Number 26, 2005
Cardiovascular effects of exercise

Constructing an exercise program

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Andrew A. McLeod
Poole Hospital NHS Trust, Poole, Dorset, UK
Correspondence: Dr Andrew A. McLeod, Poole Hospital NHS Trust, Longfleet Road, Poole, Dorset BH15 2JB, UK. E-mail: andrew.mcleod@poole.nhs.uk

Better to hunt in fields, for health unbought
Than fee the doctor for a nauseous draught,
The wise, for cure, on exercise depend;
God never made his work, for man to mend.
John Dryden

Introduction
The Exercise Program has become an accepted part of almost every cardiac rehabilitation program. Few can accept such ex cathedra statements as Dryden's without some qualification, however. The data on which exercise programs are predicated seem secure, but myriad exercise programs abound, with doubtful efficacy for some. It seems best first to define what targets are to be achieved, and then to construct the program. A number of factors need to be considered.

The client group
Is the aim primary or secondary prevention of coronary heart disease? Special groups of patients to be considered include: women, those with diabetes, the obese, patients with heart failure and post cardiac transplant, patients with peripheral arterial disease, those with pulmonary disease, and individuals at very high risk, such as those with implantable defibrillators.

The personnel available
Few program developers will be able to design their ideal syllabus, and then recruit the personnel. The Lifestyle Heart Trial, for example, is unique in cardiac literature in crediting six chefs in a trial that only recruited 48 patients [1].

The likely level of funding
Appropriate monitoring for high-risk patients such as those with heart failure will increase costs.

The compliance factor
A minority of those invited to join traditional exercise programs actually participate. Is the aim to target those without the psychological or financial support, or who will find it difficult to travel to the exercise facility?

The age of the proposed clients
In the elderly, for example, rigorous aerobic training may not be appropriate (although some will participate). Programs that concentrate on strength training (to avoid muscle weakness and increased susceptibility to falls and injury) and flexibility training (to avoid disability and immobility) may achieve greater health gains overall, although remarkable benefits can be seen in the very elderly [2].

The location of the program
The standard gym or exercise facility program tends to attract a particular type of cardiac patient, usually male, and often at low cardiac risk. Home-based programs offer a better option for many, with equivalent results [3].

The wish to exercise
This differs subtly from compliance. The problem here lies in a client group that has never seen the value of exercise (particularly older women), and the difficulty is in achieving the change in behavior required to commence the exercise program. The initial aim should be to allow the patient greater personal control and responsibility, often by working in groups. The emphasis should be on non didactic teaching (a paradoxical term), together with support. ‘Knowledge is necessary but not sufficient to lead to changes in behavior’ [4].

Should exercise be on the ‘menu’?
This is related to the previous point. The benefits of exercise in almost all cardiac conditions (or associated conditions such as diabetes and obesity) are indisputable. There will be a group of patients however, who will not wish to increase their exercise level, but who may willingly accept the health benefits of other treatments. These include secondary drug prevention (eg, statins, ß-blockers, angiotensin-converting enzyme inhibitors), but might also include support for smoking cessation, and dietary modification. Not all clients will wish to take up all the potentially beneficial modifications on offer. Hence the concept of the rehabilitation ‘menu’. With this approach, the therapist tailors the treatments, advice, or support on offer to the perceived requirements of the client. Because this is a two-way process, however, the client should explore with the therapist which treatment on the menu is suitable for them.

What is already available?
There is no shame in copying a successful program. Therapeutic plagiarism is beneficial for all.

Exercise equipment
A recent meta-analysis of cardiac rehabilitation trials that included exercise, undertaken by Joliffe and colleagues for the Cochrane Collaboration [5], has indicated that exercise was the key component in cardiac rehabilitation programs that were associated with reduction in mortality. Not all programs achieve a substantial training effect. In the recent study by Hambrecht and colleagues [6], a vigorous aerobic exercise program conducted on stationary bicycle ergometers was as effective as intervention by percutaneous coronary intervention over a 1-year period, but this required exercise daily. The bicycle offers definite benefit in aerobic programs: the risk of injury is low; heart rate monitoring or respiratory impedance monitoring can accurately quantitate the level of exercise; the external work done can be quantitated accurately. Many patients, however, do not possess the innate quadriceps femoris muscle strength necessary to generate sufficient exercise muscle mass, which results in a substantial increase in oxygen uptake and heart rate. Such patients often find it easier to use a treadmill, which effectively limits them to a fitness center facility. Walking on the flat may not achieve required aerobic levels, however, and individuals in fitness centers are commonly seen exercising on horizontal treadmills. Gravity is a powerful and an extremely useful force in designing an exercise regimen, and even modest slopes considerably enhance oxygen uptake. Home equipment commonly makes use of gravity: for example, stepping up and down one or two stairs; lifting household items to improve upper body strength. In very elderly individuals, however, the ability to walk briskly may be compromised by unsteadiness. In the massively obese, even walking may risk orthopedic injury; for this group, exercise in a swimming pool, with the buoyancy effect of water to minimize injury, can be beneficial.

Assessment of exercise level
Outcome measures of exercise programs should be defined. Some relatively simple techniques have been described (6-min walk test [7], shuttle walk test [8]). Detailed cardiorespiratory gas-exchange techniques are cumbersome and usually only suited to research programs. If treadmill testing or ergometer testing is used, care should be taken to avoid familiarization bias. Heart rates recorded at the same submaximal workload as before the exercise program are valuable. For determining exercise prescription, the Karvonen [9] method for calculating desired levels of exercise during training is simple and accurate, and has also been validated for patients taking ß-blockers. Many programs use the self-estimated ‘rating of perceived exertion’ conceived by Gunnar Borg's group [10].

Exercise sessions
Some degree of compromise is necessary to set the level of participation required. There is no substitute for an enthusiastic and charismatic leader of a program. Exercise targets should be demanding, but not impossible to achieve. Patients easily lose motivation. Chair-based therapy, which has been used in both arthritis and cardiac patients, can be fun, requires minimal equipment, and is suited to the older or overweight individual. Compliance and adherence can be achieved through the camaraderie of the group, which provides a social as well as a therapeutic function.
If no funding of any consequence is available, very simple forms of exercise can be used. Simply meeting together and walking can be valuable, and is often organized by patient support groups. In the UK, this does not carry the same risk of litigation as in the USA, although this aspect needs to be considered. It may be adequate to have some form of diploma, which can be medically approved or countersigned, to allow simple exercise activity. Freedom from severe ischemia, or demonstrated arrhythmias, and treatment with appropriate drugs may be all that is required.

Conclusion
Exercise programs can range from the very sophisticated to the very simple. Although much publicity obtains for interventional treatments for coronary artery disease, every intervention is as much a failure, and an acknowledgment of failure, of preventive medicine as it is a success. Comprehensive care of the cardiac patient should integrate primary and secondary prevention of heart disease, in addition to intervention. ?

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REFERENCES

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