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Biomedical subjects

R J Shephard

Publications and source records attributed to R J Shephard.

At least 307 records · Page 17Linked to original sources
PubMed1982

Step test predictions of maximum oxygen uptake before and after an employee fitness programme.

The Canadian Home Fitness Test has been administered to two large office populations on three occasions over a 9 month period. At the control company (87M, 89F), there was some improvement of test scores from the initial to the final visit (decrease of heart rate in 6th minute of exercise 5.7 beats X min-1 in men, 9.5 beats X min-1 in women); this may reflect habituation to the test procedure. At the experimental company (180M, 258F), employees were given the opportunity of participation in an Employee Fitness Programme. High adherents to this programme (61M, 97F) showed a substantial decrease of 6 min exercise heart rate (12.8, 16.0 beats X min-1) with an increase of CHFT duration (2.59, 2.33 min) and VO2max (Jetté prediction, 3.8, 2.9 ml X kg-1 min-1). These changes were much larger than in either the control group, or in "non-participants" (54M, 46F) and "drop-outs" (19M, 48F) in the experimental company. Low adherents to the fitness programme (46M, 67F) occupied an intermediate position. Given accurate pulse counting, about a sixth of the high adherents would have detected no change of CHFT score if a single test was carried out after completing 6 months in the fitness programme; however, in some of these subjects there may indeed have been no training response. Because it gives a low weighting to exercise heart rate, the Jetté equation indicates a smaller effect of training than the Astrand nomogram.

Adult↗
PubMed1982

Training and the respiratory system--therapy for asthma and other obstructive lung diseases?

The possible value of increased physical activity in prophylaxis and therapy is examined with specific reference to asthma and chronic obstructive lung disease. In asthma, the immediate response to exercise is a provocation of bronchospasm, but nevertheless affected individuals can reach the highest levels of competition. The main long-term value of training is probably an enhancement of self-image, consequent upon a normalisation of physical fitness and habitual activity; nevertheless, this can be therapeutic, particularly where asthmatic attacks are of psychogenic origin. In chronic obstructive lung disease, the main benefit of training is probably a breaking of the vicious circle of dyspnoea and decreased physical activity. Subjective gains are often remarkable, but immediate changes of pulmonary function are slight. More study is needed to determine the influence of such increased activity upon the long-term prognosis of chronic obstructive lung disease.

Adolescent↗
PubMed1981

Cardiorespiratory fitness and muscular strength of wheelchair users.

The classification of lower-limb disabilities is commonly based on the site of the spinal cord lesion or the amount of functional muscle. Another important variable in assessing wheelchair users is their ability to carry out the activities of daily living. The cardiorespiratory fitness of those with lower-limb disabilities is usually assessed with arm-ergometry and wheelchair tests, each of which has some advantages. Muscle strength and endurance are also important aspects of the disabled person's ability to function. Fitness is often poor in the disabled, and normal wheelchair use does not seem to prove an adequate training stimulus. Exercise with an arm ergometer and with pulleys and participation in vigorous wheelchair sports can improve physical condition. Participation in exercise programs should be based on the results of a fitness assessment and on the level of the spinal cord lesion in those with paraplegia. Progression in such programs should be gradual to ensure that the exerciser does not become discouraged and drop out of classes before fitness is increased. Data on wheelchair athletes suggest that, with persistence, many individuals in wheelchairs can adjust relatively well to their disabilities.

Arm↗
PubMed1981

Present views on the Canadian Home Fitness Test.

The Canadian Home Fitness Test was conceived for the mass testing of fitness levels and as a motivational tool in exercise programs. A double step (such as in a domestic staircase) is climbed at an age- and sex-specific rhythm set by a long-playing record. Fitness is assessed from test duration and the radial or carotid pulse count immediately following exercise. To date, use of the procedure by almost 500,000 Canadians has given rise to no serious complications. The test inevitably has limited precision when taken at home, although most subjects can learn to count their pulse and to step in time with the music. The test has been well received and has achieved its prime objective of stimulating an interest in endurance activity. When supervised by a paramedical worker using an electrocardiograph to monitor the heart rate during exercise, the procedure yields as good an estimate of maximum oxygen intake as other submaximal tests. One current area of controversy is the interpretation of abnormal electrocardiograms. It is suggested that this problem could be resolved by the appropriate training and certification of interested family physicians and paramedical workers.

Allied Health Personnel↗
PubMed1981

Oronasal distribution of respiratory airflow.

The oronasal distribution of respiratory airflow was determined during incrementally graded submaximal exercise 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 two airflow signals were sampled every 20 msec by a microprocessor, which calculated the oral and nasal minute volumes (separating inspiration and expiration) and produced an on-line print-out of the results. Twenty subjects ("normal augmenters") switched from nasal to oronasal breathing at a VE of 35.3 +/- 10.8 1 . min-1, four subjects ("mouth breathers") habitually breathed oronasally, five subjects ("nose breathers") persistently breathed through the nose only, and one subject showed no consistent nose/mouth breathing pattern. After the switch to oronasal breathing, the nasal portion of VE decreased suddenly to 57% of total VE. With a further increase of VE, oral minute volume increased rapidly, equalling nasal minute volume at a VE of 45 1 . min-1, and accounting for 61% of the total ventilation at high respiratory minute volumes (90 1 . min-1). During oronasal breathing, normal augmenters inspired some 2 1 . min-1 more nasally than they expired. Similarly, the nasal inspiration of mouth breathers exceeded expiration by 2 1 . min-1 at rest, but the difference increased to 13.51 . min-1 at a VE of 81.51 . min-1.

Adolescent↗
PubMed1981

Controlled exercise elevates plasma but not urinary MHPG and VMA.

The effect of controlled exercise on plasma and urinary 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) and vanillylmandelic acid (VMA) was investigated in normal subjects. After 3 days of bed rest, six normal volunteers engaged in controlled exercise adjusted to a constant 40% of the individual's maximum oxygen intake. The exercise program consisted of 4 miles of walking and a half-hour each of bicycle ergometry and treadmill walking. Both plasma VMA and MHPG were higher on the exercise day than on the resting day, while urinary VMA and MHPG levels did not differ from rest to exercise. The mean urinary MHPG/VMA ratio (0.46) differed markedly from the mean plasma MHPG/VMA ratio (2.3). Plasma and urinary MHPG apparently represent different indices of norepinephrine metabolism.

Adolescent↗
PubMed1981

Prognosis in myocardial infarction--the benefits of exercise as seen in non-randomised trials.

Previous uncontrolled studies suggest that exercise rehabilitation reduces recurrence rates in post-myocardial infarction patients. Six hundred and ten consecutive post-coronary patients referred to an exercise rehabilitation programme have been followed for an average of 36.5 months (1-8 years). Total deaths amounted to 36 (1.89% p.a.) of which 23 were cardiac deaths, with an annual death rate averaging only 0.85% after the first year of conditioning had been completed. There were also a total of 21 non-fatal recurrences of infarction. comparison has been made with 700 patients enrolled in the Health Insurance Plan of New York. On the basis of smoothed probabilities for the risk factors reported in the New York series, we should have seen 89 deaths (P less than 0.001). Correcting for differences between the two groups (age and number of diabetics) gives a predicted mortality for the Toronto series of 63.5 deaths (3.42% p.a.). This discrepancy in favour of the exercised group is significant in terms of an infinitely large control population (P less than 0.001) and also sample sizes of 610 exercised and 700 control patients (0.01 greater than P greater than 0.001). Unfortunately, formally to prove such a 45% reduction in mortality by way of a randomised control trial would be extremely costly, possibly prohibitively so.

Canada↗
PubMed1981

Use of isovolume flow curves in the detection of exercise-induced bronchospasm.

A simple 9-min progressive cycle ergometer test revealed exercise-induced bronchospasm in 23 of 29 asthmatic subjects (80%) in terms of a 15% decrement in the isovolume forced expiratory flow rate at 50% of the baseline vital capacity (Vmax iso 50%VC). A similar percentage was detected by the Vmax iso 60% TLC (78%), but that found with the FVC (35%) and FEV1.0 (48%) was somewhat lower The maximum change of Vmax iso 50%VC following exercise in normal subjects was -5.2 +/- 2.1%. The Vmax iso 50%VC thus combines sensitivity with specificity, and seems a very suitable procedure for routine clinical use. Asthmatics showing a positive reaction to this test were distinguished by poor pre-exercise lung function.

Adult↗
PubMed1981

Exercise-induced bronchospasm - pathophysiology and treatment.

The practical importance, prevalence, typical features, physiopathology and therapy of exercise-induced bronchospasm (E.I.B.) are briefly reviewed. The condition is common, especially in children. Prevalence is influenced by the mode, intensity and duration of exercise, the age and possibly the sex of the subjects, the number of test repetitions, and the criterion for presence of spasm. The main site of obstruction is in the large airways. Symptoms appear a few minutes post-effort, peaking 10-15 minutes after exercise. At different times, spasm may arise in the vagal reflex arc, from alterations of sympathetic balance, prostaglandin release, and sensitization of the mast cell. Until recently, the main basis of prophylaxis has been inhalation of sodium cromoglycate (20 mg, 60 minutes prior to competition). Beta agonists have until recently been prohibited in international competitions. However, the use of selective beta agonists such as salbutamol and terbutaline was allowed in the 1978 World Swimming Championship and the 1980 World Cross-Country Championship with a supporting medical letter. The Medical Commission of the International Olympic Committee has also moved recently to sanction the use of salbutamol and terbutaline. Future prophylaxis will thus be based on combinations of selective beta agonists and sodium cromoglycate.

Adult↗