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REHYDRATION WITH FLUIDS CONTAINING BETAINE: RUNNING PERFORMANCE AND METABOLISM IN A 31°C ENVIRONMENT

Armstrong, L E. FACSM1; Roti, M W.1; Hatch, H L.1; Sutherland, J W.1; Mahood, N V.1; Clements, J M.1; Seen, A D.1; Fiala, K A.1; Craig, S A.S.1; Casa, D J. FACSM1; Maresh, C M. FACSM1

Medicine & Science in Sports & Exercise: May 2003 - Volume 35 - Issue 5 - p S311
G-15F FREE COMMUNICATION/SLIDE THIRST, BEVERAGE COMPOSITION, AND HYDRATION
Free

1Human Performance Laboratory, University of Connecticut, Storrs, CT

The osmolyte betaine offers interesting promise as an ingredient in rehydration fluids.

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PURPOSE

To compare the effects of rehydration with betaine, versus other fluids, on running performance, metabolism, and blood constituents.

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METHODS

Ten male runners (mean±SE age, 20.1±0.6y; body mass, 70.6±2.3kg; VO2max, 63.5±1.4ml/kg/min) were studied using a double-blind, randomized, crossover design. Subjects participated in four controlled tests, using a different rehydration solution during each: 6% carbohydrate-electrolyte fluid replacement beverage (C); C+5g betaine (C+B); a non-nutritive, flavored placebo beverage (P); or P+5g betaine (P+B). Runners dehydrated to −2.7±0.1% body weight overnight, performed morning exercise, then rehydrated to −1.3% body weight. Treadmill trials (75 min, 65%VO2max) in 31°C heat included a timed sprint to exhaustion (90%VO2max).

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RESULTS

There were no significant between- treatment differences in diet, hydration indices, sprint time to exhaustion, rectal temperature, skin temperature, heart rate, sweat rate, and ratings of perceived exertion, thermal sensation, or thirst. In trial C+B (228±58 sec) versus C (196±40 sec), sprint time to exhaustion approached significance (P=.09). Further, a significant increase in plasma lactate and in oxygen consumption (C+B >C, p < .05) occurred during the sprint (lactate and VO2) and 15-min post- sprint (lactate). Regarding the two placebo trials, betaine induced plasma volume expansion after resting rehydration (P+B >P, p < .05); during exercise, this state was reversed (P >P+B, p < .05).

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CONCLUSION

Addition of betaine (5g/L) to C resulted in (a) a 32 sec improvement in mean sprint time to exhaustion (C+B versus C, P > .05, NS), and (b) evidence of enhanced anaerobic and aerobic metabolism, despite sprinting at an identical treadmill speed. Rehydration with the osmolyte betaine also resulted in differential plasma volume changes (P+B versus P) at rest and during exercise. Supported by Danisco USA Inc.

©2003The American College of Sports Medicine