Neither an Individualised Nor a Standardised Sodium Bicarbonate Strategy Improved Performance in High-Intensity Repeated Swimming, or a Subsequent 200 m Swimming Time Trial in Highly Trained Female Swimmers.

Inconsistent swimming performances are often observed following sodium bicarbonate (NaHCO) ingestion, possibly because the time taken to reach peak blood buffering capacity is highly variable between individuals. Personalising NaHCO ingestion based on time-to-peak blood bicarbonate (HCO) could be a solution; however, this strategy is yet to be explored in swimming, or adequately compared to standardised NaHCO approaches. Therefore, six highly trained female swimmers ingested 0.3 g·kg BM NaHCO in capsules to pre-determine their individual time-to-peak blood HCO. They then participated in three experimental trials, consisting of a 6 × 75 m repeated sprint swimming test, followed by a 200 m maximal time trial effort after 30 min active recovery. These experiments were conducted consuming a supplement at three different timings: individualised NaHCO (IND: 105-195 min pre-exercise); standardised NaHCO (STND: 150 min pre-exercise); and placebo (PLA: 90 min pre-exercise). Both NaHCO strategies produced similar increases in blood HCO prior to exercise (IND: +6.8 vs. STND: +6.1 mmol·L, < 0.05 vs. PLA) and fully recovered blood HCO during active recovery (IND: +6.0 vs. STND: +6.3 mmol·L vs. PLA, < 0.05). However, there were no improvements in the mean 75 m swimming time (IND: 48.2 ± 4.8 vs. STND: 48.9 ± 5.8 vs. PLA: 49.1 ± 5.1 s, = 0.302) nor 200 m maximal swimming (IND: 133.6 ± 5.0 vs. STND: 133.6 ± 4.7 vs. PLA: 133.3 ± 4.4 s, = 0.746). Regardless of the ingestion strategy, NaHCO does not appear to improve exercise performance in highly trained female swimmers.