Impact of sodium citrate ingestion during recovery after dehydrating exercise on rehydration and subsequent 40-km cycling time-trial performance in the heat

Abstract

The purpose of this study was to assess the impact of sodium citrate (CIT) ingestion (600 mg·kg) during recovery from dehydrating cycling exercise (DE) on subsequent 40-km cycling performance in a warm environment (32 °C). Twenty male nonheat-acclimated endurance athletes exercised in the heat until 4% body mass (BM) loss occurred. After 16 h recovery with consumption of water ad libitum and prescribed diet (evening meal 20 kcal·kg, breakfast 12 kcal·kg) supplemented in a double-blind, randomized, crossover manner with CIT or placebo (PLC), they performed 40-km time-trial (TT) on a cycle ergometer in a warm environment. During recovery greater increases in BM and plasma volume (PV) concomitant with greater water intake and retention occurred in the CIT trial compared with the PLC trial (p < 0.0001). During TT there was greater water intake and smaller BM loss in the CIT trial than in the PLC trial (p < 0.05) with no between-trial differences (p > 0.05) in sweat loss, PV decrement, ratings of perceived exertion, or TT time (CIT 68.10 ± 3.28 min, PLC 68.11 ± 2.87 min). At the end of TT blood lactate concentration was higher (7.58 ± 2.44 mmol·L vs 5.58 ± 1.32 mmol·L; p = 0.0002) and rectal temperature lower (39.54 ± 0.50 °C vs 39.65 ± 0.52 °C; p = 0.033) in the CIT trial than in the PLC trial. Compared with pre-DE time point, PV had decreased to a lower level in the PLC trial than in the CIT trial (p = 0.0001). In conclusion, CIT enhances rehydration after exercise-induced dehydration but has no impact on subsequent 40-km cycling TT performance in a warm uncompensable environment.

Sodium citrate supplementation: An updated revision and practical recommendations on exercise performance, hydration status, and potential risks

“…Similarly to the Timpmann study, 67 participants consumed SC (0.6 g × kg −1 bw) in a 16 hours rest period after losing 4% of their bw through exercise in the heat, and before 40 km TT the plasma volume was 7.8% higher in the SC group compared to 0.9% observed in the placebo group. Therefore, SC ingestion during 16 hours recovery period enhanced rehydration, promoted water retention, and increased plasma volume but had no effect on thermoregulation and 40 km cycling TT performance in dehydrated endurance athletes in warm environment 70 . Furthermore, a very recent study by Suvi with the same experimental data of 2018 pointed out that a change in aldosterone secretion may arise from SC supplementation before, during, and after exercise even in absence of a significant improvement in performance 34 .…”

“…Even in this case, the supplementation was not associated with significant increase in performance measured as peak power. As enhanced plasma volume may improve endurance performance by fighting against the increase in core body temperature, 69 recent studies investigated the potential benefits of SC ingestion in endurance sports performed in warm environmental conditions 34,48,70 . Mora‐Rodriguez and Hamouti focused on the importance of pre‐exercise plasma volume expansion in endurance performance following the ingestion of saline solutions and showed that acute plasma volume expansion in the range of 7%‐8% can improve performance of 20% on average 69 .…”

“…Mora‐Rodriguez and Hamouti focused on the importance of pre‐exercise plasma volume expansion in endurance performance following the ingestion of saline solutions and showed that acute plasma volume expansion in the range of 7%‐8% can improve performance of 20% on average 69 . Suvi et al, for the first time, studied the impact of SC ingestion on cycling performance during 40 km of TT in a warm environment 70 . Similarly to the Timpmann study, 67 participants consumed SC (0.6 g × kg −1 bw) in a 16 hours rest period after losing 4% of their bw through exercise in the heat, and before 40 km TT the plasma volume was 7.8% higher in the SC group compared to 0.9% observed in the placebo group.…”

Influence of Sodium Citrate Supplementation after Dehydrating Exercise on Responses of Stress Hormones to Subsequent Endurance Cycling Time-Trial in the Heat

“…Considering that resting periods between consecutive stages are rather short, the quality of recovery becomes an especially important factor in determining the ability of an athlete to maintain high level performance over several days or even weeks of a competition. A recent publication [35] revealed that CIT ingestion after dehydrating exercise (DE) effectively stimulated rehydration, but still did not enhance performance during subsequent heavy exercise bout in the heat. In this paper, which is based on unpublished data collected in the same experimental study [35], we focus on the potential impact of CIT ingestion on the levels of stress hormones.…”

“…A recent publication [35] revealed that CIT ingestion after dehydrating exercise (DE) effectively stimulated rehydration, but still did not enhance performance during subsequent heavy exercise bout in the heat. In this paper, which is based on unpublished data collected in the same experimental study [35], we focus on the potential impact of CIT ingestion on the levels of stress hormones. By increasing the body’s buffer capacity [6,9] and PV [9,10], CIT may facilitate maintenance of homeostasis, i.e., reduce physiological stress, during heavy exercise in the heat.…”