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Biomedical subjects

W L Haskell

Publications and source records attributed to W L Haskell.

At least 91 records · Page 5Linked to original sources
PubMed1990

Smoking in older women. Is being female a 'risk factor' for continued cigarette use?

Current national data indicate that a greater percentage of women entering their fifth and sixth decades of life are current, as opposed to former, smokers, while for men the opposite pattern is present. A representative sample of 1876 men and women aged 50 to 65 years living in a northern California community were interviewed to examine factors related to gender differences in quit rates in this age group. In this well-educated community, a significantly greater percentage of women (25.6%) continued to smoke relative to men (18.6%), with a greater percentage of men reporting being former smokers. Multivariate analysis revealed educational level and marital status, rather than gender, to be significant, Independent factors associated both with current cigarette use and with successful quitting. Our data indicate that it is not being female per se, but rather the disparities in educational level and marital status that are linked with being an older woman, that are associated with continued smoking in this age group. In light of this, delivery of relevant information and support on the part of physicians and other health professionals may be of particular use to this population segment.

California↗
PubMed1990

The relationship between repressive and defensive coping styles and blood pressure responses in healthy, middle-aged men and women.

The current study explored the relationship between repressive coping and blood pressure responses at rest and during a mental challenge. One hundred and twenty healthy, middle-aged men and women completed anxiety and defensiveness measures. Subjects scoring below the median on anxiety and above the median on defensiveness were categorized as repressors; those below the median on both measures as low-anxious; those above the median on anxiety and below the median on defensiveness as moderately anxious; and those above the median on both measures as defensive moderately-anxious. As predicted, repressors showed greater systolic blood pressure reactivity in response to a mental challenge relative to the other groups (p less than 0.01). Repressors also had greater resting systolic blood pressure levels than the other groups (p less than 0.001). The findings are discussed with respect to the potential influence of this response pattern on blood pressure and other CVD risk factors and behaviors.

Adaptation, Psychological↗
PubMed1990

Effect of long-term community health education on blood pressure and hypertension control. The Stanford Five-City Project.

The Stanford Five-City Project was initiated in 1978 to evaluate the effects of a community-wide health education program on cardiovascular risk factors, including blood pressure. Two treatment cities received an education program, which used the mass media, various community-based programs, and health professionals, designed to encourage individuals to learn their blood pressure levels, stay in the care of a physician if hypertensive, achieve ideal weight, exercise regularly, and reduce dietary sodium. Physicians were encouraged to follow national hypertension treatment guidelines and were provided with a range of patient education materials. To evaluate the effect of the intervention on cardiovascular risk factors, four independent cross-sectional surveys of randomly selected households and four repeated surveys of a cohort were conducted in both treatment cities and in two of the three control cities. After 5-1/3 years of intervention, blood pressure in the treatment cities exhibited an overall decline of 7.4 and 5.5 mmHg systolic and 5.0 and 3.7 mmHg diastolic in the cohort and independent surveys, respectively. These declines produced net changes between the treatment and control cities ranging from -1.1 to -3.8 mmHg. While the magnitude of these changes is not large, the results are significant from a public health perspective because they reflect changes in the overall community.

Blood Pressure↗
PubMed1990

Energy expenditure index of walking for normal children and for children with cerebral palsy.

Energy expenditure indices (EEI) based on oxygen uptake and heart rate were used to compare the economy of walking at various speeds by normal and cerebral-palsied children. At low walking speeds, EEI values were high, indicating poor economy. At higher speeds the EEI values decreased until a range of maximum economy was reached. For normal children who were capable of walking beyond this range at higher speeds, the EEI increased again. This pattern was noted for both oxygen-uptake and heart-rate indices. Mean EEI values based on oxygen uptake and heart rate for normal children were significantly lower and occurred at faster walking speeds than values for children with cerebral palsy. EEI based on either oxygen uptake or heart rate can be used clinically to provide objective information to help evaluate the influence on gait function of surgical intervention, ambulatory aids or orthotics.

Adolescent↗
PubMed1990

Haemodynamic and ADH responses to central blood volume shifts in cardiac-denervated humans.

Haemodynamic responses and antidiuretic hormone (ADH) were measured during body position changes designed to induce blood volume shifts in 10 cardiac transplant recipients to assess the contribution of cardiac and vascular volume receptors in the control of ADH secretion. Each subject underwent 15 min of a control period in the seated posture, then assumed a lying posture for 30 min at 6 degrees head-down tilt (HDT) followed by 30 min of seated recovery. Venous blood samples and cardiac dimensions (echocardiography) were taken at 0 and 15 min before HDT, 5, 15 and 30 min of HDT, and 5, 15 and 30 min of seated recovery. Blood samples were analysed for haematocrit, plasma osmolality, plasma renin activity (PRA) and ADH. Resting plasma volume (PV) was measured by Evans blue dye and per cent changes in PV during posture changes were calculated from changes in haematocrit. Heart rate (HR) and blood pressure (BP) were recorded every 2 min. In the cardiac transplant subjects, mean HR decreased (BP less than 0.05) from 102 b.p.m. pre-HDT to 94 b.p.m. during HDT and returned to 101 b.p.m. in seated recovery while BP was slightly elevated (P less than 0.05). PV was increased by 6.3% (P less than 0.05) by the end of 30 min of HDT but returned to pre-HDT levels following seated recovery. Plasma osmolality was not altered by posture changes. Mean left ventricular end-diastolic volume increased (P less than 0.05) from 90 +/- 5 ml pre-HDT to 105 +/- 4 ml during HDT and returned to 88 +/- 5 ml in seated recovery. Plasma ADH was reduced by 28% (P less than 0.05) by the end of HDT and returned to pre-HDT levels with seated recovery. PRA was also reduced by 28% (P less than 0.05) with HDT. These responses were similar to those of six normal cardiac-innervated control subjects and one heart-lung recipient. Therefore, cardiac volume receptors are not the only mechanism for the control of ADH release during acute blood volume shifts in man.

Adult↗
PubMed1990

Differences in insulin-induced glucose uptake and enzyme activity in running rats.

To evaluate the relationship between enhanced insulin action and level of exercise training, in vivo glucose uptake was assessed in the absence of added insulin and during insulin-stimulated conditions for three activity levels of voluntarily trained rats (low 2-5 km/day, medium 6-9 km/day, high 11-16 km/day). After rats rested for 24 h and fasted overnight, glucose uptake was estimated by comparing steady-state serum glucose (SSSG) levels at low insulin (SSSI) concentrations achieved during an insulin suppression test. In the absence of added insulin, SSSI averaged approximately 20 microU/ml and glucose uptake was similar for high runners and younger weight-matched controls. However, with insulin added to sustain SSSI at approximately 35 microU/ml, SSSG was significantly reduced in all runners (P less than 0.02), with the lowest value attained in high runners. Fasting serum triglycerides were also reduced in all runners (P less than 0.05), with the lowest values seen in medium and high runners. The concentration of glycogen in liver and select skeletal muscles at the start of the study was not different between trained and control rats, suggesting that enhanced insulin-stimulated glucose uptake was not the result of lower glycogen levels. In addition, glycogen synthase and succinate dehydrogenase activities in biceps femoris muscle were only elevated for high runners, but glycogen synthase activity was not enhanced in plantaris muscle and was decreased in soleus muscle. These findings indicate that enhanced insulin-stimulated glucose uptake and reduced serum triglyceride concentrations induced in exercise-trained rats at varying activity levels are dissociated from changes in glycogen synthase and oxidative enzyme activity for skeletal muscle.

Animals↗
PubMed1990

Identifying strategies for increasing employee physical activity levels: findings from the Stanford/Lockheed Exercise Survey.

While worksite exercise programs offer a number of potential advantages with respect to increasing physical activity levels in American adults, typical participation rates remain relatively low. The purpose of this study was to explore employee preferences and needs related to physical activity programming in a major work setting in northern California. Two-thirds (399) of a randomly selected sample of employees responded to a mailed survey. Male and female employees reporting no regular aerobic activity over the past two years more strongly endorsed a number of erroneous beliefs concerning exercise, reported less support for engaging in exercise both at home and at work, and avoided even routine types of activity to a greater extent than more active individuals (p values less than 0.001). Current exercisers reported use of a greater number and variety of motivational strategies as part of their exercise program than past exercisers who were not currently active (p less than 0.001). Respondents, regardless of exercise status and age, reported preferences for moderate-intensity activity occurring away from the workplace which could be performed on one's own rather than in a group or class. Implications of the findings with respect to development of educational and behavioral programs for the current employee population are discussed.

Adolescent↗
PubMed1990

Are women using postmenopausal estrogens? A community survey.

Self-reported estrogen and progestin use in a California community was determined in 1986-87 from a telephone survey of postmenopausal women (n = 954) ages 50-65 years. Current use of hormones was reported by 32 percent; 26 percent took estrogens alone while 6 percent used estrogen + progestin. Comparisons pointed to significant social network and medical care utilization differences. Women who used estrogen therapy were younger, thinner, lived in smaller household units, and were less likely to be widowed.

Aged↗
PubMed1989

Ultrasonic tissue characterization with a real time integrated backscatter imaging system in normal and aging human hearts.

Experimental studies have shown that variation in the magnitude of integrated ultrasonic backscatter during the cardiac cycle represents acoustic properties of myocardium that are affected by pathologic processes; however, there are few clinical studies using integrated backscatter. Forty subjects without cardiovascular disease (aged 22 to 71 years, mean 41) were studied with use of a new M-mode format integrated backscatter imaging system to characterize the range of cyclic variation of integrated backscatter in normal subjects. Cyclic variation in integrated backscatter was noted in both the septum and the posterior wall in all subjects. The magnitude of the cyclic variation of integrated backscatter and the interval from the onset of the QRS wave of the electrocardiogram to the minimal integrated backscatter value were measured using an area of interest of variable size for integrated backscatter sampling and a software resident in the ultrasound scanner. The magnitude of cyclic variation was larger for the posterior wall than for the septum (6.3 +/- 0.8 versus 4.9 +/- 1.3 dB, p less than 0.01). The interval to the minimal integrated backscatter value was 328 +/- 58 ms for the septum and 348 +/- 42 ms for the posterior wall (p = NS). There was a weak correlation between the magnitude of cyclic variation of integrated backscatter and subject age for the posterior wall (r = -0.47, p less than 0.01), but this was not significant for the septum (r = -0.21) (partially because of inability to exclude specular septal echoes) and septal endocardium.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Influence of regular aerobic exercise on psychological health: a randomized, controlled trial of healthy middle-aged adults.

Although a variety of psychological benefits have been attributed to regular exercise, few experimentally controlled studies of healthy individuals currently exist. One hundred twenty healthy, sedentary, middle-aged men and women were randomly assigned to either a 6-month home-based aerobic exercise training program or to an assessment-only control condition. Adherence across the 6-month period was found by both self-report and heart rate microprocessor methods to exceed 75% in both sexes. To assess changes in a variety of psychological variables over time, a 14-item Likert rating scale was completed and returned on a biweekly basis throughout the 6-month period. Slope analyses conducted on the 11 items attaining acceptable test-retest reliability coefficients showed significant between-groups differences on the 3 items most closely associated with the actual physical changes that occurred with exercise (all ps less than .004). Implications in relation to repeated measurement of psychological changes in nonclinical populations and the determination of the relevant population-, activity-, and program-specific parameters involved are discussed.

Adaptation, Psychological↗
PubMed1989

Relation of body fatness and its distribution to cardiovascular risk factors in young blacks and whites. The role of insulin.

Persons whose body fat is distributed predominantly in the abdomen compared with the hips are at increased risk of several chronic diseases. This study examined the cross-sectional relation of percent body fat, computed from skinfold thickness, and fat distribution, measured by the waist-to-hip girth ratio, to physiologic cardiovascular risk factors in a biracial sample (blacks and whites) of young adults aged 18-30 years. The subjects were persons who were examined at baseline (1984-1986) in the Coronary Artery Risk Development in Young Adults Study in four US metropolitan areas. The two hypotheses tested were that 1) after adjusting for percent body fat, waist-to-hip girth ratio is associated with several physiologic risk factors, and 2) fasting concentrations of serum insulin partly explain such association. Percent body fat was significantly associated with all measured blood lipids, lipoproteins, apolipoproteins, uric acid, and blood pressure. Waist-to-hip girth ratio was significantly, although more weakly, associated in multivariate models with blood concentrations of triglycerides, high density lipoprotein (HDL) cholesterol, HDL2 cholesterol, apolipoproteins A-I and B, low density lipoprotein cholesterol (in women only), uric acid, and systolic blood pressure, but was not associated in either sex with total cholesterol, HDL3 cholesterol, or diastolic blood pressure. Fasting serum insulin concentrations were significantly associated with percent body fat (Pearson r = 0.45-0.53), waist-to-hip girth ratio (Pearson r = 0.18-0.27), and most of the physiologic risk factors. Inclusion of fasting insulin in multivariate models reduced, but rarely eliminated, associations between waist-to-hip girth ratio and the physiologic risk factors. These findings suggest that obese young adults, especially those with abdominal fat preponderance, carry a physiologic profile that places them at higher risk of cardiovascular disease, and that fasting insulin concentrations are only partly explanatory.

Adipose Tissue↗
PubMed1989

Variations in running activity and enzymatic adaptations in voluntary running rats.

The running behavior and biochemical markers of oxidative and glycolytic activities associated with voluntary running activity were studied in male Sprague-Dawley rats after 6 wk of training in exercise wheel cages. Twenty-four-hour recordings of running activity were used to quantify the number of individual running bouts, their duration and running speed, and the distance run per day. We then established three categories of voluntary running activity based on the mean distance run per day during the last 3 wk of training: low-activity runners averaged 2-5 km/day, medium runners 6-9 km/day, and high runners greater than 11 km/day. Each group demonstrated an intermittent, nocturnal running pattern, at relatively high intensities, with a similar mean running speed for all groups (avg approximately 45 m/min). Differences in total distance run per day were the result of variations in both the number and duration of individual running bouts. Specifically, high runners (n = 7) had 206 +/- 30 individual running bouts per 24 h, each lasting 87 +/- 7 s; medium runners (n = 7) 221 +/- 22 running bouts, lasting 47 +/- 5 s; and low runners (n = 7) 113 +/- 7 bouts, each lasting 40 +/- 7 s. Voluntary running depressed the rate of body weight gain compared with sedentary control rats, despite an increased food and water intake for all runners. Furthermore, drinking activity was temporally associated with running periods.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Exercise-training protocols for astronauts in microgravity.

The question of the composition of exercise protocols for use by astronauts in microgravity is unresolved. Based on our knowledge of physical working requirements for astronauts during intra- and extravehicular activity and on the findings from bed-rest studies that utilized exercise training as a countermeasure for the reduction of aerobic power, deterioration of muscular strength and endurance, decrements in mood and cognitive performance, and possibly for bone loss, two exercise protocols are proposed. One assumes that, during microgravity, astronaut exercise physiological functions should be maintained at 100% of ground-based levels; the other assumes that maximal aerobic power in flight can be reduced by 10% of the ground-based level. A recommended prescription for in-flight prevention or partial suppression of calcium (bone) loss cannot be written until further research findings are obtained that elucidate the site, the magnitude, and the mechanism of the changes. Hopefully these proposed exercise prescriptions will stimulate further research and discussion resulting in even more efficient protocols that will help ensure the optimal health and well-being of our astronauts.

Exercise↗
PubMed1989

Regional adiposity patterns in relation to lipids, lipoprotein cholesterol, and lipoprotein subfraction mass in men.

Anatomical adipose tissue distribution patterns are reported to relate to plasma lipids and risk of cardiovascular disease. Waist to hip girth ratios (WHR) and subscapular 10 triceps skinfold thickness ratios (STR) were compared with percent body fat and body mass index values as correlates of plasma lipids and lipoprotein cholesterol and serum lipoprotein subfraction mass by analytic ultracentrifugation in 81 sedentary middle-aged men in a typical range of adiposity. WHR was significantly and positively correlated with plasma concentrations of triglycerides, cholesterol, and low and very low density lipoprotein (LDL and VLDL) cholesterol and inversely correlated with high density lipoprotein (HDL) cholesterol. STR followed these trends, though less strongly, in relation to plasma triglycerides, VLDL cholesterol, and HDL cholesterol. Pronounced differences were found between regional adiposity patterns in their relationships to lipoprotein subfractions, as determined by analytic ultracentrifugation. WHR was negatively correlated with HDL2 (flotation rate F(1.2) 3.5-9), positively with small LDL (S.f 0-7), intermediate density lipoprotein (S.f 12-20), and VLDL (S.f 20-400), while STR correlated with larger LDL (S.f 7-12) and larger VLDL (S.f 60-400). Overall adiposity was not significantly associated with plasma lipoprotein levels after adjusting for regional adiposity patterns. Plasma sex hormone-binding globulin and percent free testosterone were associated with regional adiposity, but did not account for the correlations between WHR and lipoproteins. WHR and STR are measures of fat distribution that correlate with plasma lipoprotein profiles consistent with cardiovascular disease risk and have different relationships to lipoprotein mass subfractions.

Adipose Tissue↗
PubMed1988

Physical fitness as a predictor of cardiovascular mortality in asymptomatic North American men. The Lipid Research Clinics Mortality Follow-up Study.

Limited data are available on the relation between physical fitness and mortality from cardiovascular disease. We examined this question in a study of 4276 men, 30 to 69 years of age, whom we followed for an average of 8.5 years. Examinations at base line included assessment of conventional coronary risk factors and treadmill exercise testing. The heart rate during submaximal exercise (stage 2 of the exercise test) and the duration of exercise were used as measures of physical fitness. Men with incomplete data (n = 308) or who were using cardiovascular drugs (n = 213) were excluded from the analysis. Men who had clinical evidence of cardiovascular disease at base line (n = 649) were analyzed separately. Forty-five deaths from cardiovascular causes occurred among the remaining 3106 men. A lower level of physical fitness was associated with a higher risk of death from cardiovascular and coronary heart disease, after adjustment for age and cardiovascular risk factors. The relative risk of death from cardiovascular causes was 2.7 (95 percent confidence interval, 1.4 to 5.1; P = 0.003) for healthy men with an increment of 35 beats per minute in the heart rate during stage 2, and 3.0 (95 percent confidence interval, 1.6 to 5.5; P = 0.0004) for those with a decrement of 4.4 minutes in the exercise time spent on the treadmill. The corresponding values for death from coronary heart disease were 3.2 (95 percent confidence interval, 1.5 to 6.7; P = 0.003) and 2.8 (95 percent confidence interval, 1.3 to 6.1; P = 0.007), respectively. We conclude that a lower level of physical fitness is associated with a higher risk of death from coronary heart disease and cardiovascular disease in clinically healthy men, independent of conventional coronary risk factors.

Adult↗
PubMed1988

Effects of solid and liquid guar gum on plasma cholesterol and triglyceride concentrations in moderate hypercholesterolemia.

Guar gum is a dietary fiber reported to decrease plasma cholesterol concentration. This study investigated the effect of guar therapy in 50 men with moderately elevated plasma cholesterol who were randomized to an 8-week study of guar therapy. Three forms of guar gum were used: a medium viscosity solid or liquid form, a high viscosity liquid form or placebo. When the medium viscosity guar therapy groups were combined, 4 weeks of therapy were shown to result in a substantial reduction in total and low density lipoprotein (LDL) cholesterol of 25 mg/dl and 23 mg/dl (p = 0.035 and 0.12), respectively. The high viscosity guar group had a reduction in total cholesterol and LDL cholesterol of 37 and 30 mg/dl, respectively (p less than 0.003 and p less than 0.02). Following 8 weeks of therapy, a return toward baseline values was observed. No significant changes were demonstrated in blood chemistries, triglyceride values, total high density lipoprotein (HDL) cholesterol or the HDL2 fraction of HDL cholesterol. The effect of the solid and liquid forms of guar on plasma cholesterol reduction was similar. This study shows that a nonpharmacologic dietary additive reduces plasma total and LDL cholesterol.

Cholesterol↗