The purpose of our study was to validate a newly developed breath acetone (BrAce) analyzer. and to explore if BrAce could predict aerobic exercise-related substrate use. Six healthy men ran on a treadmill at 70% of maximal oxygen consumption (VO2max) for 1 h after two days of a low-carbohydrate diet. BrAce and blood ketone (acetoacetate (ACAC). https://www.spidertattooz.com/WAC-4011-LED-Horizontal-Step-Light-Colorscaping/