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Biomedical subjects

R J Shephard

Publications and source records attributed to R J Shephard.

At least 325 records · Page 18Linked to original sources
PubMed1981

Exercise compliance and the prevention of a recurrence of myocardial infarction.

Exercise compliance (three exercise sessions per week) has been shown to have a favorable effect upon prognosis (P less than 0.001) in 610 "post-coronary" patients followed for an average of 36.5 months. This cannot be explained entirely by mutual correlation of the data with other health habits (as indicated by smoking behavior) or disease severity (as indicated by angina, exercise-induced ST-segmental depression, cardiac enlargement, or ventricular aneurysm). Stratification of the data shows that in almost all categories of subject, sustained physical activity is associated with a five-fold improvement in the odds ratio for both fatal and non-fatal recurrences of the infarction.

Exercise Therapy↗
PubMed1981

Fitness program participation: its effect on worker performance.

The effects of an employee fitness program upon absenteeism and productivity were investigated in a controlled trial involving two large offices. During the six-month experimental program, the test company developed substantial gains of fitness. However self-reports and supervisor evaluations showed small and relatively similar gains of productivity, with reduction of absenteeism at both test and control companies. Further studies on a large scale are warranted. The presently observed changes probably reflect (1) sample attenuation, (2) seasonal trends, and (3) a "Hawthorne" effect. If the last factor is substantiated, employee fitness programs may be of economic interest, despite the nonspecific nature of the resultant gains in productivity.

Adult↗
PubMed1981

Reasons for dropout from exercise programs in post-coronary patients.

The dropout rate in the 7-yr Ontario Exercise Heart Collaborative Study of post-coronary men engaged in exercise programs was examined in order to determine possible contributing factors. A questionnaire pertaining to psychosocial and program-related variables was distributed to 728 subjects who were previously assigned randomly on the basis of four prognostic risk factors (occupation, personality, hypertension, and angina) into exercise groups: low intensity exercise (LIE), and high intensity exercise (HIE). Comparisons of answers by the 639 respondents (266 dropouts; 373 compliers) were made initially by chi-square analysis to determine significant categories of questions and, subsequently, by a logistic transform to determine the specific questions which related significantly to the dropout rate. It was found that three main categories were associated with a high dropout rate: convenience aspects of the exercise center, perceptions of the exercise program, and family/lifestyle factors. These three main categories should be carefully considered when designing and implementing potential compliance-improving strategies for secondary prevention exercise programs entailing long-term adherence.

Angina Pectoris↗
PubMed1981

Cardio-respiratory fitness and muscular strength in the lower-limb disabled.

The International Year of the Disabled Person has focused increased attention upon the fitness status of the wheelchair-confined. Review of the world literature indicates that cardio-respiratory assessment has been based relatively equally upon forearm cycling or wheelchair ergometry; each of these techniques have particular advantages. The evaluation of muscular strength and endurance has received much less attention, in spite of the importance of these factors to the daily function of the lower-limb impaired. Also neglected in the past has been the psychological correlates of spinal cord trauma and their possible interaction with attitudes concerning physical activity. Fitness is often poor in the disabled, and everyday wheelchair propulsion does not seem to provide a sufficient stimulus for cardio-respiratory adaptation. Additional training in the form of forearm pedalling, exercises with weights or wheelchair sports may provide an effective means of improving cardio-respiratory fitness and muscle function. Indeed, research on disabled athletes has suggested that with persistent sports participation or fitness conditioning many wheelchair-confined individuals can make a relatively good physiological and psychological adaptation.

Hemodynamics↗
PubMed1980

Effects of a 6-month industrial fitness programme on serum lipid concentrations.

The serum lipid profile (total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides) has been studied in 98 men and 158 women before and 6 months after introducing an employee fitness programme. Over this period, the sample sorted itself into 4 sub-groups (non-participants, drop-outs, high adherents, and low adherents). The high-adherents attended 2--3 30-min physical activity classes per week over the 6-month study, progressing to 15--17 min of aerobic activity per session, with significant gains of predicted maximum oxygen intake, and reductions of body fat. Nevertheless, there were few "favourable" changes of lipids that could be related to the physical activity sessions. A decrease of total cholesterol (mainly in the women) was unrelated to the changes of maximum oxygen intake, and occurred equally in non-participants and high adherents. High adherent women showed a decrease of LDL cholesterol, but this also was almost matched by changes in non-participants, while the main response of HDL cholesterol was a decrease in non-participants and drop-outs rather than an increase in high-adherents. It is concluded that if data are collected while subjects are in energy balance and persisting with their activity, a programme of the intensity practical in an employee fitness class has little impact upon blood lipids.

Adult↗
PubMed1980

Some factors influencing serum lipid levels in a working population.

Life-style variables (perceived fitness, excess body mass, percent fat, lean mass, predicted maximum oxygen intake, cigarette consumption, alcohol consumption, use of contraceptive medication) have been related to the lipid profile (serum triglycerides, total cholesterol, HDL and LDL cholesterol) in a sizeable volunteer population of Toronto office-workers. Multivariate analysis demonstrates an independent positive association of age with total cholesterol, HDL and LDL cholesterol, and (in women only) a weak negative association with triglycerides. Much of the fitness effect is related to body fat, which is positively correlated with triglycerides and (in the men only) with total and LDL cholesterol, but is negatively related to HDL cholesterol. However, maximum oxygen intake per unit of body mass shows a small independent association with triglycerides, total cholesterol (women only) and LDL cholesterol. Cigarette smoking bears an independent relationship to triglycerides, HDL cholesterol and (in women only) LDL cholesterol. Alcohol consumption is independently related to high values for total and LDL cholesterol, but is also related to high HDL cholesterol readings. While multivariate analysis allows for the inter-relationship of smoking habits, alcohol consumption, and the various fitness measurements, it cannot prove cause and effect. Nevertheless, the potential improvement of lipid profile associated with (i) abstinence from cigarettes, (ii) a 4% reduction of body fat, and (iii) avoidance of contraceptive medication is sufficient to warrant experimental trial of such a change in life-style.

Adult↗
PubMed1980

The switching point from nasal to oronasal breathing.

The switching point from nasal to oronasal breathing during incrementally graded submaximal exercise was determined in 30 (14 M, 16 F) healthy adult volunteers. Nasal airflow was measured by a pneumotachograph attached to a nasal mask. Oral airflow was determined as the difference between nasal airflow and total pulmonary airflow, the latter being measured by a head-out exercise body plethysmograph. The airflow and pressure signals were sampled every 20 msec by a micropressor, which calculated respiratory volumes and nasal work of breathing, and produced an on-line print-out. Twenty of the 30 subjects (normal augmenters) switched from nasal to oronasal breathing at submaximal exercise of 105.0 W (SD = 30.1), four subjects (mouth breathers) breathed habitually oronasally, five subjects (nose breathers) persistently breathed through the nose only, and one subject showed no consistent nose/mouth breathing pattern. In normal augmenters, the onset of oronasal breathing (VE 35.3 +/- 10.81 . min-1) was quite consistent individually, but varied considerably between inividuals without showing a significant sex difference. The factors most closely related to the switching point were rating of perceived exertion of breathing and nasal work of breathing.

Adolescent↗
PubMed1980

The current status of the Canadian home fitness test.

The current status of the Canadian Home Fitness Test is reviewed. This simple procedure was originally conceived for the mass testing of fitness levels and for home use as a motivational tool in exercise programmes. The test is carried out on a double 8 inch step (such as a domestic staircase) at an age and sex-specific rhythm set by a long-playing record. Fitness is assessed from a combination of test-duration and the radial or carotid pulse count immediately following exercise. Use of the procedure by upwards of 500,000 Canadians is reviewed in relaltion to its safety, validity and practicality. To date, there have been no serious complications. In home use, there is inevitably limited precision, although with practice subjects can learn to count their pulse rate and step in time to the music; further, the test seems well received, achieving its prime objective of stimulating an interest in physical activity and endurance fitness. When the procedure is carried out by a paramedical worker, with e.c.g. recording of the exercise heart rate, it provides at least as good an estimate of maximum oxygen intake as other sub-maximal procedure; the main area of current controversy is interpretation of abnormal stress e.c.g. records, and it is suggested this problem could be resolved by the appropriate training and certification of interested family physicans and paramedical workers.

Adolescent↗
PubMed1980

Stroke volume during recovery from upright bicycle exercise.

A CO2 rebreathing method has been modified to allow nonsteady-state measurements of cardiac output during and after recovery from upright bicycle ergometer exercise. Data obtained on 10 healthy men who continued loadless pedaling for 4 min following a progressive exercise bout to 70% of maximum oxygen intake showed a rapid recovery of heart rate. In contrast, there was an early 29% increase of stroke volume and 216 s after exercise the stroke volume was still larger than the final exercise reading. It appears that if venous return is facilitated, the metabolic needs of recovery plus the small cost of loadless pedaling are met by maintaining stroke volume rather than heart rate.

Adult↗
PubMed1980

Physical fitness, respiratory symptoms and lung function.

Lung volumes (FVC1, FEV1.0 and peak flow) were measured in 403 men and 561 women volunteers for fitness testing, using the SRL automated spirometer system. Average scores for this population were 5--10% higher than predicted from age, height and sex using either the formulae inherent in the SRL computer or standards proposed by Anderson et al. [1968] for the Toronto population; existing standards may thus underestimate respiratory potential. Lung function data showed a dose-dependent decrease within the category of cigarette smokers, but there was no significant difference between average results for smokers and non-smokers. Multivariate analysis showed significant contributions of lean mass and obesity to the overall description of lung volumes; however, effects were not large enough to justify incorporation of such variables into routine prediction equations. Positive responses to the respiratory section of the Cornell Medical Index were in several instances associated with below expected lung volumes. The most consistent response was to the question 'do you suffer from asthma?' Although the average effect was significant, the magnitude of response (10--20%) would have been overlooked in individual testing; this suggests that there may be more scope for pulmonary screening through the improvement of questionnaires than through the purchase of expensive electronic spirometers.

Adolescent↗
PubMed1980

Recurrence of myocardial infarction. Observations on patients participating in the Ontario Multicentre Exercise-Heart Trial.

The circumstances attending a fatal or non-fatal recurrence of myocardial infarction have been analysed for participants in the Ontario Multicentre Exercise-Heart Trial. After an average of some 20 mth observations, 51 of the 751 participants had sustained a recurrence (rate 4.07 per 100 participant years). Some 24% of episodes were closely associated with various types of physical activity, and a further 22% noted vigorous exercise (sometimes of an unusual nature) a few hours previously. Exercise-related episodes were associated with poor programme compliance and ST segmental depression during test exercise, but were unrelated to the prescribed regimen (high or low intensity physical activity). Continuing smoking and a history of recent angina were associated with a risk of recurrence; both were seen less commonly with recurrence in high intensity exercisers than in their low intensity exercise counterparts. Exercise-induced ST segmental depression was associated with a higher frequency of fatal recurrences in high than in low intensity exercisers (P less than 0.05); there may thus be a 'high-risk' subgroup for whom vigorous exercise is contraindicated, and the existence of such a group could confound therapeutic trials of exercise-centred rehabilitation.

Clinical Trials as Topic↗
PubMed1980

"Post-coronary" rehabilitation, body composition, and recurrent infarction. An analysis of data from the Ontario Exercise-Heart Collaborative Study.

Changes in body composition have been studied in patients with ischemic heart disease over a 2-year period, commencing 3--12 months after a well-documented myocardial infarction. Findings have been related to diet, the exercise undertaken (random allocation of volunteers to high intensity and low intensity exercise programmes) and the recurrence of myocardial infarcation. When first recruited, subjects were not much more obese than other middle-aged men. In contrast with experience in the "healthy" middle-aged exerciser, compliance of postcoronary patients with the required regimen was uninfluenced by body build. Over the 2 years of observation, both high and low intensity exercise groups showed small losses of fat and gains of lean mass. It is suggested that these changes reflect responses to dietary regulation and an increase of physical activity rather than a specific effect of the prescribed effort; the potential advantage of the high intensity exercise programme was lost through a larger food intake. Patients who sustained a recurrence of their infarction had an average percentage of body fat, but a low excess weight and lean mass; although isometric exercise is not frequently implicated in the recurrence of an infarction, the development of muscle mass might be advantageous to patients who must continue to work in occupations that demand sustained isometric muscular activity.

Body Composition↗
PubMed1980

Exercise for postcoronary patients: an assessment of infrequent supervision.

Forty-nine patients who had been attending a regular weekly physician-supervised exercise program for a year or more following a myocardial infarction were transferred to an experimental regimen based on a personal activity prescription, reinforced by attendance at the physician-supervised exercise class once every 8 weeks. Data were compared with the responses of 31 patients who continued to attend the standard rehabilitation program. Ten of the 49 experimental patients showed a deterioration of cardiorespiratory fitness over the ensuing year. Of the remaining 39, 23 who had already reached a training plateau sustained their condition, while 16 showed small continuing gains of aerobic power. The infrequently supervised program proved safe, but its therapeutic effectiveness is doubtful; relative to the patients receiving standard treatment, gains of aerobic power were small, and there was some deterioration of the exercise electrocardiogram over the year of study.

Body Composition↗
PubMed1980

Factors influencing recruitment to an occupational fitness program.

Factors influencing participation in an employee fitness program have been studied in a group of 535 early recruits for a Health Fitness Center established at the headquarters office of a larger corporation. The overall participation rate (20% of eligible staff with convenient access to the facility) was much as in previous reports. Interest was relatively equal in men and in women. Typical recruits were middle-aged non-smokers who had previously been active elsewhere. Men had an above average maximum oxygen intake and muscle strength, but were also somewhat overweight and fat. Women were closer to their actuarial ideal weight, but had relatively lower levels of cardiorespiratory and muscular fitness than the men. Program acceptability factors (traveling time, hours of work, and cost) had little effect on participation. Subjects perceived that they were active for health, fitness, competition (men), and appearance (women). General and specific health beliefs were well-developed, but bore surprisingly little relationship to health practices and outcomes. It is thus argued that the shaping of attitudes by trial of an exercise program may be a more effective tactic for increasing exercise participation than general campaigns designed to change attitudes and values.

Adult↗
PubMed1980

Some characteristics of participants in an industrial fitness programme.

A controlled study has allowed an investigation of several hypotheses relating to initial recruitment and continued participation in an employee fitness programme. Following initial physiological and psychological testing, attendance records show that the staff of the experimental company sorted themselves into four categories (non-participants, drop-outs, low adherents, and high adherents). Parallel observations were made at a second, comparable company where there was no employee fitness programme. Exercise classes met three times per week for 30 minutes of rhythmic calisthenics and endurance-type activities. Continued participation was favoured by a short stature, but perhaps because of gentle progression of intensity, there was no selective loss of obese subjects. A below average strength in high adherent men was related to their short stature. Participation was favoured by an interest in activity as the release of tension on the scale of Kenyon (women). Negative factors were a low score for personal and social factors on the scale of Holmes & Rahe (men), a recent health change (women), dissatisfaction with pay on the Job Description Index of Smith et al. (male non-participants, female drop-outs), and an interest in activity as Games of Chance (women). In the men, "Type A" score on the questionnaire of Friedman and Rosenman was highest in those with infrequent participation, but not in drop-outs; this possibly reflects a real time conflict among upper executives. Body image (Kenyon and McPherson scales), manifest anxiety (Taylor Scale) and reported health (Cornell Medical Index) were unrelated to participation in the programme. Lessons for future programming include (i) matching of prescribed activity to body build, (ii) gentle progression (to avoid discouragement of the obese), (iii) attention to the desired rewards of the individual, and (iv) flexibility of class schedules to accommodate subjects with real or perceived time conflicts.

Anxiety↗