AECOPD and Nutritional Supplementation in COPD

Inclusion criteria COPD exacerbation (AECOPD) group: * Between age 45 and older * Experiencing an acute exacerbation of COPD (defined as a combination of symptoms such as 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 years) and admitted at College Station Medical Center (with expected stay less than 10 days) or staying at home. * Willingness and ability to comply with the protocol, including: * Adhering to fasting state from 10 pm ± 2h onwards the day prior to each study visit * Ability to lie in supine or elevated position for 4 hours Inclusion criteria stable COPD subjects: * Ability to walk, sit down and stand up independently * Between age 45 and older * 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 at least 4 weeks prior to the first test day * Shortness of breath on exertion * Willingness and ability to comply with the protocol, including: * Adhering to fasting state from 10 pm ± 2h onwards the day prior to each study visit * Ability to lie in supine or elevated position for 4 hours Inclusion criteria healthy control subjects: * Healthy male or female according to the investigator's or appointed staff's judgment * Ability to walk, sit down and stand up independently * Between age 45 and older * No diagnosis of chronic airflow limitation * Willingness and ability to comply with the protocol, including: * Adhering to fasting state from 10 pm ± 2h onwards the day prior to each study visit * Ability to lie in supine or elevated position for 4 hours Exclusion Criteria all subjects: * Any condition that may interfere with the definition 'healthy subject' according to the investigator's judgment (for healthy control group only) * Established diagnosis of malignancy * History of untreated metabolic diseases including hepatic or renal disorder * Presence of other acute metabolic illnesses (ie renal, liver disease) * 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 * Dietary or lifestyle characteristics: * Current alcohol or drug abuse * Known hypersensitivity to fish and/or shellfish, Swanson EFAs Super EPA Fish oil or any of its ingredients, Swanson EFAs Certified Organic Extra Virgin Olive oil or any of its ingredients or Smartfish Nutrifriend or any of its ingredients (AECOPD and stable COPD nutrition groups only) * Use of supplements containing more than 1 g of EPA+DHA 3 months prior to the first test day (AECOPD and stable COPD nutrition groups only) * 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 * Body mass index \<18.5 or \>45 kg/m2 * When during the period from enrollment to completion of the study any condition is developed, whether causing a subject to not meet any of the inclusion criteria or to meet one or more of the exclusion criteria, the study can either be temporarily or permanently stopped for that subject.