Acute Beetroot Juice Supplementation and Repeated Maximal Effort in Elite Swimmers: A Randomized Double-Blind Study

Beetroot juice (BRJ) has been proposed as an ergogenic aid due to its high nitrate content, yet evidence from field-based studies in elite swimmers remains limited. This study investigated the acute effects of concentrated BRJ ingestion on performance and physiological responses during repeated maximal 200-m front-crawl efforts in elite male swimmers. Twelve elite swimmers (age: 20 ± 2 years, body fat: 7.1% ± 2.5%, 200-m personal best: 115.7 ± 3.4 s) completed a randomized, double-blind, counterbalanced trial. Participants consumed either 140 ml of concentrated BRJ (Beet It Sport) or a custom-made, nitrate-depleted placebo (PL) matched for sensory characteristics, 2 hr before performing two maximal 200-m front-crawl time trials, separated by 60 min of passive recovery. Blood samples were collected upon arrival and immediately after each time trials, and 200-m completion time, blood lactate concentrations, and ratings of perceived exertion were recorded. No significant differences were observed in completion time for either the first (PL: 116.7 ± 3.0 vs. BRJ: 117.2 ± 3.1 s, p = .19) or the second 200-m time trial (PL: 117.8 ± 2.6 vs. BRJ: 117.8 ± 3.3 s, p = .98), nor in the change between trials (PL: 1.1 ± 1.5 vs. BRJ: 0.5 ± 1.3 s, p = .40). Likewise, lactate concentrations and ratings of perceived exertion values did not differ between conditions (p > .05). In conclusion, acute BRJ supplementation did not enhance 200-m front-crawl performance, lactate responses, or perceived exertion in elite swimmers under competition-like conditions.