Rehydration with a caffeinated beverage during the nonexercise periods of 3 consecutive days of 2-a-day practices.
The purpose of this study was to assess the influence of rehydration with a caffeinated beverage during nonexercise periods on hydration status throughout consecutive practices in the heat. Ten (7 women, 3 men) partially heat- acclimated athletes (age 24 +/-1y, body fat 19.2 +/- 2 %, weight 68.4 +/- 4.0 kg, height 170 +/- 3 cm) completed 3 successive days of 2-a-day practices (2 h/practice, 4 h/d) in mild heat (WBGT = 23 C). The 2 trials (double-blind, random, cross-over design) included; 1) caffeine (CAF) rehydrated with Coca-Cola and 2) caffeine-free (CF) rehydrated with Caffeine-Free Coca-Cola. Urine and psychological measures were determined before and after each 2-h practice. A significant difference was found for urine color for the post-AM time point, F = 5.526, P = 0.031. No differences were found among other variables (P > 0.05). In summary, there is little evidence to suggest that the use of beverages containing caffeine during nonexercise might hinder hydration status.
Department of Kinesiology in the Neag School of Education at the University of Connecticut, Storrs, CT 06269, USA.
Kelly A
KA
Fiala
Douglas J
DJ
Casa
Melissa W
MW
Roti
D000328:Adult; D000704:Analysis of Variance; D002110:Caffeine / Q000008:administration & dosage* / Q000009:adverse effects / Q000378:metabolism / Q000652:urine; D002253:Carbonated Beverages; D000697:Central Nervous System Stimulants / Q000008:administration & dosage* / Q000009:adverse effects / Q000378:metabolism / Q000652:urine; D018592:Cross-Over Studies; D003681:Dehydration / Q000139:chemically induced / Q000209:etiology / Q000517:prevention & control*; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D005260:Female; D005440:Fluid Therapy / Q000379:methods*; D006801:Humans; D008297:Male; D011597:Psychomotor Performance / Q000187:drug effects; D013046:Specific Gravity; D013997:Time Factors; D016482:Urinalysis
D000697:Central Nervous System Stimulants; D002110:Caffeine