ACSM[042-082]

CHAPTER 3 Pre-Exercise Evaluations 51
cholesterol and in the kidneys to lower blood pressure. One should pay particular
attention to liver function tests such as alanine transaminase (ALT), aspartate
transaminase (AST), and bilirubin as well as to renal (kidney) function tests such
as creatinine, glomerular filtration rate, blood urea nitrogen (BUN), and BUN/
creatinine ratio in patients on such medications. Indication of volume depletion and
potassium abnormalities can be seen in the sodium and potassium measurements.
These tests should be applied judiciously and not used as finite ranges of normal.
PULMONARY FUNCTION
Pulmonary function testing with spirometry is recommended for all smokers
older than age 45 years and in any person presenting with dyspnea (shortness of
breath), chronic cough, wheezing, or excessive mucus production (5). Spirometry
is a simple and noninvasive test that can be performed easily. Indications for
spirometry are listed in Table 3.4. When performing spirometry, standards for the
performance of the test should be followed (9).
Although many measurements can be made from a spirometric test, the most
commonly used include the forced vital capacity (FVC), the forced expiratory
volume in one second (FEV 1 ), and the FEV 1 /FVC ratio. Results from these
measurements can help to identify the presence of restrictive or obstructive respiratory
abnormalities, sometimes before symptoms or signs of disease are present.
The FEV 1 /FVC is diminished with obstructive airway diseases [e.g.,
asthma, chronic bronchitis, emphysema, and chronic obstructive pulmonary
disease (COPD)], but remains normal with restrictive disorders (e.g., kyphoscoliosis,
neuromuscular disease, pulmonary fibrosis, and other interstitial lung
diseases).
The Global Initiative for Chronic Obstructive Lung Disease has classified the
presence and severity of COPD as seen in Table 3.4 (12). The term COPD can be used
when chronic bronchitis, emphysema, or both are present, and the spirometry documents
an obstructive defect. A different approach for classifying the severity of
obstructive and restrictive defects has been taken by the American Thoracic Society
(ATS) and European Respiratory Society (ERS) Task Force on Standardization of
Lung Function Testing, as presented in Table 3.4 (13). This ATS/ERS Task Force
prefers to use the largest available vital capacity (VC), whether it is obtained on
inspiration (IVC), slow expiration (SVC), or forced expiration (FVC). An obstructive
defect is defined by a reduced FEV 1 /VC ratio below the fifthpercentile of the predicted
value. In contrast with using a fixed value for FEV 1 /VC or FEV 1 /FVC of 0.7
as the dividing line between normal and abnormal, the use of the fifth percentile of
the predicted value as the lower limit of normal does not lead to an overestimation
of the presence of an obstructive defect in older people. A restrictive defect is characterized
by a reduction in the total lung capacity (TLC), as measured on a lung volume
study, below the fifth percentile of the predicted value, and a normal FEV 1 /VC.
The spirometric classification of lung disease has been useful in predicting
health status, use of health resources, and mortality. Abnormal spirometry can
also be indicative of an increased risk for lung cancer, heart attack, and stroke
and can be used to identify patients in which interventions, such as smoking
cessation and use of pharmacologic agents, would be most beneficial.