Method To Measure Protein Digestion & Absorption

IInclusion and exclusion criteria for study participation: We will enroll subjects (males and females of all races) based on the inclusion/exclusion criteria described below. All subjects should be able to walk, sit and stand up indepedently. Screening procedures will be done prior to the study. Inclusion criteria - CHF subjects: * Ability to walk, sit down and stand up independently * Age 45 years or older * Ability to lie in supine or elevated position for 9 hours * Diagnosis of CHF; under regular care by cardiologist * Reduced ejection fraction (\<45%) assessed in the past 2 years * NYHA class II-IV * Clinically stable condition; no hospitalization 4 weeks preceding first study day * Willingness and ability to comply with the protocol Inclusion criteria - COPD subjects: * Ability to walk, sit down and stand up independently * Age 45 years or older * Ability to lie in supine or elevated position for 8 hours * Diagnosis of moderate to very severe chronic airflow limitation and compliant to the following criteria: FEV1 \< 70% of reference FEV1 * Clinically stable condition and not suffering from a respiratory tract infection or exacerbation of their disease (defined as a combination of increased cough, sputum purulence, shortness of breath, systemic symptoms such as fever, and a decrease in FEV1 \> 10% compared with values when clinically stable in the preceding year) at least 4 weeks prior to the first test day * Shortness of breath on exertion * Willingness and ability to comply with the protocol Inclusion criteria - healthy subjects: * Healthy male \& female according to the investigator's or appointed staff's judgment * Age 45 years and older, or 20 - 30 for healthy young group Exclusion Criteria - all subjects: * Any condition that may interfere with the definition 'healthy subject' according to the investigator's judgment (healthy subjects only) * Established diagnosis of malignancy * History of untreated metabolic diseases including hepatic or renal disorder * Presence of acute illness or metabolically unstable chronic illness * Presence of fever within the last 3 days * Body mass index \>40 kg/m2 (healthy subjects only) * Any other condition according to the PI or nurse that was found during the screening visit, that would interfere with the study or safety of the patient * Use of protein or amino acid containing nutritional supplements within 5 days prior first study day * Current Use of long-term oral corticosteroids (CHF only) * Use of short course of oral corticosteroids within 4 weeks preceding first study day * Failure to give informed consent or Investigator's uncertainty about the willingness or ability of the subject to comply with the protocol requirements * (Possible) pregnancy * Already enrolled in another clinical trial and that clinical trial interferes with participating in this study