Effect of Beetroot Juice on Anaerobic Performance and Exertion in Adolescent Male Swimmers: Single-Blind Placebo-Controlled Study

Background Beetroot juice (BRJ), rich in nitrate (NO3 ⁻ ), is recognized as an ergogenic aid for enhancing sports performance, yet its effects on swimming remain underexplored. This study investigated the impact of BRJ on anaerobic performance, lactate levels, and exertion in male adolescent swimmers. Fourteen competitive male swimmers (mean age 14.50 ± 0.94 years) consumed BRJ (250 mL, 8 mmol NO3 ⁻ ) or placebo (250 mL, 0.6 mmol NO3 ⁻ ) beverages 2.5 hours before training sessions over six days. Performance was evaluated using an 8 × 100 m freestyle time trial at maximum effort, with blood lactate levels and perceived exertion assessed pre- and post-intervention. Results The BRJ group had significantly faster mean times for the third 100 m interval compared to the placebo group (p < 0.05). While BRJ did not significantly alter blood lactate levels (p > 0.05), it significantly reduced perceived exertion (p < 0.05). Conclusion These findings suggest that six days of BRJ enhances anaerobic swimming performance and reduces exertion in swimmers, though its effect on lactate accumulation is negligible. Future research should explore BRJ's influence on performance and exertion using diverse performance tests and by monitoring blood nitrate levels to better understand its ergogenic potential. This study was registered at ClinicalTrials.gov NCT06461117.