differences associated with oral contraceptive use.
Adipose Tissue↗
Coronary heart disease and risk factor modification. Is there a threshold?
Modification of coronary heart disease risk factors may play an important role in the control and alteration of the atherosclerotic process. The amount of modification necessary to obtain beneficial results is a controversial issue. Review of epidemiologic studies and recent arteriographic investigations allows for the approach to the issue of threshold levels of modification that may be required prior to obtaining some benefit. Serum lipoproteins appear to play a central role in the atherosclerotic risk factor relationship. On the basis of current evidence, clinical aims are suggested for coronary heart disease risk factor modification in order to assist in obtaining optimal health goals.
Adult↗
Cardiovascular abnormalities in the athlete: recommendations regarding eligibility for competition. Task force V: Ischemic heart disease.
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Coronary Disease↗
Modification of plasma cholesterol through exercise. Rationale and recommendations.
Until relatively recently, clinical information regarding plasma lipoproteins and their association with human atherosclerosis had been based on epidemiologic evidence obtained from cross-sectional studies or prospective studies that used clinical events as end points. Authorities have cautioned against the interpretation of these results to imply that drug therapy be used to alter the high-density lipoprotein (HDL) fraction of total cholesterol. Several recent investigations strongly suggest that decreasing the low-density lipoprotein fraction of total cholesterol and increasing the HDL fraction may alter the progression of atherosclerosis. Appropriate exercise may be a viable tool to assist in elevating plasma HDL levels.
Adult↗
Physical activity assessment methodology in the Five-City Project.
Previous measures of physical activity for epidemiologic studies were considered inadequate to meet the needs of a community-based health education trial. Therefore, new methods of quantifying the physical activity habits of communities were developed which are practical for large health surveys, provide information on the distribution of activity habits in the population, can detect changes in activity over time, and can be compared with other epidemiologic studies of physical activity. Independent self-reports of vigorous activity (at least 6 metabolic equivalents (METs) ), moderate activity (3-5 METs), and total energy expenditure (kilocalories per day) are described, and the physical activity practices of samples of California cities are presented. Relationships between physical activity measures and age, education, occupation, ethnicity, marital status, and body mass index are analyzed, and the reliabilities of the three activity indices are reported. The new assessment procedure is contrasted with nine other measures of physical activity used in community surveys.
Adolescent↗
The Stanford Five-City Project: design and methods.
The Stanford Five-City Project is a large experimental field study of community health education for the prevention of cardiovascular disease. It will provide data on fundamental questions in cardiovascular disease epidemiology, communication, health education, behavior change, and community organization, and will also test the ability of a potentially cost-effective program to prevent cardiovascular disease at the community level. This paper describes the purposes, hypotheses, design, and methods of the Five-City Project as a reference for future papers describing results. It is hypothesized that a 20% decrease in cardiovascular disease risk will lead to a significant decline in cardiovascular disease event rates in two treatment communities compared with three reference communities as a result of a six-year intervention program of community-wide health education and organization. Risk factor change will be assessed through four surveys of independent samples and in a repeatedly surveyed cohort. Cardiovascular disease event rates will be assessed through continuous community surveillance of fatal and nonfatal myocardial infarction and stroke.
Adolescent↗
Assessment of habitual physical activity by a seven-day recall in a community survey and controlled experiments.
Assessment of habitual physical activity in epidemiologic and health education studies has been difficult. A seven-day physical activity recall interview was developed and administered in a community health survey, a randomized clinical trial, and two worksite health promotion programs during 1979-1982. These studies were conducted in several populations in California, Texas, Pennsylvania, and New Jersey. Energy expenditure estimates from the physical activity recall conformed to expected age- and sex-specific values in the cross-sectional community survey. Estimates of energy expenditure were also congruent with other questions on physical activity and job classification. In a randomized, one-year exercise trial, the physical activity recall detected increases in energy expenditure in the treated group and was positively associated with miles run during training (p less than 0.05). Changes in energy expenditure were associated with changes in maximal oxygen uptake (VO2max (r = 0.33, p less than 0.05) and body fatness (r = -0.50, p less than 0.01) at six months, and in high density lipoprotein-cholesterol (r = 0.31, p less than 0.05) and triglyceride (r = -0.41, p less than 0.01) at one year. The physical activity recall detected significant (p less than 0.01) increases in energy expenditure in treatment groups in two worksite health promotion projects. These data suggest that the physical activity recall provides useful estimates of habitual physical activity for research in epidemiologic and health education studies.
Adolescent↗
Associations of resting heart rate with concentrations of lipoprotein subfractions in sedentary men.
In major prospective studies it has been reported that high heart rate at rest predicts the development of coronary heart disease (CHD) or cardiovascular disease (CVD) in men, but the mechanisms producing these relationships are unknown. Since lipoprotein levels contribute strongly to the risk of CHD and CVD, we examined the relationship of resting heart rate to plasma concentrations of high-density (HDL), low-density (LDL), and very low-density (VLDL) lipoproteins, apolipoprotein (apo) A-I and A-II, and serum concentrations of lipoprotein subfractions in 81 men to determine if atherogenic lipoproteins could potentially induce the reported association of heart rate with development of CHD or CVD. The significant (p less than or equal to .05) Spearman's correlations for resting heart rate vs HDL2 mass (rs = -.24), HDL3 mass (rs = -.40), HDL cholesterol (rs = -.36), apo A-I (rs = -.29), triglycerides (rs = .31), VLDL cholesterol (rs = .24), VLDL mass (rs = .27), and LDL mass of Sof 0-7 subfraction (rs = .30) lend support to our hypothesis of lipoprotein-induced relationships of CHD with heart rate. The correlations for resting heart rate vs triglycerides, HDL cholesterol, HDL3 mass, VLDL mass, and LDL mass of Sof 0-7 subfraction remain significant when adjusted for adiposity, age, smoking habits, diet, and physical fitness as measured by maximum aerobic power (VO2 max) or submaximal heart rate during a graded exercise test.
Age Factors↗
Metabolism of substrates: diet, lipoprotein metabolism, and exercise.
The major classes of serum lipoproteins have been shown to be differentially affected not only by dietary factors but also by levels of physical activity. Individuals engaging in relatively higher amounts of physical activity tend to have lower levels of low-density lipoprotein cholesterol (LDL-C) and very-low-density lipoprotein cholesterol (VLDL-C) and higher levels of high-density lipoprotein cholesterol (HDL-C) than their sedentary counterparts. However, higher levels of physical activity are also associated with lower adiposity and elevated caloric intake, two factors that themselves have independent roles in the regulation of lipoprotein levels. Changes in adiposity appear to be responsible for some, but not all, of the lipoprotein change associated with exercise. A study in which 14 sedentary, middle-aged men engaged in a progressive running program over 2 years showed increased HDL-C and decreased LDL-C, both considered antiatherogenic. Adiposity, expressed as percent body fat, decreased during the study whereas caloric intake, notably in the form of carbohydrates, increased. Elevated physical activity levels alter the relationships among adiposity, dietary intake, and lipoproteins that prevail in the sedentary state.
Adipose Tissue↗
Changes in rest and exercise myocardial perfusion and left ventricular function 3 to 26 weeks after clinically uncomplicated acute myocardial infarction: effects of exercise training.
The effects of exercise training on exercise myocardial perfusion and left ventricular (LV) function in the first 6 months after clinically uncomplicated acute myocardial infarction (AMI) were assessed in 53 consecutive men aged 55 +/- 9 years. Symptom-limited treadmill exercise with thallium myocardial perfusion scintigraphy and symptom-limited upright bicycle ergometry with equilibrium gated radionuclide ventriculography were performed 3, 11 and 26 weeks after AMI by 23 men randomized to training and 30 randomized to no training. Peak cycle capacity increased in both groups between 3 and 26 weeks (p less than 0.01), but reached higher levels in trained than in untrained patients (803 +/- 149 vs 648 +/- 182 kg-m/min, p less than 0.01). Reversible thallium perfusion defects were significantly more frequent at 3 than at 26 weeks: 59% and 36% of patients, respectively (p less than 0.05), without significant inter-group differences. Values of LV ejection fraction at rest, submaximal and peak exercise did not change significantly in either group. The increase in functional capacity, i.e., peak treadmill or bicycle workload, that occurred 3 to 26 weeks after infarction was significantly correlated with the increase in peak exercise heart rate (p less than 0.001), but not with changes in myocardial perfusion or LV function determined by radionuclide techniques. Changes in myocardial perfusion or LV function do not appear to account for the improvement in peak functional capacity that occurs within the first 6 months after clinically uncomplicated AMI.
Coronary Circulation↗
The effect of cessation and resumption of moderate alcohol intake on serum high-density-lipoprotein subfractions. A controlled study.
High-density lipoproteins (HDL) in plasma may be divided into two subfractions: less dense HDL2, the concentration of which appears to be negatively associated with coronary heart disease, and more dense HDL3, which is reportedly unrelated to coronary disease. Alcohol consumption correlates with both reduced coronary heart disease and increased plasma HDL cholesterol concentrations; however, the relation of moderate alcohol intake to HDL2 and HDL3 is obscure. To study the effect of alcohol on these HDL subfractions, we randomly assigned 24 men who were moderate drinkers to an abstention group (n = 12) or a control drinking group (n = 12). After six weeks, concentrations of HDL cholesterol and HDL3 mass were decreased in abstainers but not in drinkers (P less than or equal to 0.05), whereas HDL2 mass was unchanged. Resumption of drinking increased the levels of HDL cholesterol and HDL3 mass (P less than or equal to 0.05) without affecting HDL2 mass. These data suggest that the association of alcohol with coronary disease is not mediated by increases in plasma HDL2 levels. Furthermore, the HDL3 fraction may not be "inert" with respect to coronary heart disease, or the association of alcohol with coronary disease may operate through mechanisms unrelated to HDL.
Adult↗
Exercise-induced changes in plasma lipids and lipoproteins.
Men and women who participate in vigorous endurance-type exercise generally have plasma lipid and lipoprotein profiles consistent with lower risk for coronary heart disease. The major differences from matched physically inactive controls appear to be a lower plasma triglyceride concentration and greater high-density lipoprotein mass, due to increased levels of the subfraction HDL2 and apoprotein A-I. Plasma low-density lipoprotein cholesterol concentration is less likely to be lower than in the inactive controls. Exercise training studies suggest a lower threshold--of around 1,000 kcal per week of endurance-type exercise at moderate intensity--seems to be required to produce plasma lipid or lipoprotein changes. Above this level, dose-response relationship exists, with greater changes occurring up to an expenditure of 4,500 kcal per week. From the limited data available, it appears more difficult to change the plasma lipoprotein concentration in women by exercise training than in men. Modification of activity of enzymes involved in triglyceride and cholesterol synthesis, transport, and catabolism most likely mediates these exercise-induced changes.
Apoproteins↗