Reliability of a test of cardiovascular fitness

The reliability of a simple, cheap and portable test for estimating cardio-respiratory fitness (the Canadian Home Fitness Test) was assessed by the test/retest method. Substantial intra-subject variation was demonstrated which was between 49% and 85% of the observed group variation. At the 95% confidence level, this intra-subject variation represented an error of between 19.2% and 25.9% on the key measurement (mean post-exercise heart rate) depending on the degree of work done. The probable reason for this poor repeatability was observer error and this is discussed. It is concluded that this test is not suitable for either clinical or population research and alternative methods, such as historical review of physical activity, may be more useful.