ATS Pulmonary Function Laboratory Manual

ATS Pulmonary Function Laboratory Management & Procedure Manual | 3rd Edition

2.1.1. A wide range of recommended heart rate levels are reported in the literature (5, 6, 15, 48, 63, 69). Achieving 85% (adults), and 90% (children ) of the predicted maximal heart rate for the patient is the most common approach. 2.1.2. Two simple equations have been described for predicting maximum heart rate (Max HR) (39, 40, 49): 1. Max HR = 210 − [0.65 × (age)] 2. Max HR = 220 − age. 2.1.3. Predicted Max HR can be affected by medication (e.g. beta-blockers) (37) 2.1.4. Multiply predicted Max HR times 0.85 to obtain target heart rate. 2.2. Minute ventilation ( ˙ V E) can also be monitored; however, this requires monitoring expired gas during exercise. Exercise intensities can be chosen to target 40 to 60% (80% in elite athletes) of the measured or calculated maximum voluntary ventilation (MVV) (36, 48). 2.2.1. Calculated MVV equals 35 to 40 times the measured FEV 1 (49). 2.2.2. Multiply MVV times 0.4 to 0.6, or 0.8 for elite athletes. 2.3. Using 60 to 80% of the predicted maximum O 2 consumption ( ˙ V o 2 max) has also been reported (19, 53, 69), but determination of O 2 uptake may be more complicated and impractical. 2.3.1. Calculate predicted ˙ V o 2 max ; one set of regression formulas (39) is: 1. Males: [60 − 0.55(age)] × (weight in kg) 2. Females: [48 − 0.37(age)] × (weight in kg) 2.3.2. Multiply predicted ˙ V o 2 max times 0.60 to 0.80 to obtain target ˙ V o 2 . 2.4. Treadmill protocols 2.4.1. Several standardized treadmill protocols state the work rate relationship at each stage to a corresponding MET (metabolic equivalent) (70–72). 2.4.2. To calculate the ˙ V o 2 for a target work rate: 1. Calculate the target ˙ V o 2 . 2. Divide target ˙ V o 2 by the patient’s body weight in kg. 3. Divide ˙ V o 2 /kg by 3.5 to obtain MET value. 4. Use the work rate that corresponds to this MET value to determine highest exercise level. 2.5. Cycle ergometer protocol 2.5.1. To calculate the ˙ V o 2 for a given work rate: 1. Calculate the target ˙ V o 2 . 2. ( ˙ V o 2 ,target – ˙ V o 2 ,unloaded)/10=work rate, wherework rate is inwatts, ˙ V o 2 inml/min (73). 3. Use this work rate to determine highest exercise level.

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