Article Title



Liliana I. Renteria1, Brandon D. Willingham2, Ericka M. Biagioni3, Matthew J. Poland1, Casey E. Greenwalt1, Michael J. Ormsbee, FACSM1. 1Florida State University, Tallahassee, FL. 2Coastal Carolina University, Conway, SC. 3East Carolina University, Greenville, NC.

BACKGROUND: Exercising in the heat for long durations increases the risk of heat-related illnesses and declines performance. Research suggests betaine (BET)—found in wheat and beets—can act as an osmoprotectant, making cells and animals more resilient to thermal and hypertonic stress. Most of the research in this area has been conducted in passive heat settings using animal models, making the present pilot data novel to the body of research. The aim of this study was to assess how preloaded BET supplementation impacts humans undergoing active heat stress (i.e., cycling in the heat). METHODS: Six endurance trained men (Mean±SD: 23.3±2.6 yrs, 179.23±5.5 cm, 70.4±9.3 kg, VO2MAX 54.4±3.3 ml/kg/min) completed a double-blind crossover design study in which participants supplemented with BET (50 mg/kg 2x/day) or a rice flour placebo (PLA; 50 mg/kg 2x/day) for 7 days before completing the experimental protocol. Participants then underwent a 7-day washout period and crossed over into the alternate condition. They were asked to consume 6 ml/kg of water with each dose and drink ad libitum the rest of the day. On days 0 and 7 of each condition, participants arrived fasted from calories (7-9 hr), caffeine (12 hr), as well as alcohol and exercise (24 hr). The experimental protocol involved cycling at 70% VO2MAX for 1 hr and completing a time to exhaustion trial against 130% peak power output in the heat (33°C, 35% RH). A Shapiro Wilks test was used to establish normality and a paired samples t-test was used to determine significance. RESULTS: Ending core temperature was significantly lower in BET (38.1±0.5°C) compared to PLA (38.3±0.5°C; p=0.01). No significance was detected for changes in plasma osmolality after the active heat load in BET (Pre 289.0±3.4 mmol/L; Post 289.4±1.9 mmol/L; p=0.79), however there was a significant decrease in PLA (Pre 289.1±4.7 mmol/L; Post 283.8±4.8 mmol/L; p=0.04). Despite a mean increase in intracellular fluid (+1.15 L) in BET, it was not significantly different from the decrease (-0.37 L) observed in PLA (p=0.08). There were no significant differences in sprint duration between groups (p=0.67). CONCLUSION: In this pilot study, 7 days of BET supplementation maintained plasma osmolality and may potentially mitigate increased core temperature after 1 hr of exhaustive exercise in the heat without significant changes to intracellular fluid. This study was funded by NOW Foods.

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