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considered to be 3.5 ml(kg.min). The 70kg person who bums 1.2 kilocalories per miflute sitting at rest uses approximately 3 METs when walking 4 kilometers per hour
Table 2 displays the relationship of excess energy expenditures in METS to functional class according to the protocols of several investigators. With all the protocols, the exercise periods last for three minutes; the periods are represented in the table by boxes with numbers giving the estimated METs involved.If a treadmill is not available, steps may be used to attempt to quantitate the exercise capacity of a patient.
Table 3 shows the relationships of exercise with steps of various heights, excess energy expenditure, and functional class. Estimations of excess energy expenditure also can be made with a bicycle ergometer (Table 4).Some laboratories are equipped to measure oxygen consumption and carbon dioxide production during exercise.
Data on a patient acquired by these techniques may become the most accurate method of estimating a patient’s exercise capacity. A major problem with using any exercise-testing technique to attempt to quantitate an individual’s functional capacity is the marked variability in the patient’s abilities and willingness to cooperate. Therefore, the physician also must estimate the individual’s cooperation and effort during the test; some patients will continue far beyond where they should, while others will stop after minimal effort because they feel fatigued.
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