Progression of aerobic exercise intensity in a cardiac rehabilitation program

Introduction and ObjectivesTo describe the progression of aerobic exercise intensity in patients on a cardiac rehabilitation (CR) program.MethodsWe conducted a retrospective analysis of a random sample of patients referred for CR after acute coronary syndrome between 2008 and 2016. The weekly peak exercise intensity achieved during aerobic exercise was estimated by treadmill speed and grade at peak effort and the corresponding perception of effort was assessed using the Borg scale. Initial exercise intensity was prescribed as 60-80% of reserve heart rate plus resting heart rate, and was modified according to perceived exertion. Peak heart rate/intensity and perceived exertion index were used as variables to characterize the response to the intensity achieved. Variables were compared at different time points: T1 (1st week), T2 (4th week) and T3 (8th week).ResultsOf the total of 868, 238 patients were randomly selected. At peak heart rate during the session, exercise intensity (in metabolic equivalents) was: T1: 7.2±2.0, T2: 9.0±2.2, and T3: 9.4±2.2 (p<0.01). The peak heart rate/intensity index was T1: 16.8±5.4, T2: 13.4±3.6 and T3: 13.1±3.8 (p<0.01) and the perceived exertion index was T1: 1.8±0.6; T2: 1.4±0.5; T3: 1.4±0.5 (p<0.01).ConclusionsIncreasing exercise intensity during CR, associated with lower perception of effort and lower heart rate necessary to achieve such intensity, leads to significant improvement in functional capacity.     

Facemasks during aerobic exercise: Implications for cardiac rehabilitation programs during the Covid-19 pandemic

Introduction and objectivesDuring the COVID-19 pandemic, among the safety measures adopted, use of facemasks during exercise training sessions in cardiac rehabilitation programs raised concerns regarding possible detrimental effects on exercise capacity. Our study examined the cardiorespiratory impact of wearing two types of the most common facemasks during treadmill aerobic training.MethodsTwelve healthy health professionals completed three trials of a symptom-limited Bruce treadmill protocol: Without a mask, with a surgical mask and with a respirator. Perceived exertion and dyspnea were evaluated with the Borg Scale of Perceived Exertion and the Borg Dyspnea Scale, respectively. Blood pressure, heart rate and arterial oxygen saturation (SpO2) were measured at each 3-minute stage.ResultsUsing a surgical mask or a respirator resulted in a shorter duration of exercise testing. At peak capacity, using a respirator resulted in higher levels of dyspnea and perceived exertion compared to not wearing a facemask. A significant drop in SpO2 was present at the end of exercise testing only when using a respirator. There were no differences in either chronotropic or blood pressure responses between testing conditions.ConclusionsProfessionals involved in cardiac rehabilitation should be aware of the cardiorespiratory impact of facemasks. Future studies should assess whether exposure to these conditions may impact on the overall results of contemporary cardiac rehabilitation programs.     

High intensity exercise training programme following cardiac transplant

A 26-year-old male patient who presented with symptoms of end stage cardiac failure as a result of dilated cardiomyopathy, had an orthotopic cardiac transplantation. A comprehensive cardiac rehabilitation programme was provided to him and he was introduced to a sport (tennis). The exercise training programme progressed from low intensity training to high intensity programme over a period of 15 months. A cardio-pulmonary exercise test done 22 months after surgery suggested that he was able to achieve the aerobic capacity comparable to that of a normal South Indian subject. He participated successfully in the World Transplant Games in Sydney and returned safely. This suggests that after a proper cardiac rehabilitation programme, patients undergoing heart transplantation can achieve normal physiological responses to lead a normal active life.     

Developing the model of pulmonary rehabilitation for chronic heart failure

Patients with chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF) commonly suffer from exertional symptoms of breathlessness and fatigue. The similar systemic manifestations of the conditions, including skeletal muscle dysfunction, are a major contributing factor to the limitation in exercise capacity. A period of exercise training has been shown to improve exercise performance and health-related quality of life for both conditions. Exercise training is a key component of pulmonary rehabilitation (PR) which is now a standard of care for patients with COPD and is symptom based. Although it may be assumed that patients with CHF could be incorporated into cardiac rehabilitation, this is predominantly a secondary prevention programme for patients who are largely asymptomatic. It has been shown that patients with CHF can be successfully trained together with patients with COPD by the same therapists within PR. There are comparable outcome measures that can be used for both COPD and CHF. Many patients with CHF still do not have access to an exercise rehabilitation programme and incorporating them into the PR model of care could be one solution. This article reviews the (1) similar symptoms, mechanisms and consequences between COPD and CHF, (2) rationale and evidence for exercise training in CHF, (3) model of PR, (4) safety of exercise training in CHF, (5) evidence for combined exercise rehabilitation for CHF and COPD, (6) adaptations necessary to include patients with CHF into PR, (7) the chronic care model and (8) summary.     

Monitoring and rehabilitation of heterotopic cardiac transplantation patients during the period of convalescence

Heterotopic cardiac transplantation is a procedure performed in patients with severe pulmonary hypertension. Surgery is usually preceded by a long period of inactivity. This paper reports the results of a programme of cardiac readaptation, the complications observed, the improvement obtained and the problem replated to the absence of graft innervation. Eight patients who underwent heterotopic cardiac transplantation underwent the readaptation programme. This began with an exercise ECG on which the physical training programme was based. Sessions of respiratory and muscular physiotherapy were also arranged during the same period; a second exercise ECG was performed at the end of the programme to assess progress. Clinical, biological, electrocardiographic and echocardiographic parameters were carefully monitored. The results of the final exercise ECG showed the average maximal work capacity to be 90 watts for 3 minutes. The average increase in heart rate on effort was 25.92%. This was significantly higher than the resting heart rate (p less than 0.01). Two complications were observed during the programme: ventricular fibrillation of the cardiac graft and graft rejection on the 35th postoperative day, diagnosed by echocardiography. Progression of exercise capacity was observed in all patients. The two patients who made the least progress were those who underwent the fewest sessions of physical readaptation. This improvement was mainly related to peripheral muscular fitness. The training programme was well tolerated by all patients; the principal factor limiting an increase in cardiac output on effort was the absence of graft innervation. The heart rate can only be increased by two mechanisms: an increased venous return and raised concentrations of circulating catecholamines.(ABSTRACT TRUNCATED AT 250 WORDS)     

Utilization of heart rate at the ventilatory threshold for the prescription of intensity of exercise training in cardiac failure

Physical exercise is a treatment for cardiac failure but a large range of intensities of exercise is proposed. The aims of this study were to determine the range of intensities of effort used and to individualize the intensities used. Thirty patients with stable cardiac failure (NYHA Classes II-III, age: 53 +/- 2.1 years, ejection fraction: 31 +/- 1.4%) underwent a cardiorespiratory exercise stress test before and after individualized training at the ventilatory threshold. However, before and after the training period, standard methods of calculation of the intensities at the ventilatory threshold showed individual differences greater than +/- 2 standard deviations, indicating different metabolic stimulations. After the individualized training programme, peak oxygen consumption on exercise (1679 +/- 100 vs 1487 +/- 89 ml.min-1, p = 0.0001) and at ventilatory threshold increased (1365 +/- 85 vs 1133 +/- 65 ml.min-1, p = 0.0001), the ventilatory threshold/peak exercise ratio increased (81.2 +/- 1.3 vs 76.7 +/- 1.4%, p = 0.0008), and there was a decrease in heart and ventilatory rates at submaximal metabolic levels (p = 0.0001). The authors conclude that protocols using intensity of effort at the ventilatory threshold give similar results with respect to improvement of aerobic capacity as other methods of indirect calculation, based on maximal heart rate of oxygen consumption. The value of this particular method lies in the adequation between aerobic capacity of the patient and the intensity of training. The results obtained attain the physiopathological aims of rehabilitation.     

Defining the level of physical activity for a diabetic who is obese

Physical activity plays an important role in the treatment of metabolic syndrome and/or type 2 diabetes or obesity. Less than 20% of the adult population does physical exercise at least twice a week. The effectiveness of physical exercise depends on paying attention to the following parameters: the frequency, the intensity and the duration. The most difficult parameter to set for patients with obesity or metabolic syndrome is the optimum intensity of exercise. The most common means of measuring the intensity of physical activity is heart rate or pulse rate. With patients who take medicines that affect their heart rate, the Borg scale is used to give a subjective rating of perceived exertion. To set optimal intensity it is necessary to use exertion tests with these patients. The most accurate setting is a suitable combination of spiroergometry and a CHR (clamped heart rate) test. In practice, though, it is usually enough to combine ergometry together with the Borg scale. Tracking exertion parameters during exercise improves patient compliance and also the results of exercise.     

C-reactive protein and ST-segment monitoring by continuous 12-lead electrocardiogram in patients with primary unstable angina pectoris

The effect of exercise training on the heart rate recovery (HRR) response to submaximal effort was examined in 81 patients during 12 weeks of phase II cardiac rehabilitation. Although HRR after submaximal effort was relatively reduced in older patients with heart disease and in women, its increase during exercise training in men and women of all ages was consistent with enhancement of parasympathetic tone during activities of daily living.     

Pulmonary rehabilitation: an integral part of the long-term management of COPD

Pulmonary rehabilitation comprises a variety of interventions grouped into three main categories: exercise training, education, and psychological support. Typically, patients participate in a programme of exercise rehabilitation 2-3 times a week for 6-12 weeks, at the same time being encouraged to incorporate breathing and stretching exercises as part of their daily routine. The physiological rationale for pulmonary rehabilitation in COPD is primarily based on its effect on peripheral muscle dysfunction. A recent meta-analysis demonstrated that pulmonary rehabilitation is effective in reducing dyspnoea and fatigue as well as improving patients' sense of control (mastery) over their condition. Without compliance with a maintenance programme these improvements will diminish with time. The value of various components of rehabilitation, programme length, the required degree of supervision, the intensity of training and the best approach to maintaining programme adherence represent issues that remain to be explored.     

The physical fitness of elderly Nepalese farmers residing in rugged mountain and flat terrain

This paper reports the results of a natural experimental test of the hypothesis that elderly residents of rugged terrains are more physically fit than their counterparts in flat terrains due to the additional lifelong daily exertion occasioned by the inescapable need to walk up and down steep slopes. Cycle ergometer tests of physiological response to work were undertaken by two groups of high caste Hindu male farmers, aged 50 to 79, living in Central Nepal. One comprised an experimental group resident in rugged terrain and the other a control group resident in flat terrain. No differences in heart rate and blood pressure measured at submaximal workloads, at peak effort, or during recovery from exercise were demonstrated. Measurements of physical exertion revealed that few people in either terrain engaged in activity sufficiently strenuous to raise heart rates to a level where training could occur. Despite a rural agricultural lifestyle, these men were not especially physically fit.     

Beta-blockers do not impair the cardiovascular benefits of endurance training in hypertensives

Aerobic physical exercise is broadly recommended as a helpful adjunct to obtain blood pressure control in hypertension. Beta-blockade interacts with heart rate, sympathetic tone, maximal workload and local lactate production. In the present randomized-controlled study, we compared the cardiovascular effects of an endurance training programme in elderly hypertensives with or without beta-blockers and developed a first approach to determine a lactate-based training heart rate in presence of beta-blockade. Fifty-two patients (23 with beta-blocker, 29 without beta-blocker) > or =60 years with systolic 24-h ambulatory blood pressure (ABP) > or =140 mm Hg and/or antihypertensive treatment were randomly assigned to sedentary activity or a heart-rate controlled 12-week treadmill exercise programme (lactate 2.0 mmol/l). In the exercise group, the training significantly decreased systolic and diastolic 24-h ABP, blood pressure on exertion (100 W) and increased endothelium-dependent vasodilation (flow-mediated vasodilation, FMD) and physical performance both in the presence and absence of beta-blockade (P<0.05 each). The extent of ABP reduction did not significantly differ in the presence or absence of beta-blockade (Delta systolic ABP 10.6+/-10.5 vs 10.6+/-8.8 mm Hg, Delta diastolic ABP 5.7+/-8.6 vs 5.8+/-4.0 mm Hg). Mean training heart rate was significantly lower in the patients on beta-blockers (97.2+/-7.7 vs 118.3+/-7.5/min, P<0.001). Lactate-based aerobic endurance training evokes comparable cardiovascular benefits in the presence and absence of beta-blockade including a marked improvement of endothelial function. In the present study, target training heart rate with beta-blockers is about 18% lower than without.     

Possibilities of training for marathon races after myocardial infarction

The arguments against participation in marathon races after myocardial infarction are critically discussed. It can be demonstrated that most patients undergoing post-infarction rehabilitation have the physiological characteristics required to complete the necessary training. However, psychological and social considerations reduce the potential candidates to 33-50% of a typical sample, and only 1 or 2% of these would accept the demands of such an intensive training. So far, we are encouraged by the safety of marathon races for patients who are well trained and closely monitored. In addition, the influence of the training programme on smoking, serum lipid levels and heart work seems to be impressive. Participants are much less depressed, and a growing enthusiasm can be perceived in those of their colleagues who have a lesser reserve of cardiac function.     

New strategies to improve exercise tolerance in chronic obstructive pulmonary disease.

Breathlessness is the most common symptom limiting exercise in patients with chronic obstructive pulmonary disease (COPD). Exercise training can improve both exercise tolerance and health status in these patients, intensity being of key importance. Nevertheless, in these patients extreme breathlessness and/or peripheral muscle fatigue may prevent patients from higher levels of intensity. In this review article the literature concerning the different ways to optimise exercise tolerance in patients with COPD, with the objective of enhancing the tolerance to higher exercise training intensity, is summarised. Continuous positive airway pressure and different modalities of noninvasive positive pressure ventilation (NPPV) may reduce breathlessness and increase exercise tolerance in these patients. Respiratory muscle unloading and reduction in intrinsic positive end-expiratory pressure have been considered among mechanisms underlying these effects. Nevertheless, the role of NPPV in pulmonary rehabilitation, if any, is still controversial. The addition of nocturnal domiciliary NPPV during a daily exercise programme in patients with severe COPD resulted in an improvement in exercise tolerance and quality of life. In patients with severe COPD application of electrical stimulation combined with active limb mobilisation significantly improved muscle strength, and interval training has been shown capable of inducing physiological training effects. Oxygen supplementation in patients who do not desaturate during exercise seems to be the most promising treatment, since it allows for higher exercise intensities and, therefore, superior training efficacy. In conclusion, further studies are needed to define the appropriate patients in order to generalise such interventions. The modalities discussed should be used as adjuncts to a well designed comprehensive respiratory rehabilitation programme.     

Validity and reliability of the North Carolina 6-minute cycle test

PURPOSE: The purposes of this investigation were to determine (1) if the 6-minute cycle (6MC) test is a valid and reliable measure of physical performance in cardiac patients and (2) if physiologic responses to the 6-minute walk (6MW) and 6MC tests differ in men and women. METHODS: Subjects were 101 phase II cardiac rehabilitation patients aged 40 to 79 years. Each subject performed a maximal graded exercise test (MGXT), a 6MW test, and three 6MC tests on separate days. RESULTS: Pearson product moment correlation r values ranged from 0.78 to 0.89 (P = .001) when the three 6MC tests were compared with one another, indicating good test/retest reliability. The 6MC tests were all significantly and positively correlated to 6MW distance (P < .01), with r values ranging from 0.55 to 0.59. Each 6MC test was also correlated with maximal graded exercise test total time (P < .01), with r values ranging from 0.51 to 0.63, and with estimated maximal metabolic equivalents (P < .01), with r values ranging from 0.44 to 0.60. Although heart rate, systolic blood pressure, rate-pressure product, and rating of perceived exertion values for men were greater during the 6MC test than during the 6MW test (P < .001), no differences were seen in these parameters between tests in women (P = .166 to.260), with the exception of a greater exercise rating of perceived exertion seen during the 6MC test(P = .009). CONCLUSION: The North Carolina 6MC test seems to provide a valid and reliable measure of functional abilities in phase II cardiac rehabilitation participants. Men generally present with greater heart rate, systolic blood pressure, and rate-pressure product values during this test than do the women when compared with a standard 6MW test.     

Exercise Training in Patients with Chronic Heart Failure

Historically, patients with heart failure were advised to avoid exertion due to fear that the added myocardial stress would worsen heart function. However, between 1979 and 1991, five uncontrolled trials demonstrated that moderate exercise training can partially reverse the exercise intolerance common among patients with heart failure. Since 1991, numerous randomized exercise trials demonstrated a 12% to 33% improvement in exercise capacity, as measured by oxygen consumption. The mechanisms by which this improvement occurs are now being studied. Potential mechanisms include improved cardiac output due to increases in both peak stroke volume and reversal of chronotropic incompetence; improved regional blood flow to the metabolically more active skeletal muscle; and partial reversal of skeletal muscle histochemical abnormalities such as increased oxidative enzymes and a re-shift in fiber type toward increased type I fibers. Improved sympathetic function has also been noted with exercise training, evidenced by decreased norepinephrine spillover and increased heart rate variability. Exercise training can be of benefit in selected patients with stable New York Heart Association class II or III heart failure.     

Effectiveness of exercise training in patients with COPD: the role of muscle fatigue

The improvement in exercise performance in response to exercise training varies greatly from one patient with chronic obstructive pulmonary disease to another. It is possible that in a portion of patients the muscle stimulus applied during exercise training is insufficient to elicit training effects. We investigated whether patients presenting quadriceps contractile fatigue after training have more favourable effects of a rehabilitation programme. 46 patients followed a 3-month high-intensity exercise training programme. Exercise capacity, quadriceps force and quality of life were measured before and after the programme. Exercise training-induced quadriceps contractile fatigue was assessed after 1 month of rehabilitation with magnetic stimulation. A fall in quadriceps force of ≥15%, 15 min after training was considered as significant fatigue. 29 (63%) out of 46 patients developed significant fatigue. Patients with fatigue had a higher increase in 6-min walk distance (median (interquartile range) 57 (47-103) m versus 17 (-7-46) m; p=0.0023) and Chronic Respiratory Disease Questionnaire score (mean±sd 22±12 points versus 14±12 points; p=0.028) after the training programme compared with patients without fatigue. Improvements in quadriceps force and maximal exercise capacity were similar in both subgroups. Patients who develop quadriceps contractile fatigue during exercise training show greater training effects in terms of functional exercise capacity and health-related quality of life.