Must be able to complete an acceptable cardiopulmonary exercise test (CPET) at baseline defined as at least one of the following:\r\n* Achieving a plateau in oxygen consumption concurrent with an increase in power output;\r\n* Respiratory exchange ratio >= 1.1 (RER);\r\n* Volitional exhaustion with a rating of perceived exertion >= 17 (RPE) Must be able to complete an acceptable cardiopulmonary exercise test (CPET) at baseline, defined as at least one of the following:\r\n* Achieving a plateau in oxygen consumption concurrent with an increase in power output\r\n* Respiratory exchange ratio >= 1.1 (RER)\r\n* Volitional exhaustion with a rating of perceived exertion >= 17 (RPE) Able to achieve and complete an acceptable cardiopulmonary exercise test defined as follows: achieving peak or plateau in oxygen consumption concurrent with increased power output; a respiratory exchange ratio >= 1.1 or volitional exhaustion-rating of perceived exertion > 19 Able to achieve an acceptable peak baseline CPET, as defined by any of the following criteria:\r\n* Achieving a plateau in oxygen consumption, concurrent with an increase in power output\r\n* A respiratory exchange ratio >= 1.10\r\n* Attainment of maximal predicted heart rate (HR max) (i.e., within 10 beats per minute [bpm] of age-predicted HR max [HR max = 220-Age[years])\r\n* Volitional exhaustion, as measured by a rating of perceived exertion (RPE) >= 18 on the BORG scale Able to achieve an acceptable peak baseline CPET, as defined by any of the following criteria:\r\n* Achieving a plateau in oxygen consumption, concurrent with an increase in power output;\r\n* A respiratory exchange ratio >= 1.10;\r\n* Attainment of maximal predicted heart rate (HRmax) (i.e., within 10 beats per minute [bpm] of age-predicted HRmax);\r\n* Volitional exhaustion, as measured by a rating of perceived exertion (RPE) >= 18 on the BORG scale Able to achieve an acceptable peak baseline CPET, as defined by any of the following criteria:\r\n* Achieving a plateau in oxygen consumption, concurrent with an increase in power output\r\n* A respiratory exchange ratio >= 1.10\r\n* Attainment of maximal predicted heart rate (maximum heart rate [HRmax])\r\n* Volitional exhaustion, as measured by a rating of perceived exertion (RPE) >= 18 on the BORG scale Able to achieve an acceptable peak baseline CPET, as defined by any of the following criteria:\r\n* Achieving a plateau in oxygen consumption, concurrent with an increase in power output;\r\n* A respiratory exchange ratio >= 1.10;\r\n* Attainment of maximal predicted heart rate (HRmax) (i.e., within 10 beats per minute (bpm) of age-predicted HRmax;\r\n* Volitional exhaustion, as measured by a rating of perceived exertion (RPE) >= 18 on the Borg scale Able to achieve an acceptable peak baseline CPET, as defined by any of the following criteria:\r\n* Achieving a plateau in oxygen consumption, concurrent with an increase in power output;\r\n* A respiratory exchange ratio of >= 1.10;\r\n* Attainment of maximal predicted heart rate (HRmax) (i.e., within 10 beats per minute [bpm] of age-predicted HRmax);\r\n* Volitional exhaustion, as measured by a rating of perceived exertion (RPE) >= 18 on the BORG scale Intrinsic lung disease resulting in dyspnea No evidence of dyspnea at rest Symptomatic intrinsic lung disease or extensive tumor involvement of the lungs, resulting in dyspnea at rest No clinical indications such as evidence of dyspnea at rest, or exercise intolerance due to pulmonary insufficiency Symptomatic intrinsic lung disease or extensive tumor involvement of the lungs resulting in dyspnea at rest EXCLUSION CRITERIA FOR REGISTRATION: Symptomatic intrinsic lung disease or extensive tumor involvement of the lungs resulting in dyspnea at rest Within 4 weeks prior to study enrollment: No evidence of dyspnea at rest Adequate pulmonary function defined as no evidence of dyspnea at rest No evidence of dyspnea at rest No evidence of dyspnea at rest and no exercise intolerance No evidence of dyspnea at rest No evidence of dyspnea at rest, and No evidence of dyspnea at rest Patients must have clinically normal lung function as manifested by no dyspnea at rest and no oxygen requirement Intrinsic lung disease resulting in moderate to severe dyspnea Lung disease resulting in dyspnea at rest. Normal lung function as manifested by no dyspnea at rest and no oxygen requirement Dyspnea with moderate exertion No evidence of dyspnea at rest Symptomatic intrinsic lung disease or extensive tumor involvement of the lungs resulting in dyspnea at rest Evidence of dyspnea at rest or oxygen saturation (<=) 94 percent (%). Normal lung function with no dyspnea at rest, pleural effusion or oxygen requirement No dyspnea at rest No evidence of dyspnea at rest Symptomatic intrinsic lung disease or extensive tumor involvement of the lungs, resulting in dyspnea at rest Intrinsic lung disease resulting in dyspnea Symptomatic intrinsic lung disease or extensive tumor involvement of the lungs, resulting in grade 2 or higher dyspnea at rest Dyspnea with moderate exertion Symptomatic intrinsic lung disease or extensive tumor involvement of the lungs, resulting in dyspnea at rest REGISTRATION EXCLUSION CRITERIA: Symptomatic intrinsic lung disease or extensive tumor involvement of the lungs resulting in dyspnea at rest No evidence of dyspnea at rest Symptomatic intrinsic lung disease or extensive tumor involvement in the lungs resulting in dyspnea at rest At least moderate dyspnea defined by a BDI score of 6 or less in the self-administered computerized versions of the baseline and transition dyspnea indexes (SAC-BDI/TDI); (this cutoff score is close to the score of 5.7 used to define \moderate dyspnea\ in the publication that validated the instrument and is selected by attending physicians in the pulmonary service as a good indication of \ moderate dyspnea\ in clinical practice; a typical person with BDI of 6, for example, would be a 52 year old woman who has to pause when walking because of dyspnea and/or has eliminated doing an activity because of dyspnea) Symptomatic intrinsic lung disease or extensive tumor involvement of the lungs, resulting in dyspnea at rest Dyspnea with an average intensity >= 4 on the dyspnea NRS (range 0-10) over the past week. Dyspnea numeric rating scale at rest >= 3 of 10 (average over last 24 hour) Breakthrough dyspnea, defined as dyspnea with an average intensity level over the past 7 days of at least 3/10 on a numeric rating scale upon significant exertion or continuous dyspnea =< 7/10 with worsening upon significant exertion Dyspnea at rest >= 7/10 at the time of enrollment Patients with ESAS > 4/10 on dyspnea Subject has a history of at least 1 ipsilateral pleural effusion causing dyspnea that responded to thoracentesis where the lung expanded and the dyspnea was improved. Breakthrough dyspnea, defined in this study as dyspnea on exertion with an average intensity level >= 3/10 on the numeric rating scale Dyspnea at rest >= 7/10 at the time of enrollment Breakthrough dyspnea, defined in this study as dyspnea on exertion with an average intensity level >= 3/10 on the numeric rating scale Dyspnea at rest >= 7/10 at the time of enrollment