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PubMed1990

The effect of exercise on energy intake and body composition in overweight women.

Twelve moderately overweight women with mild obesity were studied to determine the effect of exercise on nutrient intake and body composition. The women, 16 to 42 percent above desired body weight (BW) and 30 to 41 percent body fat, rotated through three 18-day treatment periods: no exercise (NO-EX), moderate duration exercise (M-EX), and long duration exercise (L-EX). Daily exercise was prescribed to increase energy expenditure by 12.5 (M-EX) or 25 percent (L-EX) of energy intake required for BW maintenance during baseline. Diets were self-selected from a variety of conventional foods, and intake was monitored. Exercise did not affect quantity of energy intake or macronutrient composition of diets during the treatment periods. Energy and carbohydrate intakes tended to be higher in response to M-EX and L-EX compared to NO-EX during the last 5-day interval of the treatment periods, but these trends were not statistically significant. Exercise did affect BW and fat-free mass (FFM); mean FFM values were 49.3, 49.7 and 50.8 kg at the end of NO-EX, M-EX and L-EX, respectively (P = 0.017). Body fat mass (FM) was not consistently affected by exercise. It appears that exercise affects FFM but has no consistent effect on nutrient intake in mildly obese women who are choosing food intake from a variety of foods.

Adipose Tissue↗

PubMed1990

Patient selection and outcomes for out-of-hospital births in one family practice.

This paper reports a study of the pregnancies followed to delivery in one family medicine group practice that offered a choice of childbirth settings. Those choosing out-of-hospital birth (OHB) were a self-selected group of highly motivated couples interested in natural childbirth or desiring to minimize the cost of pregnancy care. Of 790 singleton pregnancies followed to term, 71 (9.0%) planned home births, 510 (64.6%) planned clinic births, and 209 (26.5%) planned hospital births. Of those planning clinic or home birth, 73% gave birth outside the hospital as planned (44 at home and 379 in the clinic), 81 (14%) changed plans prenatally and gave birth in a local hospital, 46 (8%) were transferred to the local hospital intrapartum, and 29 (5%) were referred to tertiary care. Primiparas who initially chose OHB were more likely than multiparas to give birth in a hospital (46% vs 16%). Controlling retrospectively for obstetric risk and parity, there were few differences in outcome between local hospital and out-of-hospital births. The observed rates of serious complications for OHB were low, but overall, 27% of those initially considered candidates for birth outside the hospital required a change to a higher level of care. For primiparas initially planning clinic or home birth, discriminant analysis revealed five variables that together might have improved the prediction of the eventual decision for hospital delivery in 46%. Clinical pelvimetry was the most powerful variable, in keeping with the finding that most intrapartum transfers were for arrests of labor. The results also suggest that financial factors and other features of the physician-patient relationship influenced clinical decision making.

Adult↗

PubMed1990

Control of body mass transfer as a function of speed of ascent in sit-to-stand.

The purpose of this study was to test the hypothesis that a progressive variation in the speed of ascent would result in differences in the horizontal and vertical motions of the body center of mass (CM) and in the governing impulse-momentum relationship. A motion analysis system and two force platforms were used to examine the STS task among 10 healthy adults at each of three self-selected speeds. As the speed of ascent became faster, a progressively earlier time to the maximum vertical linear momentum and an increase in its magnitude occurred. In contrast, a relatively constant time to the maximum linear momentum, which was also the time when the propulsive impulse became the braking impulse, was found in the horizontal direction, and the propulsive impulse showed a disproportionately (1:3) smaller increase from slow to fast speeds than its vertical counterpart. The relative invariance in the horizontal motion suggested that different neuromuscular control strategies may have been employed in the horizontal and vertical directions to accomplish the different tasks of balance control in one direction and changing the gravitational potential energy in the other direction.

Adult↗

PubMed1990

Oxygen uptake and heart rate responses to treadmill and water running.

The relationship between heart rate (HR) and oxygen uptake (VO2) was assessed during treadmill running and during running-like motions in water without ground support. Athletes self-selected easy, moderate and hard efforts during water running. While there was a linear relationship between HR and VO2 in both exercise conditions, there was considerable between-subject variability of the slope and intercept of the linear regressions. These data are taken to indicate that HR for a given VO2 during water compared to land running is influenced in large part by the skill of the athlete in the water running activity.

Adult↗

PubMed1990

Influence of concentric resistance training on concentric and eccentric strength.

This study investigated the effects of isokinetic concentric training on isokinetic concentric and eccentric torque outputs. Sixteen female subjects (mean age in years +/- SE = 21 +/- 1) were randomly assigned to either a training or a control group. Concentric and eccentric torques of the right knee extensors were assessed at 1.05rad.s-1 using a KinCom isokinetic dynamometer system. Each test consisted of a set of four maximal concentric and four maximal eccentric contractions of the knee extensors. The peak and average torques for each contraction were calculated using the computer software supplied by the KinCom manufacturer. On a separate day, after abstaining from heavy exercise for at least 12 hours, a single cross-sectional image of the thigh at midfemur was obtained using computer tomography (CT) scanning. From this image, cross-sectional area of the quadriceps femoris group was calculated using the computer software associated with the General Electric 9800 CT Scanning System. Training group subjects trained three days weekly for six weeks on a Cybex II+ isokinetic dynamometer, completing five sets of ten maximal effort knee extensions at an angular velocity of 1.05rad.s-1. Each set of exercise was separated by two minutes of self-selected recovery. Torque outputs were monitored daily to ensure that adequate recovery was provided between sets of exercise, and to document changes in strength as the program progressed. Significant (p less than .01) increases in peak and average concentric torque (11% and 12%, respectively), peak and average eccentric torque (18% and 21%, respectively), and muscle cross-sectional area (3.2%) were observed for training group subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1989

A circadian rhythm of population behavior in Gonyaulax polyedra.

Like other flagellates, Gonyaulax polyedra exhibits diurnal vertical migration and pattern formation. Shape and size of the aggregations depend on container type, light intensity, and cell density. In Petri dishes, cells form oval "swarms"; within these, cells move downward in the highly dense center and rise up at the periphery. We have investigated the daily rhythm of this swarming activity in Petri dishes illuminated from the side, using time-lapse video recordings. At night, a "lawn" of cells forms at the bottom of the dish toward the light source (independent of light intensity). Before dawn, cells rise toward the surface and aggregate in swarms. The daily vertical migration occurs independent of light direction and intensity. The diurnal swarms, however, form every day at the same location within the dish, at a distance from the light that depends on light intensity, indicating a self-selection of light intensity. In constant light and temperature and with negligible vertical nutrient differences, all aspects of the rhythm continue to oscillate for up to 3 weeks, when the rhythm of the population becomes desynchronized. Under cycles of bright white-dim red light (WR), cell entrain to WR 10:10 but free run in WR 8:8 and shorter cycles, showing relative coordination (von Holst, 1939) to the driving light cycle. They also entrain to the 24-hr multiple of WR 6:6. Under nonentrained conditions, swarming activity is still influenced by light changes, and in spite of the apparent free run, the phasing of the averaged activity varies systematically with different T-cycle frequencies.

Animals↗

PubMed1989

Evidence for spread of the human immunodeficiency virus epidemic into low prevalence areas of the United States.

Reports of an increased proportion of AIDS cases occurring in small and medium-sized cities suggest that the HIV epidemic may be spreading into locations that were previously characterized by their low HIV antibody prevalences. Studying the question of the geographic spread of the HIV infection epidemic (rather than the AIDS epidemic) has been difficult largely because most serial seroprevalence data have been gathered from cohorts of high risk individuals (e.g., homosexual/bisexual cohorts) in New York City, San Francisco, and other geographically circumscribed areas. The U.S. military applicant HIV screening data were used in the current report to examine rates and 24 month temporal trends in geographic areas characterized by their HIV endemicities. The data examined concern the seven most populous states and four hyperendemic metropolitan areas located within those states (New York City, Miami, Houston, and San Francisco). In the nonepidemic regions, seroprevalence rates increased among black and white applicants. In the four epidemic urban areas, only young black applicants had higher HIV seroprevalence rates during the second 12 month period. Six of the seven nonepidemic regions had positive HIV seroprevalence trends, and these trends were significant in Florida, California, Texas, Illinois, and Ohio. The increases in these regions were greater for young blacks (30% excess for year 2 vs. year 1) compared to young whites (12% excess for year 2 vs. year 1). These data provide evidence of birth year specific increases in seroprevalence over time occurring in presumed low HIV prevalence areas. These increases cannot be due to, but are observed in spite of, biases associated with increasing self-selection over time.

Acquired Immunodeficiency Syndrome↗

PubMed1989

Restoration to normal body composition by VLCD: a comparison of post obese and lean subjects questions BMI 25 as diet limit.

Body composition was assessed in naturally lean female subjects who never had need to diet. At BMI 21-22 their body weight distribution of 75 per cent FFM and 25 per cent fat was compared with subjects who had dieted below BMI 25 by various conventional self-selected diets; subjects who had dieted to BMI 21-22 by VLCD and subjects who were dieting with VLCD but were still above BMI 25. These body composition studies support values of BMI 22-22 as a better estimate of desirable weight in women than BMI 25. At BMI 21-22 the distribution of body weight between fat and FFM of post VLCD dieters matches that of normal lean women.

Body Composition↗

PubMed1989

[Varicosities of the lower extremities in workers in positions requiring continuous standing or sitting positions].

An epidemiological study of the prevalence of varicose veins of lower extremities was carried out in an industrial population of 434 men and 345 women. A statistically significant (p less than 0.05) association between the varicose disease and duration of work was found in all groups of workers, except for women sitting at work. Decrease in the prevalence of varicose veins after 20 years of employment may be explained at least partly, by the factor of self-selection in the industry. However, there was no difference in the prevalence of varicose veins between workers standing and those sitting at work.

Female↗

PubMedDate not supplied

Effects of music and imagery on physiologic and self-report of analogued labor pain.

Two studies were conducted to examine the effects of music on analogued labor pain using volunteer nulliparous subjects who were randomly assigned to treatment groups (n = 10 per group). Assessments of the treatments were made in a 1-hour session involving twenty 80-second exposures to a laboratory pain stimulus patterned to resemble labor contractions. In the first experiment, it was hypothesized that subjects listening to easy-listening music would report lower pain ratings and cardiovascular responses than subjects listening to rock music, self-selected music, or a dissertation (placebo-attention) and subjects in a no-treatment control group. No significant group effects were found; significant time effects were found for heart rate, systolic and diastolic blood pressure. Subjects spontaneously reported using imagery as a pain reduction technique. In the second study a combination of music and imagery was examined by randomly assigning subjects to one of five groups: self-generated imagery with music (SIM), guided imagery with music (GIM), self-generated imagery without music (SI), guided imagery without music (GI), or no-treatment control. Again, no significant group effects were obtained. Significant time effects were obtained for heart rate, systolic and diastolic blood pressure.

Adult↗

PubMed1989

Quality of care in family practice: does residency training make a difference?

As the proportion of physicians who enter residency training in family practice steadily increases, so does the need to evaluate the impact of their training and postgraduate education on the quality of care in their practices. We audited the practices of 120 randomly selected family physicians in Ontario, who were separated into four groups: nonmembers of the College of Family Physicians of Canada (CFPC), members of the CFPC with no certification in family medicine, certificated members without residency training in family medicine and certificated members with residency training in family medicine. The practices were assessed according to predetermined criteria for charting, procedures in periodic health examination, quality of medical care and use of indicator drugs. Generally the scores were significantly higher for CFPC members with residency training in family medicine than for those in the other groups, nonmembers having the lowest scores. Patient questionnaires indicated no difference in satisfaction with specific aspects of care between the four groups. Self-selection into residency training and CFPC membership may account for some of the results; nevertheless, the findings support the contention that residency training in family medicine should be mandatory for family physicians.

Adult↗

PubMed1989

Public cholesterol screening: motivation for participation, follow-up outcome, self-knowledge, and coronary heart disease risk factor intervention.

We used a mailed questionnaire and telephone interviews with 1717 shopping center screenees whose total serum cholesterol was greater than 200 mg/dl. Our specific aim was to assess the subjects' motivations for participation in cholesterol screening, their follow-up outcome, their self-knowledge, and any coronary heart disease risk factor intervention. Of 1717 questionnaires mailed, 507 (30%) were returned; 64 of 100 subjects randomly selected for telephone interview could be contacted, and 61 were interviewed. Responses to the questionnaire and telephone interview were congruent, indicating little self-selection response bias. Before the cholesterol screening, 50% and 67% of questionnaire and telephone interview subjects knew their cholesterol levels. The nine most commonly cited reasons for cholesterol screening participation were: a desire to "watch" health (72%), convenience (70%), low cost (64%), to recheck previously measured total cholesterol (54%), publicity (34%), curiosity (30%), a relative with premature coronary heart disease (27%), the subjects' obesity (26%), and a relative's high cholesterol level (25%). As a result of cholesterol screening, 65% and 63% of questionnaire and telephone interview subjects, respectively, followed up with their doctors; 67% and 56%, respectively, had total cholesterol remeasured, but 17% and 18%, respectively, were told to "do nothing." At their doctors' follow-up, 74% and 51% of questionnaire and telephone interview respondents, respectively, began a low-saturated fat, low-cholesterol diet; 10% and 15% started taking a cholesterol-lowering drug. As a result of cholesterol screening, 76% and 85% of questionnaire and telephone interview subjects, respectively, changed their diets; 78% and 84% lowered their dietary cholesterol intakes, 62% and 74% increased their fiber intakes, 49% and 57% tried to lose weight, and 44% and 43% increased their exercise. Of questionnaire subjects, 94% thought that by lowering cholesterol, coronary heart disease risk could be reduced; 95% had become more aware of cholesterol in the last 5 years. Of telephone interview subjects, 91% concluded that cholesterol screening had motivated them to reduce cholesterol levels. Public cholesterol screening is convenient, inexpensive, facilitates self-knowledge about cholesterol, stimulates follow-up, and motivates physician and subject-guided dietary changes to reduce cholesterol levels and coronary heart disease risk.

Adult↗

PubMed1989

[Physiological responses to heat and effort and complaints of hyperperspiration].

The sensation of hyperperspiration is a common complaint in hot, humid climates. 54 men and 20 women, 18-47 years old, who had this complaint and 27 male control subjects were examined at rest and after 1 hour of mild exercise (40W) under conditions of heat stress (37 degrees C, 50% relative humidity). During exposure to heat rectal and skin temperatures and heart rate were measured every 15 min. Sweat rate was calculated for the entire period of exposure and sweat gland density was measured at 0, 60 and 120 min. Only insignificant deviations from baseline values were noted at rest. During exercise the sweat rate of the men with the complaint was within normal limits and similar to that of the control men (285 +/- 75 ml/m2 vs 272 +/- 48). Matching for age and V02 max revealed no significant differences in physiological responses of men with and those without the complaint. Women with the complaint lost 25-30% less fluid (226 +/- 67 ml/m2) and their concentrations of active sweat glands were lower than in either of the male groups. 2 men and 1 woman with the complaint and 1 control lost 400-425 ml/m2 during exercise, the upper limit of normal. Only 1 subject showed hyperperspiration (855 ml/m2) during the test. All physiological parameters examined in these 5 subjects were within normal limits. It is concluded that the complaint of hyperperspiration in our self-selected group is basically a subjective feeling and has no pathological basis. None of the subjects was heat intolerant.

Adult↗

PubMed1989

Correlates of certification in family medicine in the billing patterns of Ontario general practitioners.

There is conflicting evidence as to whether physicians who are certified in family medicine practise differently from their noncertified colleagues and what those differences are. We examined the extent to which certification in family medicine is associated with differences in the practice patterns of primary care physicians as reflected in their billing patterns. Billing data for 1986 were obtained from the Ontario Health Insurance Plan for 269 certified physicians and 375 noncertified physicians who had graduated from Ontario medical schools between 1972 and 1983 and who practised as general practitioners or family physicians in Ontario. As a group, certificants provided fewer services per patient and billed less per patient seen per month. They were more likely than noncertificants to include counselling, psychotherapy, prenatal and obstetric care, nonemergency hospital visits, surgical services and visits to chronic care facilities in their service mix and to bill in more service categories. Certificants billed more for prenatal and obstetric care, intermediate assessments, chronic care and nonemergency hospital visits and less for psychotherapy and after-hours services than noncertificants. Many of the differences detected suggest a practice style consistent with the objectives for training and certification in family medicine. However, whether the differences observed in our study and in previous studies are related more to self-selection of physicians for certification or to the types of educational experiences cannot be directly assessed.

Canada↗

PubMed1986

Ethanol drinking by vervet monkeys (Cercopithecus pygerethrus): individual responses of juvenile and adult males.

Unrestricted access of vervet monkeys to a palatable solution of ethanol resulted in chronic intake or abstinence. Self-selected dose averaged 4.42 g/kg body mass/day. Growth of juveniles was not grossly affected. In plasma, chronic ethanol intake was associated with lower average K and Cl values, increased gamma glutamyl transpeptidase in some adults, and higher average total cholesterol. Neither hepatic histology nor haematology were affected by chronic ethanol intake.

Age Factors↗

PubMed1989

Energy intake and dietary macronutrient content in women with anorexia nervosa and volunteers.

This study was designed to compare the dietary intakes of patients with anorexia nervosa and normal controls. Twenty-four patients hospitalized for treatment of anorexia nervosa were compared with 10 normal controls. Patients ate a self-selected diet and maintained their admission weight to within 1.0 kg during this period (19 +/- 3 days). Food chosen by each subject was weighed before and after meals, and intake was determined to be the difference. Intakes of food energy, protein, fat, and carbohydrate were calculated. Patients were closely monitored to ensure that no disposal of food occurred. Patients with anorexia nervosa had a mean daily energy intake of 1,017 +/- 54 kcal (mean +/- SEM), significantly lower than the mean energy intake for controls (1,651 +/- 108 kcal). Similarly, mean intakes of macronutrients (41 +/- 4 gm protein, 34 +/- 2 gm fat, and 136 +/- 9 gm carbohydrate) were significantly lower for patients than for controls (68.5 +/- gm protein, 65 +/- 6 gm fat, and 204 +/- 13 gm carbohydrate). However, when protein, fat, and carbohydrate were assessed as a percent of total calories, there were no significant differences between patients and controls. There were also no significant differences in calories consumed per kilogram body weight. Underweight patients with anorexia nervosa who maintain their weight on an unrestricted hospital diet have energy intake per kilogram body weight and dietary macronutrient content indistinguishable from those of normal women.

Adult↗

PubMed1989

Relation of family physician or specialist care to obstetric interventions and outcomes in patients at low risk: a western Canadian cohort study.

To determine the relation of family physician or specialist care to intrapartum interventions and outcomes, we carried out a historical cohort study of 1456 obstetric patients at low risk admitted between Nov. 15, 1984, and Mar. 15, 1986, to a western Canadian teaching hospital. The patients were classified as being at low risk on admission by means of chart review. Family physicians and specialists were found to have similar rates for most of the interventions measured, although the interventions for which significantly different rates were found suggest a less interventionist style of intrapartum care by family physicians. There were no significant differences in maternal or neonatal outcomes except for a higher proportion of infants weighing less than 2500 g among primigravid women cared for by family physicians compared with those under the care of specialists. Self-selection of physician specialty by patients resulted in differences in the demographic characteristics of the two patient populations. The findings support the continued involvement of family physicians in the provision of obstetric care.

Adolescent↗

PubMed1979

Potential effect of demographic and other variables in studies comparing morbidity of breast-fed and bottle-fed infants.

Comparing the morbidity of breast-fed and bottle-fed infants is confounded by inherent differences in breast-feeding and bottle-feeding mothers and their infants. Self-selection introduces complex variables encompassing much more than milk source used for infant feeding. Reasons for selecting breast or bottle feeding relate to demographic, socioeconomic, educational, ethnic, cultural, and psychological factors, as well as maternal and infant physical and emotional health. Many of the differences in the maternal populations may affect infant care practices, access to medical care, and infant health status. Studies published to date have not quantified these confounding effects and other potential biases in comparing morbidity to breast- and bottle-fed infants and the relationship between milk source and incidence of infantile disease remains in question. There is need for more cautious use of the available data and investigators must seek ways to design future studies to take into account the differences between breast-feeding and bottle-feeding mothers that affect both reported and actual infant morbidity.

Bottle Feeding↗