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Biomedical subjects

R J Shephard

Publications and source records attributed to R J Shephard.

At least 397 records · Page 22Linked to original sources
PubMed1977

Exercise-induced bronchospasm-a review.

The nature, causes and treatment of exercise-induced bronchospasm (E.I.B.) are reviewed. The condition is common, particularly in children. The spasm affects mainly the large airways; it appears a few minutes after effort, peaks in 10-15 minutes, and commonly resolves spontaneously in 40-60 minutes. The origin is probably multifactorial, with reflex stimulation of tracheal receptors, altered sympathetic neural discharge, prostaglandins and mast-cell sensitization being involved on different occasions. Effective treatments are equally varied, including selective beta agonists, theophylline and cromolyn glycate. For the sports physician, the best current approach seems the use of the Cromolyn drugs about one hour prior to competition.

Acidosis, Respiratory↗
PubMed1976

Development of the Canadian Home Fitness Test.

The Canadian Home Fitness Test is a self-administered procedure in which the participant steps at an age- and sex-specific rhythm controlled by recorded music, then palpates the pulse immediately following activity. Validation of the test has shown a correlation of 0.72 with the results of a standard submaximum bicycle ergometer test, while the directly measured maximum oxygen intake is correlated even more closely (r = 0.88) with the attained stepping rate, body weight and recovery heart rate. Given modest training, subjects could measure their immediate postexercise heart rate (correlation with electro-cardiographic data, r = 0.94), although 10-second counts underestimated the true rate by an average of 7 beats/min. The safety of the test will be established ultimately by experience in its use in a large population; nevertheless, both theoretical considerations and results of trials in over 14 000 adults suggest the procedure can be self-administered without serious consequences. It is also well accepted by the general public and arouses considerable interest in most homes. The test can thus be recommended as providing an approximate measure of an individual's physical fitness in order to stimulate an increase in personal physical activity. It also has potential as a simple screening procedure that would allow paramedical personnel to record fitness levels and standardized exercise electrocardiograms in large segments of the population.

Adolescent↗
PubMed1976

Some reactions to a dry-land training programme for dinghy sailors.

A dry-land winter training programme for dinghy-sailors is described. Individual elements include circuit training, specific exercises for muscle strength and endurance, and distance running. Ten international-class sailors followed a progressive regimen of this type for 14 weeks after completion of the 1973 season. Excess weight and skinfold thicknesses were reduced, while muscle strength, endurance and anaerobic capacity increased. Aerobic power remained substantially unchanged, although a smaller oxygen debt was incurred in reaching maximum effort. Team members were enthusiastic about the benefits gained from the training, commenting on their greater tolerance of the hiking position and all proposed to continue or to increase their efforts during subsequent winters. Racing results during 1974 were also an improvement on the 1973 record. However, it was difficult to link physiological gains to improvements in the relative rankings of individual competitors under either light or high wind conditions; the main factor changing relative standings seems to have been the additional year of competitive experiences in younger team members.

Body Weight↗
PubMed1976

Maximum exercise tests on "postcoronary" patients.

The maximum oxygen intake has been measured directly (uphill treadmill walking) in 36 patients following recovery from myocardial infarction. These were selected as follows: 15 consecutive new entrants to an exercise program that is currently accepting about one-sixth of the total reported myocardial infarction hospital admissions in metropolitan Toronto (group A), 12 patients not responding well to training (group B), and 9 patients now running substantial distances (group C). The only clinical complications were two episodes of ventricular tachycardia. Twenty patients reached an oxygen plateau, and in group C, the maximum heart rate (170/min) reached Scandinavian norms, with a maximum oxygen intake (2.63 +/- 0.35 1/min STPD, 36.9 +/- 4.8 ml/kg-min STPD) as in healthy men of the same age. The rate of adaptation to a progressive submaximum test was such that comparable Astrand nomogram predictions of VO2max were obtained from data in the 3rd and 5th min at the third load. Predictions generally agreed closely with directly measured values. It may be concluded that in patients who have recovered sufficiently to enter an exercise rehabilitation program 1) predictions of VO2max have about the same accuracy (+/-10) as in healthy subjects, and 2) direct measurements can often be pursued to an "oxygen plateau" without due risk.

Adult↗
PubMed1976

Pulmonary function changes in ozone-interaction of concentration and ventilation.

A total of 28 healthy young subjects have been exposed for 2 h to ozone (0.37-0.75 ppm) under conditions of either rest or intermittent light exercise (sufficient to increase the respiratory minute volume by a factor of 2.5). All pulmonary function tests (vital capacity, forced expiratory volume, maximum expiratory flow-volume curve, slope of phase III of alveolar nitrogen plateau) showed a significant deterioration relative to parallel control experiments. Responses were related to the dose of ozone as calculated from the product of concentration, exposure time, and respiratory minute volume during exposure, changes at 1 h averaging approximately one-half those seen at 2 h.

Adult↗
PubMed1976

Attitudes towards health and physical activity in the elderly. Effects of a physical training program.

Attitudes towards physical activity, perceived health, body image, anxiety and life satisfaction have been studied in men and women 60 years of age and older, volunteering for progressive endurance training. Relative to other studies of younger volunteers, the senior citizens placed more value upon activity as "an esthetic experience" and as "a means to health and fitness" showing less interest in "the pursuit of vertigo." Many non-participants and "drop-outs" perceived their current fitness as satisfactory. Subjects who selected a low frequency and low intensity of training were obese, with high Cornell Medical Index (CMI) scores on both organic and psychological scales. After 14 weeks of conditioning, 83% of subjects reported improvements in well-being. However, CMI scores were reduced on only one of twelve organic scales and none of the behavior, mood and feeling scales. Neugarten's Life Satisfaction Index, Kenyon's Body Image scales, and McPherson's the Real Me scores remained unchanged, but there was a decrease of Manifest Anxiety (Taylor scale) and a greater regard of physical activity as "the relief of tension." When subjects were classed according to changes in aerobic power, between group differences were found for "Real Me" scores and for three of Kenyon's attitude scales. Persons who trained frequently and intensively showed improvements for body image and for five of Kenyon's attitude scales.

Aged↗
PubMed1976

Attitudes towards health and physical activity in the elderly. Effects of a physical training program.

Attitudes towards physical activity, perceived health, body image, anxiety and life satisfaction have been studied in men and women 60 years of age and older, volunteering for progressive endurance training. Relative to other studies of younger volunteers, the senior citizens placed more value upon activity as "an esthetic experience" and as "a means to health and fitness" showing less interest in "the pursuit of vertigo." Many non-participants and "drop-outs" perceived their current fitness as satisfactory. Subjects who selected a low frequency and low intensity of training were obese, with high Cornell Medical Index (CMI) scores on both organic and psychological scales. After 14 weeks of conditioning, 83% of subjects reported improvements in well-being. However, CMI scores were reduced on only one of twelve organic scales and none of the behavior, mood and feeling scales. Neugarten's Life Satisfaction Index, Kenyon's Body Image scales, and McPherson's the Real Me scores remained unchanged, but there was a decrease of Manifest Anxiety (Taylor scale) and a greater regard for physical activity as "the relief of tension." When subjects were classed according to changes in aerobic power, between group differences were found for "Real Me" scores and for three of Kenyon's attitude scales. Persons who trained frequently and intensively showed improvements for body image and for five of Kenyon's attitude scales.

Adult↗
PubMed1975

Depression after myocardial infarction.

The Minnesota Multiphasic Personality Inventory was completed by 101 patients 16 to 18 months after a proved myocardial infarction. The data suggested a bimodal distribution of patients. One class of patients had a relatively "normal" personality score apart from a tendency to hypomania. The second class had severe depression, with associated hysteria, hypochondriasis and psychasthenia. The severely depressed patients were older, with a greater tendency to hypertension and angina, and a tendency to smaller gains in aerobic power despite an equal intensity of endurance training. The distinction between "normal" and "depressed" postinfarction patients seems of some clinical importance, for the two classes of patients require opposite supportive techniques--restraint and encouragement, respectively.

Age Factors↗
PubMed1975

Carbon monoxide in the urban atmosphere: hazards to the pedestrian and the street-worker.

The carbon monoxide (CO) concentrations encountered by pedestrians and workers in the streets of a large metropolis were monitored by a reliable and sensitive portable detector (the Ecolyzer). Up to 1,000 observations per day were collected for several months during the summer and fall of 1973. The CO levels ranged from 10 to 50 ppm (varying with wind speed and direction, atmospheric stability, traffic density, and the height of nearby buildings). Much higher average concentrations were found in such adverse sites as poorly ventilated underpasses and underground garages. Street closures for a pedestrian mall reduced levels on the mall to around the general urban background withoug large increases in readings on adjoining streets. Many street-workers have little medical supervision, and for this reason the urban eight-hour CO ceilings may be a more appropriate air quality target than the usual industrial figure of 50 ppm. However, even the latter is sometimes exceeded on busy city streets.

Air Pollution↗
PubMed1975

A controlled prospective study of the effect of endurance training on the recurrence rate of myocardial infarction. A description of the experimental design.

A multicenter prospective study has been designed to determine whether participation in an exercise program which produces a significant training effect will affect the recurrence rate in men who have survived an initial myocardial infarction. The control group consists of subjects who participate in a program involving low intensity activities designed to avoid a significant training effect. The subjects will be followed for a period of 4 years and a reduction of 50 per cent in the risk of recurrence will be considered clinically significant. The criteria for entry, the method of allocation, the structure of the exercise program and method of assessing cardiorespiratory fitness are described.

Angina Pectoris↗
PubMed1975

Efficiency of muscular work: some clinical implications.

The concept of mechanical efficiency is briefly reviewed. Biochemical considerations set a maximum potential efficiency of 25 percent, but, in some instances, storage of energy in elastic tissue may yield a higher apparent efficiency. Comparisons of efficiency between normal and handicapped individuals can be made in terms of the oxygen cost of specific activities, or, if due regard is paid to the effects of the primary disease, the simpler indexes of pulse rate and ventilation may be used. Measurements of efficiency can be helpful in improving the working technique of both the healthy individual and the handicapped person, Useful gains of efficiency can result only if tasks initially have an efficiency substantially below the theoretical ultimate of 25 percent.

Adenosine Triphosphate↗
PubMed1975

Respiratory gas exchange ratio and prediction of aerobic power.

The Issekutz procedure for the prediction of maximum oxygen intake from the respiratory exchange ratio (R) has been evaluated on a diverse group of 308 subjects, including "whites" and Eskimos, men and women ranging in age from 16 to 65 yr. When applied to young white men performing 12 min of progressive step or treadmill exercise, the prediction procedure has a coefficient of variation of less than 10%, without systematic error. Unfortunately, the standard equation lacks generality, and erroneous predictions can arise from a change of test protocol, the use of a different exercise modality, or application to older subjects. If a brief exercise format is used, low R values may be reported during an early phase of relative hypoventilation. At a given metabolic loading, bicycle ergometry yields a higher respiratory minute volume than other modes of exercise. A heavy loading of one muscle group seems responsible, and the results is a high R value in submaximum effort. Aging is associated with a lowering of maximum blood lactate levels and thus maximum figures for R.

Adolescent↗
PubMed1975

Exercise responses following ozone exposure.

We have tested the response of 28 subjects to a three-stage ergometer test, with loads adjusted to 45, 60, and 75% of maximum aerobic power following ozone exposure. The subjects were exposed to one of 0.37, 0.50, or 0.75 ppm O3 for 2 h either at rest (R) or while exercising intermittently (IE) (15 min rest alternated with 15 min exercise at approximately 50 W. sufficient to increase VE by a factor of 2.5). Also, all subjects completed a mock exposure VE, respiratory frequency (fR), mixed expired PO2 and PCO2, and electrocardiogram were monitored continuously during the exercise test. Neither submaximal exercise oxygen consumption nor minute ventilation was significantly altered following any level of ozone exposure. The major response noted was an increase in respiratory frequency during exercise following ozone exposure. The increase in fR was closely correlated with the total dose of ozone (r = 0.98) and was accompanied by a decrease in tidal volume (r = 0.91) so that minute volume was unchanged. It is concluded that through its irritant properties, ozone modifies the normal ventilatory response to exercise, and that this effect is dose dependent.

Adult↗