Effects of Eight Weeks of Aerobic Training Combined with Carbohydrate Mouth Rinse on Body Composition and Exercise Performance in Adult Men with Obesity: Evidence from Korea.

Background: Considering that the prevalence of obesity has risen rapidly in recent decades, the aim of this study was to investigate the effects of a carbohydrate mouth rinse (CMR) on the outcomes of aerobic training among adult men with obesity, focusing particularly on the effects of repeated use on body composition and exercise performance. Methods: The intervention targeted 20 men with obesity in their 20s and 30s randomly assigned to either a CMR group (n = 10) or a placebo mouth rinse (PMR) group (n = 10). Both groups completed treadmill-based aerobic training three times per week for eight weeks. Prior to each session, participants used a mouth rinse at 60, 40, and 20 s before the start of each exercise, holding either a 6% maltodextrin solution (CMR) or purified water (PMR) in their mouths for 5 to 10 s before expectorating. Pre- and post-intervention assessments included body composition (body weight and body fat percentage), resting metabolic rate (RMR), maximal oxygen uptake (VO₂max), and exercise performance (rate of perceived exertion [RPE], exercise distance, speed, and time). Data were analyzed using 2 × 2 repeated measures analysis of variance. Results: Following the intervention, the CMR group showed significantly greater improvements than the PMR group did in body fat percentage, RMR, VO₂max, exercise distance, speed, and time (p < 0.01). However, the interaction effect for RPE was not statistically significant between the groups (p = 0.175). Overall, the repeated use of the CMR during aerobic training contributed to enhanced exercise performance and favorable physiological changes without additional caloric intake. Conclusions: A CMR may be a practical and non-caloric ergogenic aid to support exercise performance and metabolic function in individuals with obesity. Its repeated use during aerobic training appears to be effective and safe, especially when fasting while exercising, when improving endurance without compromising fat loss is essential.