Effect of Acute and Chronic Sodium Bicarbonate Supplementation on Prolonged Running Performances Under Hot Conditions in Trained Athletes

Gee, Yong Yong (2024) Effect of Acute and Chronic Sodium Bicarbonate Supplementation on Prolonged Running Performances Under Hot Conditions in Trained Athletes. Masters thesis, Tunku Abdul Rahman University of Management and Technology.

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Abstract

While the effect of sodium bicarbonate (NaHCO3 or SB) on buffering capacity has been extensively studied in short-term and high-intensity exercise performance, there has been little research on long-term endurance performance such as running in hot conditions. Thus, this study aimed to examine whether acute or chronic NaHCO3 ingestion would improve endurance sports performance under hot conditions in trained athletes. Exercise in hot environmental conditions tends to have a higher blood lactate level. The ingestion of NaHCO3 is plausible to improve endurance sports performance under hot conditions that reflect Malaysia's climate. The International Society of Sports Nutrition (ISSN) has yet to provide any information regarding the impact of NaHCO3 supplementation on exercise performance in hot conditions. Consequently, the effects of this supplementation remain unclear. A total of 10 trained male runners (age: 21.3 ± 1.3) years; weight: 59.4 ± 5.2 kg; height: 169.3 ± 4.8 cm; VO2max 57.2 ± 5.3 ml.kg-1.min-1) were recruited in this study. Participants undertook 1 preliminary testing and 4 experimental trials in a randomised order under hot conditions (32°C) which consisted of: (i) Acute - NaHCO3 (0.3 g.kg-1 BW) 90-min prior to prolonged endurance testing (PET); (ii) Chronic - NaHCO3 (0.5 g.kg-1 BW) for 5 consecutive days (0.1 g.kg-1 per day) prior to PET; (iii) Acute - placebo (PLA) - 0.05 g.kg-1 BW of NaCl 90-min prior to PET; (iv) Chronic - PLA (0.05 g.kg-1 BW) of NaCl for 5 consecutive days (0.01 g.kg-1 per day) prior to PET. The result showed that participants ran faster during the chronic sodium bicarbonate (CSB) trial than the acute sodium bicarbonate (ASB) trial (21.54 ± 2.47 min vs. 22.40 ± 2.57 min; p=0.040) associated with lower heart rate response after the 5 km time trial (CSB: 192 ± 11 vs. ASB: 196 ± 10 beats.min-1). No significant difference was found between ASB and CSB supplementation in (ASB: 12.94 ± 4.71 mmol.L-1; CSB: 10.83 ± 2.56 mmol.L-1; p> 0.05) and core temperature (ASB:39.31 ± 0.24 ℃; CSB: 38.97 ± 0.45 ℃; p> 0.05) during PET trials. In addition, two participants perceived ‘slight discomfort’, and one participant perceived ‘moderate discomfort’ after PET in the ASB trial, whereas the feelings of abdominal discomfort and GUT fullness in the CSB trial were very minimal. In conclusion, a total of 0.5 g.kg-1 BW NaHCO3 chronic ingestion of 5 consecutive days prior to PET trial improved prolonged running performance under hot conditions with no gastrointestinal symptoms.