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Biomedical subjects

W L Haskell

Publications and source records attributed to W L Haskell.

At least 55 records · Page 3Linked to original sources
PubMed1994

Effects of intensive multiple risk factor reduction on coronary atherosclerosis and clinical cardiac events in men and women with coronary artery disease. The Stanford Coronary Risk Intervention Project (SCRIP).

BACKGROUND: Recent clinical trials have shown that modification of plasma lipoprotein concentrations can favorably alter progression of coronary atherosclerosis, but no data exist on the effects of a comprehensive program of risk reduction involving both changes in lifestyle and medications. This study tested the hypothesis that intensive multiple risk factor reduction over 4 years would significantly reduce the rate of progression of atherosclerosis in the coronary arteries of men and women compared with subjects randomly assigned to the usual care of their physician. METHODS AND RESULTS: Three hundred men (n = 259) and women (n = 41) (mean age, 56 +/- 7.4 years) with angiographically defined coronary atherosclerosis were randomly assigned to usual care (n = 155) or multifactor risk reduction (n = 145). Patients assigned to risk reduction were provided individualized programs involving a low-fat and -cholesterol diet, exercise, weight loss, smoking cessation, and medications to favorably alter lipoprotein profiles. Computer-assisted quantitative coronary arteriography was performed at baseline and after 4 years. The main angiographic outcome was the rate of change in the minimal diameter of diseased segments. All subjects underwent medical and risk factor evaluations at baseline and yearly for 4 years, and reasons for all hospitalizations and deaths were documented. Of the 300 subjects randomized, 274 (91.3%) completed a follow-up arteriogram, and 246 (82%) had comparative measurements of segments with visible disease at baseline and follow-up. Intensive risk reduction resulted in highly significant improvements in various risk factors, including low-density lipoprotein cholesterol and apolipoprotein B (both, 22%), high-density lipoprotein cholesterol (+12%), plasma triglycerides (-20%), body weight (-4%), exercise capacity (+20%), and intake of dietary fat (-24%) and cholesterol (-40%) compared with relatively small changes in the usual-care group. No change was observed in lipoprotein(a) in either group. The risk-reduction group showed a rate of narrowing of diseased coronary artery segments that was 47% less than that for subjects in the usual-care group (change in minimal diameter, -0.024 +/- 0.066 mm/y versus -0.045 +/- 0.073 mm/y; P < .02, two-tailed). Three deaths occurred in each group. There were 25 hospitalizations in the risk-reduction group initiated by clinical cardiac events compared with 44 in the usual-care group (rate ratio, 0.61; P = .05; 95% confidence interval, 0.4 to 0.9). CONCLUSIONS: Intensive multifactor risk reduction conducted over 4 years favorably altered the rate of luminal narrowing in coronary arteries of men and women with coronary artery disease and decreased hospitalizations for clinical cardiac events.

California↗
PubMed1994

J.B. Wolffe Memorial Lecture. Health consequences of physical activity: understanding and challenges regarding dose-response.

The Guidelines for Exercise Training initially developed by the American College of Sports Medicine in 1978 and updated in 1990 have served as the foundation for most recommendations regarding physical activity program design for the general public. These guidelines have proven to be very useful by providing a specific regimen for enhancing aerobic capacity and body composition. As data supporting a causal link between increased activity or fitness and health status have evolved, questions have been raised about potential limitations of these guidelines for promoting physical activity to increase the health status of sedentary adults. The major issues have involved the necessity to achieve the values for each of the program parameters, especially the intensity, duration, and frequency of exercise, in order to improve health status. To address these issues, a paradigm shift from exercise training to promote physical fitness to physical activity to promote health has been introduced. This new paradigm is based on the results from numerous studies indicating that a generally active life style is associated with better health and performance and greater longevity and a certain set of assumptions, yet to be fully tested. The following article provides some background leading to the development of the ACSM guidelines and presents some of those issues we understand and some we do not regarding the characteristics of daily physical activity or exercise training that are likely to improve the physical health status of sedentary persons.

Chronic Disease↗
PubMed1994

The efficacy and safety of exercise programs in cardiac rehabilitation.

Physical activity performed by patients with coronary heart disease is a two-edged sword. A number of biological changes produced by regular exercise may reduce the risk of future cardiac events, while the increase in cardiac work produced by this same exercise can predispose the patient to sudden cardiac death. Data from observational studies as well as randomized clinical trials demonstrate a lower cardiac mortality rate for men participating in exercise rehabilitation programs vs nonparticipants. Overall, exercise program participants appear to experience a reduction of approximately 25% in cardiac and all-cause mortality, but no single study has provided definitive results. During medically supervised exercise, the risk of cardiac death based on reports of programs in the United States is approximately one event in every 60,000 participant-hours of exercise. At this rate, a typical rehabilitation program that has 95 patients exercising 3 h.wk-1 could expect a sudden cardiac death during an exercise session once every 4 yr. No data have been published on the morbidity or mortality benefits or risks of home-based exercise or for women participants. Also, the contribution of continuous electrocardiographic monitoring to the safety of exercise training of cardiac patients is yet to be defined.

Adult↗
PubMed1993

Associations between changes in physical activity and risk factors for coronary heart disease in a community-based sample of men and women: the Stanford Five-City Project.

Aerobic exercise training studies involving volunteers generally result in an improved cardiovascular risk factor profile. Little is known, however, about associations between physical activity change and risk factor change in a more representative sample, such as a community. This investigation evaluated correlations between a composite physical activity change score and change in cardiovascular risk factors from 1979 to 1985 in the cohort sample of the Stanford Five-City Project. Men (n = 380) and women (n = 427) between the ages of 18 and 74 years were evaluated for change in self-reported physical activity and change in total cholesterol, high density lipoprotein cholesterol (HDL cholesterol), systolic blood pressure, resting pulse rate, and body mass index (weight (kg)/height (m)2). For men, improvement in the composite physical activity score significantly correlated with an increase in HDL cholesterol (r = 0.14, p = 0.005) and decreases in body mass index (r = -0.16, p = 0.001) and estimated 10-year coronary heart disease risk score (r = -0.10, p = 0.056). For women, improvement in the physical activity score was associated with changes in HDL cholesterol (r = 0.11, p = 0.028) and resting pulse rate (r = -0.15, p = 0.001). These data demonstrate that an increase in physical activity over 5 years is favorably associated with changes in major cardiovascular disease risk factors in men and women and support the public health efficacy of community-wide promotion of physical activity.

Adolescent↗
PubMed1993

Daily physical activity levels in congestive heart failure.

To determine the level of daily physical activity routinely performed by patients with congestive heart failure (CHF) and the ability of clinical and laboratory assessments of function to predict peak daily activity levels, 45 patients with CHF were evaluated in the laboratory and during 2 days of usual activity. Subjects performed symptom-limited treadmill exercise tests with respiratory gas analysis and wore a Vitalog activity monitor with continuous measurement of heart rate and body motion. Mean maximal oxygen uptake for this sample was 16.8 ml/kg/min. Peak daily physical activity involved walking on a flat surface (44%), or general activities (housework/yardwork, 42%). Most subjects were asymptomatic (49%) during daily physical activity, 22% noted dyspnea, 16% fatigue and 13% sore muscles/joints. Perceived intensity of peak daily physical activity (mean = 4.19, SD = 2.21) was similar to perceived exertion (mean = 3.73, SD = 1.37) reported at ventilatory threshold measured during treadmill exercise testing. Subjects may control their peak daily physical activity to minimize symptoms experienced. It was further observed that current methods of assessing functional capacity in these patients were inadequate for estimating the peak level of daily activity. In conclusion, daily physical activity levels are low in patients with congestive heart failure and a gap exists between exercise capacity and actual performance of daily physical activity.

Aged↗
PubMed1993

A comparison of oxygen pulse and respiratory exchange ratio in cerebral palsied and nondisabled children.

Energy expended while walking is increased for children with cerebral palsy compared to nondisabled children. This study compared oxygen uptake, oxygen pulse, and the respiratory exchange ratio (RER) in children with cerebral palsy and nondisabled children walking on a treadmill. Resting oxygen uptake and oxygen pulse values were not different in the two groups. At a given walking speed, oxygen uptake, oxygen pulse, and RER were higher for subjects with cerebral palsy. At a given level of submaximal oxygen uptake, oxygen pulse and RER values were not different in subjects with cerebral palsy compared to nondisabled children. It was concluded that the cardiorespiratory response to walking at submaximal level of work is not significantly different for children with cerebral palsy.

Adolescent↗
PubMed1993

Association of lipoprotein subclass distribution with use of selective and non-selective beta-blocker medications in patients with coronary heart disease.

The relationship of beta-blocker drug use to plasma low density lipoprotein-cholesterol (LDL-C), lipoprotein mass distribution, (LDL, Sf0-12), intermediate density lipoproteins (IDL, Sf12-20), very low density lipoproteins (VLDL, Sf20-400), and high density lipoproteins (HDL, F(1.2)0-9) were examined in 206 men with coronary heart disease. Thirty-three used non-selective (NSEL), 49 used selective (SEL), and were compared to 124 who used no beta-blockade (NoBB). No significant between group differences were seen for potentially confounding variables. LDL and IDL mass, total cholesterol and LDL-cholesterol were not significantly different between groups. HDL-C was significantly lower in both NSEL (P < 0.005) and SEL (P < 0.01). NSEL and SEL had significantly lower HDL mass (P < 0.005 and P < 0.005) and SEL (P < 0.01 and P = 0.06), and HDL3 mass (P < 0.01 and P < 0.05). VLDL mass was significantly higher (P < 0.02) only in NSEL. Small LDL (Sf0-7) was not significantly different between groups and large LDL (Sf7-12) was significantly lower in NSEL (P < 0.05) and SEL (P < 0.05). LDL peak Sf was significantly lower in both NSEL (P < 0.005) and SEL (P < 0.02) compared to NoBB. Despite the lack of differences in levels of LDL-cholesterol, beta-blocker use is associated with a significant difference in the distribution of larger, more buoyant to smaller, more dense LDL particles. Reduced HDL levels in subjects on beta-blockade therapy are associated with reductions in both HDL2 and HDL3 subclasses.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1993

Physical activity in young black and white women. The CARDIA Study.

Total physical activity scores, based on level of participation in 13 types of activities for 2658 black and white women aged 18 to 30 years were examined in relation to demographic, health behavior, psychosocial, and obesity data to compare levels of physical activity and determine reasons for disparities between blacks and whites. Black women had lower scores than white women--geometric mean of 178 (95% confidence interval (CI): 167, 189) versus 318 (95% CI: 305, 332). After controlling for age and education, physical activity was associated with physical activity level before high school, life events score, John Henryism, and competitiveness in both groups. In white women only, it was associated with alcohol intake and need to excel, and negatively associated with number of children, number of cigarettes smoked, and fatness. Race remained a predictor of physical activity after controlling for each variable. Relationships between physical activity and age, education, cigarette smoking, and life events differed significantly by race. Black women had lower physical activity levels than white women, which may contribute to higher rates of obesity and coronary heart disease. Racial differences in physical activity remain largely unexplained by the factors examined.

Adult↗
PubMed1993

Effects of differing intensities and formats of 12 months of exercise training on psychological outcomes in older adults.

The 12-month effects of exercise training on psychological outcomes in adults ages 50-65 years were evaluated. Ss (N = 357) were randomly assigned to assessment-only control or to higher intensity group, higher intensity home, or lower intensity home exercise training. Exercisers showed reductions in perceived stress and anxiety in relation to controls (p < .04). Reductions in stress were particularly notable in smokers. Regardless of program assignment, greater exercise participation was significantly related to less anxiety and fewer depressive symptoms, independent of changes in fitness or body weight (p < .05). It was concluded that neither a group format nor vigorous activity was essential in attaining psychological benefits from exercise training in healthy adults.

Adult↗
PubMed1993

Endurance exercise and health-related quality of life in 50-65 year-old adults.

Health-related quality of life was evaluated in relation to endurance exercise over the prior year for 194 previously sedentary, healthy men and women aged 50-65 using a posttest-only design. Three exercise regimens were studied that varied in format (class-based vs home-based) and intensity (higher vs lower). In all regimens, subjects who participated more had better physical health 12 months after program initiation (p values < .05); no differences were observed in general psychological well-being. Extent of participation, rather than format or intensity of exercise, was associated with better physical health in this population.

Aged↗
PubMed1993

Metabolic and behavioral covariates of high-density lipoprotein cholesterol and triglyceride concentrations in postmenopausal women.

OBJECTIVE: To determine predictors of high-density lipoprotein cholesterol (HDL) and triglyceride (TG) concentrations in postmenopausal women. DESIGN: Cross-sectional study. SETTING: Clinical research facility. PARTICIPANTS: One hundred twenty-seven healthy, relatively sedentary, postmenopausal women not on estrogen replacement, mean age 57 years. MEASUREMENTS: Alcohol intake, cigarette smoking, aerobic fitness (VO2max), body mass index (BMI), percent body fat, waist-hip ratio, lipids and lipoproteins, fasting plasma glucose (FPG), and insulin (FPI) concentrations. RESULTS: In univariate analyses, HDL was significantly (P < 0.05) inversely related to BMI, waist-hip ratio, smoking, FPG, and FPI, and directly related to VO2max and alcohol intake. Triglycerides were related directly to BMI, waist-hip ratio, percent body fat, FPG, and FPI, and inversely to VO2max. In stepwise multiple regressions, BMI, waist-hip ratio, alcohol, smoking, and FPG were significantly associated with HDL (R2 for the model = 0.43). Addition of TG to these models reduced relations of BMI and waist-hip ratio, but not the other variables, to insignificance. For triglycerides, waist-hip ratio, alcohol, smoking, FPG, and FPI were significant predictors (R2 = 0.33). VO2max and percent body fat did not contribute to any model. CONCLUSIONS: Obesity, abdominal obesity, smoking, alcohol intake, and measures of carbohydrate metabolism predict HDL and triglyceride concentrations in postmenopausal women.

Alcohol Drinking↗
PubMed1993

Coronary artery size and dilating capacity in ultradistance runners.

BACKGROUND: Increases in coronary artery size and dilating capacity have been observed in some animals after endurance training, and at autopsy, active men appear to have enlarged epicardial coronary arteries. This cross-sectional study was designed to test the hypothesis that highly trained endurance runners have larger epicardial coronary arteries and greater dilating capacity than inactive men. METHODS AND RESULTS: The subjects, ages 39-66 years, included 11 male volunteers who had participated in ultradistance running during the past 2 years and 11 physically inactive men who had been referred for arteriography but had no visible coronary artery disease. The internal diameter of the proximal segments of each major epicardial coronary artery was measured before and after nitroglycerin administration using a computer-based quantitative arteriographic analysis system. Measurements also included maximal oxygen uptake, plasma lipoprotein concentrations, body composition, and cardiac mass by echocardiography. Before nitroglycerin, the sum of the cross-sectional areas for the proximal right, left anterior descending, and circumflex arteries was not different for the runners and the inactive men: 22.7 +/- 4.79 versus 21.0 +/- 7.97 mm2 (p = 0.57), respectively. However, the increase in the sum of the cross-sectional area for the proximal right, left anterior descending, and circumflex arteries in response to nitroglycerin was greater for the runners (13.20 +/- 4.76 versus 6.00 +/- 3.02 mm2; p = 0.002). Left ventricular mass index (152 +/- 21 versus 116 +/- 41 g/m2; p < 0.05) but not left ventricular mass (284 +/- 40 versus 246 +/- 91 g; p = 0.22) was significantly greater for the runners. Among the runners, dilating capacity was positively correlated with aerobic capacity and negatively related to adiposity, resting heart rate, and plasma lipoprotein concentrations. CONCLUSIONS: Highly trained, middle-aged endurance runners demonstrated a significantly greater dilating capacity of their epicardial coronary arteries in response to nitroglycerin compared with inactive men. The causes of this greater dilating capacity and its clinical significance need to be determined.

Adult↗
PubMed1993

Compendium of physical activities: classification of energy costs of human physical activities.

A coding scheme is presented for classifying physical activity by rate of energy expenditure, i.e., by intensity. Energy cost was established by a review of published and unpublished data. This coding scheme employs five digits that classify activity by purpose (i.e., sports, occupation, self-care), the specific type of activity, and its intensity as the ratio of work metabolic rate to resting metabolic rate (METs). Energy expenditure in kilocalories or kilocalories per kilogram body weight can be estimated for all activities, specific activities, or activity types. General use of this coding system would enhance the comparability of results across studies using self reports of physical activity.

Energy Metabolism↗
PubMed1993

Simultaneous measurement of heart rate and body motion to quantitate physical activity.

None of the various methods used to measure habitual physical activity over days, weeks, or years in the general population have yet proven entirely satisfactory. A major problem is that no "gold standard" exists for the validation of various questionnaires, logs, or diaries that can be used in large sample population studies. Attempts have been made to accurately measure the activity profile by using heart rate or various motion sensors or accelerometers, but each approach has had significant limitations. The availability of new solid state recording techniques and computer-based analytic and display procedures now makes it possible to simultaneously record heart rate and body movement continuously for days and to combine the analysis of these data using customized software. Preliminary evaluation of this concept of simultaneous recording and analysis of heart rate and body motion via movement sensors on an arm and leg were conducted in 19 men. Subjects performed a variety of exercises in the laboratory during which heart rate, leg motion, arm motion, and oxygen uptake were recorded. Various issues regarding the prediction of energy expenditure from heart rate and body movement independently and in combination were evaluated. The results demonstrate that the accuracy of estimating oxygen uptake during a wide range of activities is improved when individualized heart rate--oxygen uptake regressions are used and heart rate and body movement are analyzed simultaneously rather that separately.

Adult↗
PubMed1993

Cigarette smoking and submaximal exercise test duration in a biracial population of young adults: the CARDIA study.

Symptom-limited, graded exercise treadmill testing was performed by 4,968 white and black adults, ages 18-30 yr, during the baseline examination for the Coronary Artery Risk Development in Young Adults (CARDIA) study. Compared with nonsmokers, the mean exercise test duration of smokers was 29-64 s shorter depending on race/gender group (all P < 0.001), but mean duration to heart rate 130 (beats.min-1) ranged from 20-50 s longer (P < 0.05). In each race/gender group, test duration to heart rates up to 150 was 15-35 s longer (P < 0.05) in smokers than in nonsmokers after adjustment for age, sum of skinfolds, hemoglobin, and physical activity score. The mean maximum heart rate was lower in smokers than in nonsmokers (difference ranging from 6.7 beats.min-1 in white men to 11.2 beats.min-1 lower in black women, P < 0.001), although maximum rating of perceived exertion was nearly identical in smokers and nonsmokers. Chronic smoking appears to blunt the heart rate response to exercise, so that exercise duration to submaximal heart rates is increased even though maximal performance is impaired. This may result from downloading of beta-receptors caused by smoking. Smoking status should be considered in the evaluation of physical fitness data utilizing submaximal test protocols, or else the fitness of smokers relative to nonsmokers is likely to be overestimated.

Adolescent↗