Field tests in cardiac rehabilitation
Prof Vincent GREMEAUXa
a CHU Dijon
Assessment of physical capacity is a major concern , given the increasing prevalence of chronic disabling conditions due cardiovascular disease, usually associated with an intolerance to effort leading to reduced physical activity.
Maximal exercise tests remain the reference because they can rule out contra-indications to retraining, help in drug prescription optimization, measure the maximal capacity in terms of heart rate, maximum power or peak VO2. However, they require specific technical and human resources, and therefore imply a financial burden limiting which their repeatability in clinical practice. In addition, they may not be well tolerated in patients with severe cardiovascular impairement, multiple co-morbidities, and / or the older ones. Moreover they are not representative of the actual functional capabilities in ecological conditions. As a result, field tests, associated with a collection of physiological parameters, can represent an alternative to assess exercise intolerance in cardiac rehabilitation (CR).
The most used are walk tests, designed to evaluate the safety and exercise capacity in healthy subjects and patients from a speed or walking distance. These tests can be maximal (most often imposed with increasing speed), in order to get an idea of the prognosis (prediction of peak VO2) or submaximal at a constant speed or a self-selected comfortable speed (6-minute walk, for example). Submaximal tests are considered as valuable benchmarks for measuring the response to a standardized activity typically encountered in everyday life. This performance evaluation can be performed before and after an intervention (surgery, medication, rehabilitation) in order to assess its effects. It can also help to assess the quality of life and could be a tool to personnalize training programs.
Field tests have the advantage of being simple to perform, well tolerated, require few expertise and equipment, and appear well connected with daily activities. However, they have usually a modest correlation with peak VO2, and appear strongly influenced by familiarity and influence the motivation of the subject.
The aim of this update is to describe the main walk tests used in the cardiac rehabilitation, their psychometric properties and interests in clinical practice, performed in addition to or instead of maximal stress tests.
Keywords : cardiac rehabilitation, assessment, field tests, physical capacity