Background: Alcohol use decreases skeletal muscle (SKM) strength and function. Alcohol use is disproportionately on the rise among older individuals, with 25% engaging in heavy drinking and 11% reporting binge drinking. The significant increase in life expectancy in the United States leads us to predict that alcohol use will be an important factor exacerbating SKM function in chronological aging, increasing the risk of poor physical performance and frailty. The objective of the study was to assess the impact of recent alcohol use on measures of physical performance and on muscle differentiation and bioenergetic capacity among people over the age of 60. Methods: We conducted a prospective cross-sectional study. Sedentary people over the age of 60 years were recruited from the Greater New Orleans Area. Participants were assessed for physical performance and vastus lateralis muscle biopsies taken for biochemical analysis. Recent alcohol misuse was defined as phosphatidyl ethanol (PEth), a biomarker of alcohol use, levels >20 ng/ml. Results: Preliminary analysis of data from 13 participants (PEth> 20 ng/ml, n=5) showed no differences in hand grip strength (Means± SD-31.08±9.8 and 33.17±8.4 kg respectively), 30-sec sit to stand test (10.5± 1.8 and 10.6± 3.9 number respectively), and Timed up and go Test (13.5± 2.6 and 11.4± 3.1 seconds respectively) among participants with PEth < 20 ng/ml compared to those with PEth >20ng/ml. Data collected from myotubes derived from myoblasts isolated from SKM biopsies from participants with PEth >20 ng/ml showed increased proton leak (indicator of poor mitochondrial bioenergetic health) and lower myotube density (p=0.06, Cohen’s d = 1.9) compared to myotubes from participants with PEth <20 ng/ml. Conclusions: Preliminary analysis indicates that recent alcohol use dysregulates muscle bioenergetic and differentiation capacity that are not associated with significant differences in physical performance tests. Ongoing analysis will identify confounding factors, and whether cumulative lifetime alcohol use contributes more significantly to physical performance and frailty measures among older people. R21AA030869, Pilot funding Department of Physiology LSUHSC-NO, P60AA009803. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.