2.1. Subjects

Eight healthy older individuals (>60 years) were recruited by using flyers posted around the Little Rock area and the University of Arkansas for Medical Sciences (UAMS) campus (September 2015 through January 2016). Subject eligibility for the study was accessed based on a battery of medical tests including liver and renal function, plasma electrolytes, blood glucose concentration, and medical history tests. Exclusion criteria precluded participants with active malignancy within the past 6 months, a chronic inflammatory disease, diabetes, low hematocrit or hemoglobin concentration, gastrointestinal bypass surgery, low platelets, concomitant use of corticosteroids, and any unstable medical conditions. In addition, participants who performed any types of strenuous physical activity more than once a week were excluded. Prior to study initiation, the ethics committee of the Institutional Review Board at the UAMS approved this study (IRB# 204291) which was performed in accordance with the Declaration of Helsinki and written informed consent was obtained from all subjects. Clinical Trial Registry number and website: {"type":"clinical-trial","attrs":{"text":"NCT03765710","term_id":"NCT03765710"}}NCT03765710, https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S0008HGW&selectaction=Edit&uid=U0003YFM&ts=2&cx=9zc687.