Scot Med J 1991;36: 038-041
0036-9330/91/06290/038 $2.00 in USA e 1991Scottish Medical Journal
THE EFFECTS OF EXERCISE IN A CORONARY REHABILITATION PROGRAMME M. Newton/ N. Mutrie,2 J. D. McArthu,-3 Iphysiotherapy Department, Gartnavel General Hospital, Glasgow. 2Department of Physical Education and Sports Science, University of Glasgow. 3Department of Cardiology, Western Infirmary, Glasgow.
Abstract: Twenty-two male and female patients who had recently suffered a myocardial infarction were randomly assigned to a treatment group who participated in a IO-week exercise-based cardiac rehabilitation programme or a routine care group who did not participate in the rehabilitation programme. Physiological and psychological function were assessed before the programme started and after it finished. Results indicated that the treatment group did not improve physiological functioning more than the control group but they did evidence statistically significant improved psychological functioning. This investigation appears to be the first attempt to assess the potential benefits of an exercise-based cardiac rehabilitation programme in Glasgow and supports the suggestion that exercise-based cardiac rehabilitation has psychological benefits. Key words: Cardiac rehabilitation, exercise, mood, depression.
Introduction COTI1SH death rates from coronary heart disease (CHD) are among the highest in the world, and unlike many countries have not been falling.' There are enormous costs in human and economic terms. Individuals suffer pain, disability, fear and bereavement, while the economy of the nation is weakened by sickness and absence from work, early retirement and demands on social services. 2 The prevention and rehabilitation of this disease is, therefore, of paramount importance in Scotland as a whole and Glasgow in particular; some districts in Glasgow have rates up to 20% above the Scottish average.? Prevention is now being tackled by the Greater Glasgow Health Board which launched 'Good Hearted Glasgow' in 1986. This campaign is a multiple risk factor cardiac disease prevention programme. However, rehabilitation has been neglected." After a heart attack has occurred rehabilitation is unlikely to be available in Glasgow. In 1988 the only rehabilitation programme running was at Gartnavel General Hospital. The rehabilitation programme at Gartnavel is based on exercise and is the subject of this report. The benefit of an exercise-based rehabilitation programme has not been extensively evaluated. Early epidemiol0.pcal research linked exercise to prevention of CHD. 5,6, Uncontrolled studies suggested that exercise was beneficial following onset of disease. 8 Randomised controlled studies,9,8 using mortality and morbidity as end points, have been inconclusive, although one study'" found that multifactorial programmes contributed significantly to reduction in the number of sudden deaths following coronary heart disease. Other controlled trials have suggested that exercise has physiological benefits; several studies show a significant rise in maximum V0 2 in patients after an exercise programme. 11,12,13 The need to evaluate psychological aspects of an exercise-based cardiac rehabilitation pro~amme has been recognised by several clinicians.14,1~,16, 7 They realised from anecdotal observations (eg - "morale was high in the exercise group"11) that, although exercise-based programmes had been offered initially because of potential beneficial effects on the cardiovascular system, they also appeared to have psychological benefits. 18 One interesting piece of research'< combined physio-
Address for correspondence and request for reprints: Dr N. Mutrie, Department of Physical Education and Sports Science, University of Glasgow, 77 Oakfield Avenue, Glasgow G12 8LT.
logical and psychological aspects. The result showed both parameters improved for the exercise group. Unfortunately, there was no true randomisation done as the control group was defined by geographical location from the hospital. The following investigation was carried out on the Gartnavel Hospital coronary rehabilitation programme. The aim of this study was to evaluate the potential benefits of an exercise-based rehabilitation programme. The design adds to the previous literature by focussing on psychological variables and by incorporating random assignment to groups. METHODS Subjects The subjects were male (n = 29) and female (n = 11) patients who had recently experienced a myocardial infarction and who met the criteria for participation in the cardiac rehabilitation programme. The programme selection criteria included: 1) Age 70 years or younger. 2) Myocardial infarction documented by clinical history, electrocardiograph and enzyme evidence. 3) Minimum of six weeks post-myocardial infarction. 4) No physical or cardiovascular problems which could preclude full participation in the exercise programme, eg arthritis of hips and/or knees. Method The subjects were identified while in hospital after the diagnosis was confirmed by a consultant cardiologist. They were randomly assigned to an exercise-based group or a routine care group. Twenty subjects were assigned to each group. From the exercise-based group, four failed to attend for first appointment; one broke his leg and three were withdrawn because of drug treatment. This left 12 in the treatment group. From the control group, four failed to attend the first appointment, two died before or after leaving hospital and four were withdrawn due to drug treatment. This left 10 in the control group. The subjects were all from the catchment area of Gartnavel General Hospital which serves the western end of the city of Glasgow. TREATMENT GROUPS
Routine care treatment group Routine care was given to both groups of patients. This consisted of a visit from the liaison nurse while the patient
Exen:ise-bued canIilIc rebabiHtatioo
Newton, Mutrie, McArthur
was still in hospital and again within two weeks of arriving home. Education about coronary heart disease was given by the liaison nurse. This was directed towards stopping smoking and modification of diet. The liaison nurse was available to relatives who wished to ask questions while the patient was still in hospital and also on arrival home. Exercise-based treatment group The exercise-based programme ran twice a week at Gartnavel General Hospital. The exercise was aerobic, usin~ large muscle groups and avoiding static arm exercise. 9 Exercise prescription for cardiac patients follows the guidelines used for the normal population.P' With myocardial infarction patients it is important to consider the initial level of fitness. Within the first 6-8 weeks caution should be used until scar tissue has formed in the myocardium. During the first 8-10 weeks progression is made with duration and frequency rather than with intensity." The maximum exercise heart rate reached on the exercise tolerance test was used as a guideline to work out training heart rate. By the tenth week patients would normally exercise three times a week. Two of these occasions were within the supervised hospital programme; the third was completed at home. Each session lasted approximately one hour. Within this hour heart rate remained within the training zone for at least 30 minutes. The training zones were calculated for each patient using the formula 60-80% of maximum heart rate achieved on the exercise tolerance test. The class started with a warm-up after which patients followed an individualised programme. Patients were taught to take their own heart rate before, during and after exercise and again after a short rest. In this way they monitored the intensity of exercise. One exercise session per week was followed by a short muscular relaxation session. The other session was followed by an informal talk on one of the following subjects: 1) risk factors in coronary heart disease 2) structure and function of the heart 3) benefits of exercise 4) role of diet in coronary heart disease 5) medication in coronary heart disease 6) stress in coronary heart disease Advice on stopping smoking and weight control were available at each class which was attended by two physiotherapists, the liaison nurse, and a senior house officer from the cardiology department. Patients had ample time to talk to each other after each session was over and appeared to derive great benefit from this. Spouses of subjects were encouraged to attend both the classes and the talks, as this allowed them to see the amount of exercise their spouses were capable of completing.
increase in workload between stages than other protocols; this may make it more sensitive to picking up ischaemic electrocardiograph responses than a slower incremental increase.P The test was symptom limited, the end point being determined by the patients' inability to continue for any reason, S-T segment depression or significant arrhythmia on electrocardiograph. The patient's resting heart rate was measured before the test. The two measures which were used as the physiological dependent measures were resting heart rate and time on the treadmill. Psychological function Two standard measures of current ps~hological distress, the Beck Depression Inventory (BDI) and the Profile of Mood States (pOMS)25 were administered to each subject. The subjects were asked to respond to both scales with reference to how they felt during the past week. The BDI is a self-report instrument which has 21 items. Each item is identified by a letter and relates to one of a set of symptoms which Beck24 has identified as a manifestation of depression. Studies'? of the instrument indicate a high degree of validity and reliability. The POMS scale was used because it was easy and quick to administer. It has been proved to be effective in other studies of exercise.P It has six separate mood scales: tension-anxiety, fatigue-inertia, depression-dejection, anger-hostility, vigour-activity and confusion-bewilderment. Comparison between the scores on the inventory and clinical jUd~ements of diagnosticians indicate a high degree of validity. Results The data were analysed using the SPSSX statistical package. A two (groups) by two (time) analysis of variance was made with repeated measures. The analysis for scores on BDI showed a significant interaction effect between groups and time (F (1,20) = 6.48, p< .02). The follow-up tests showed a significant (t (l I) = 2.59, p < .025) decrease in depression scores for the exercise-based group from pre-treatment levels (M = 8.8) to those after treatment (M = 5.0). The follow-up r-tests for the routine care group showed no significant change in depression scores pre-treatment levels (M = 7.3) to post-treatment (M = 8.1). This interaction is illustrated in Fig. 1. ---0--15
Exercise group A Routine care group B
(~= 12) (~= 10)
F ( 1, 20 ) = 6.48,'p • 0.02
DEPENDENT MEASURES All dependent measures were taken six weeks postmyocardial infarction and again 10 weeks later. Physiological function An exercise tolerance test was used to evaluate the severity of the disease, reveal unexpected responses to exertion and provide an appropriate base line by which the effects of rehabilitation could be assessed physiologically. 22 The test was supervised by the registrar in the department of cardiology and the electrocardiograph technician. The Bruce protocof" was used to assess cardiac function. This is a multistage exercise tolerance test with a more abrupt
Fig. 1. Mean scores on Beck Depression Inventory from pre-treatment to post-treatment.
A similar significant interaction was shown on the tension and depression sub-scales POMS with scores reflecting a significant decrease for the exercise group, but not for the
Newton, Mutrie, McArthur
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routine care group. This pattern was seen again in the anger sub-scales and in Total Mood Disturbance (Total Mood Disturbance is a summation of the six POMS sub-scales). However, these did not show a significant decrease for the exercise-based group. The analysis of the POMS vigour and confusion sub-scale showed no significant main effects or interactions. However, the analysis of the POMS fatigue sub-scale showed no interaction effect but did show a significant main effect over time, (F