Health, Exercise, and Sports Sciences ETDs

Publication Date

Summer 7-17-2023

Abstract

Sodium bicarbonate supplementation (NaHCO3) before physical work in the heat may reduce the risk of developing acute kidney injury (AKI). Purpose: To determine the effects of NaHCO3 supplementation before a prolonged bout of physical work in the heat on AKI markers and kidney function. Method: A randomized, cross-over, double blinded design was conducted on 8 participants (3 females) who consumed NaHCO3 (0.2 g/kg body weight) or placebo (CON) before prolonged (120 minutes) moderate intensity (~65% of maximal heart rate) physical work in the heat [40℃ and 23% relative humidity (RH)]. Blood and urine samples were collected pre, post, and 1hr post exercise. Core temperature and heart rate were measured every three minutes, and perceptual variables were measured every 6 minutes. Gastrointestinal discomfort (GI) was evaluated pre- and post NaHCO3 or CON ingestion, within 1hr, post, and 1hr post the physical work. Urine flow rate (UFR) was calculated pre and 1hr post physical work. Urine osmolality (Uosm) and creatinine (uCr) and plasma osmolality (Posm) were assessed pre, post, and 1hr post physical work. Insulin-like growth factor binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinase 2 (TIMP-2) were measured in the urine pre and 1hr post physical work. Results: Physiological, perceptual, and GI parameters increased over time (p < 0.05) but were not different between conditions (p > 0.05). Uosm was higher in CON compared to NaHCO3 (p = 0.011) post exercise. UFR was lower in CON compared to NaHCO3 at 1 hour post exercise (p = 0.042). Urine TIMP-2 corrected for UFR was higher in CON compared to NaHCO3 (p =0.040). Log IGFBP-7 × TIMP-2 was lower in NaHCO3 (p = 0.02). Conclusion: NaHCO3 ingestion pre-physical work in the heat reduced markers of AKI and increased UFR suggesting less stress to the kidneys.

Keywords

Heat, sodium bicarbonate, acute kidney injury, kidney function, physical work, exercise

Document Type

Dissertation

Language

English

Degree Name

Physical Education, Sports and Exercise Science

Level of Degree

Doctoral

Department Name

Health, Exercise, and Sports Sciences

First Committee Member (Chair)

Dr. Fabiano Amorim

Second Committee Member

Dr. Christine Mermier

Third Committee Member

Dr. Michael Deyhle

Fourth Committee Member

Dr. Zidong Li

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