This study is designed to make sure exercise equipment used by the National Heart, Lung, and Blood Institute is working properly. Healthy volunteers will be requested to use P-CCMB cardiopulmonary exercise equipment (treadmills and exercise bicycles) two times a month to ensure the machines are functioning properly.

Proper functioning of recently acquired P-CCMB cardiopulmonary exercise equipment will be verified by testing healthy volunteers. In addition, quality control will be verified by performing monthly testing of healthy volunteers as biologic standards.

INCLUSION:

Healthy research volunteers who are between 21 and 65 years.

EXCLUSION:

Patients with a history of ischemic or valvular heart disease.

Patients with history of chronic pulmonary disease.

Pregnant women.