Restrictive lung disease is typically associated with FEV1 and FVC values of:

Restrictive lung disease is characterized by a reduced ability to expand the lungs, leading to decreased total lung capacity. As a result, both Forced Expiratory Volume in one second (FEV1) and Forced Vital Capacity (FVC) will be lower than normal. However, the FEV1/FVC ratio is typically preserved or may be increased.

In the context of this question, when the FEV1 and FVC values are described as being less than 80%, it reflects the impairment seen in restrictive lung disease. Values below this threshold indicate significant lung function deterioration due to restriction from factors such as interstitial lung diseases, pulmonary fibrosis, or chest wall abnormalities.

Understanding this, it becomes clear that a measurement of less than 80% for both FEV1 and FVC is indicative of restrictive pathology, reinforcing the classification of such lung diseases based on objective pulmonary function tests.