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Rapid IV versus oral rehydration: responses to subsequent exercise heat stress.
Med Sci Sports Exerc. 2006 Dec; 38(12):2125-31.MS

Abstract

PURPOSE

This study sought to determine the effect of rapid intravenous (IV) versus oral (ORAL) rehydration immediately after dehydration, on cardiovascular, thermoregulatory, and perceptual responses during subsequent exercise in the heat.

METHODS

Eight males (21.4 +/- 0.7 yr; 176.2 +/- 1.6 cm; 75.2 +/- 3.7 kg; 63.7 +/- 3.6 mL.kg.min VO2max, 9.0 +/- 1.7% fat) participated in three randomized trials. Each trial consisted of a 75-min dehydration phase (36 degrees C; 42.5% rh, 47 +/- 0.9% VO2max) where subjects lost 1.7 L (IV and no-fluid (NF) trials) to 1.8 L of fluid (ORAL trial). In the heat, fluid lost was matched with 0.45% saline in 20 min by either IV or ORAL rehydration; no fluid was given in the NF trial. Subjects then performed a heat-tolerance test (HTT; 37.0 degrees C, 45% rh, treadmill speed of 2.4 m.s, 2.3% grade) for 75 min or until exhaustion (Tre of 39.5 degrees C). During the HTT, thermal and thirst sensations, RPE, rectal temperature (Tre), heart rate (HR), and mean weighted skin temperature (Tsk) were measured.

RESULTS

Plasma volume in the IV treatment was greater (P < 0.05) after rehydration compared with ORAL and NF. However, during the HTT there were no overall differences (P > 0.05) in HR, Tre, Tsk, RPE, thermal sensations, or HTT time (ORAL, 71 +/- 8 min; IV, 73 +/- 5 min; NF, 39 +/- 29 min) between the ORAL and IV treatments. Sensations of thirst were lower (P < 0.05) in ORAL compared with IV and NF, likely because of oropharyngeal stimuli.

CONCLUSIONS

Despite a more rapid restoration of plasma volume, IV rehydration was not advantageous over ORAL rehydration in regards to physiological strain, heat tolerance, RPE, or thermal sensations.

Authors+Show Affiliations

U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760, USA. Robert.Kenefick@us.army.milNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Randomized Controlled Trial

Language

eng

PubMed ID

17146319

Citation

Kenefick, Robert W., et al. "Rapid IV Versus Oral Rehydration: Responses to Subsequent Exercise Heat Stress." Medicine and Science in Sports and Exercise, vol. 38, no. 12, 2006, pp. 2125-31.
Kenefick RW, O'Moore KM, Mahood NV, et al. Rapid IV versus oral rehydration: responses to subsequent exercise heat stress. Med Sci Sports Exerc. 2006;38(12):2125-31.
Kenefick, R. W., O'Moore, K. M., Mahood, N. V., & Castellani, J. W. (2006). Rapid IV versus oral rehydration: responses to subsequent exercise heat stress. Medicine and Science in Sports and Exercise, 38(12), 2125-31.
Kenefick RW, et al. Rapid IV Versus Oral Rehydration: Responses to Subsequent Exercise Heat Stress. Med Sci Sports Exerc. 2006;38(12):2125-31. PubMed PMID: 17146319.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Rapid IV versus oral rehydration: responses to subsequent exercise heat stress. AU - Kenefick,Robert W, AU - O'Moore,Kathleen M, AU - Mahood,Nicholas V, AU - Castellani,John W, PY - 2006/12/6/pubmed PY - 2007/1/31/medline PY - 2006/12/6/entrez SP - 2125 EP - 31 JF - Medicine and science in sports and exercise JO - Med Sci Sports Exerc VL - 38 IS - 12 N2 - PURPOSE: This study sought to determine the effect of rapid intravenous (IV) versus oral (ORAL) rehydration immediately after dehydration, on cardiovascular, thermoregulatory, and perceptual responses during subsequent exercise in the heat. METHODS: Eight males (21.4 +/- 0.7 yr; 176.2 +/- 1.6 cm; 75.2 +/- 3.7 kg; 63.7 +/- 3.6 mL.kg.min VO2max, 9.0 +/- 1.7% fat) participated in three randomized trials. Each trial consisted of a 75-min dehydration phase (36 degrees C; 42.5% rh, 47 +/- 0.9% VO2max) where subjects lost 1.7 L (IV and no-fluid (NF) trials) to 1.8 L of fluid (ORAL trial). In the heat, fluid lost was matched with 0.45% saline in 20 min by either IV or ORAL rehydration; no fluid was given in the NF trial. Subjects then performed a heat-tolerance test (HTT; 37.0 degrees C, 45% rh, treadmill speed of 2.4 m.s, 2.3% grade) for 75 min or until exhaustion (Tre of 39.5 degrees C). During the HTT, thermal and thirst sensations, RPE, rectal temperature (Tre), heart rate (HR), and mean weighted skin temperature (Tsk) were measured. RESULTS: Plasma volume in the IV treatment was greater (P < 0.05) after rehydration compared with ORAL and NF. However, during the HTT there were no overall differences (P > 0.05) in HR, Tre, Tsk, RPE, thermal sensations, or HTT time (ORAL, 71 +/- 8 min; IV, 73 +/- 5 min; NF, 39 +/- 29 min) between the ORAL and IV treatments. Sensations of thirst were lower (P < 0.05) in ORAL compared with IV and NF, likely because of oropharyngeal stimuli. CONCLUSIONS: Despite a more rapid restoration of plasma volume, IV rehydration was not advantageous over ORAL rehydration in regards to physiological strain, heat tolerance, RPE, or thermal sensations. SN - 0195-9131 UR - https://www.unboundmedicine.com/medline/citation/17146319/Rapid_IV_versus_oral_rehydration:_responses_to_subsequent_exercise_heat_stress_ L2 - http://dx.doi.org/10.1249/01.mss.0000235358.39555.80 DB - PRIME DP - Unbound Medicine ER -