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No effect of 5% hypohydration on running economy of competitive runners at 23 degrees C.
Med Sci Sports Exerc. 2006 Oct; 38(10):1762-9.MS

Abstract

PURPOSE

Although running economy (RE) is recognized as an integral component of successful endurance performance and is affected by numerous factors, little is known about the influence of body water loss on RE. This investigation examined the effects of hypohydration (HY) on RE and associated physiological responses.

METHODS

Ten highly trained collegiate distance runners (mean +/- SD; age, 20 +/- 3 yr; height, 178.5 +/- 6.3 cm; body mass, 66.7 +/- 5.4 kg; VO2max, 66.5 +/- 4.1 mL x kg(-1) x min(-1)) participated in four experiments on separate days, twice in a euhydrated (EU) and twice in a HY state (-5.5 and -5.7% body mass loss achieved during 24 h). At each hydration level, subjects performed one 10-min treadmill run per day (23 degrees C environment), at either 70% VO2max (EU 70% or HY 70%) or 85% VO2max (EU 85% or HY 85%) in a randomized, repeated-measures design. Cardiopulmonary, metabolic, thermal, hormonal, and perceptual variables were measured.

RESULTS

No between-treatment differences existed for RE (EU 70%, 46.3 +/- 3.2; HY 70%, 47.2 +/- 3.8; EU 85%, 58.6 +/- 2.8; HY 85%, 58.9 +/- 4.1 mL x kg(-1) x min(-1)), postexercise plasma lactate concentration (EU 70%, 1.9 +/- 0.6; HY 70%, 1.8 +/- 0.6; EU 85%, 6.5 +/- 3.5; HY 85%, 6.4 +/- 3.5 mmol x L(-1)), or rating of perceived exertion. HY resulted in a greater (P < 0.05 to 0.001) heart rate (HR), rectal temperature, and plasma norepinephrine concentration (NE), concurrent with reduced cardiac output, stroke volume, and respiratory exchange ratio.

CONCLUSION

HY did not alter the RE or lactate accumulation of endurance athletes during 10 min of exercise at 70 and 85% VO2max. These findings indicate that HY had no effect on RE, but that it increased physiological strain in a 23 degrees C environment.

Authors+Show Affiliations

Human Performance Laboratory, Department of Kinesiology, University of Connecticut, Storrs, CT 06269-1110, USA. lawrence.armstrong@uconn.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Clinical Trial
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

17019298

Citation

Armstrong, Lawrence E., et al. "No Effect of 5% Hypohydration On Running Economy of Competitive Runners at 23 Degrees C." Medicine and Science in Sports and Exercise, vol. 38, no. 10, 2006, pp. 1762-9.
Armstrong LE, Whittlesey MJ, Casa DJ, et al. No effect of 5% hypohydration on running economy of competitive runners at 23 degrees C. Med Sci Sports Exerc. 2006;38(10):1762-9.
Armstrong, L. E., Whittlesey, M. J., Casa, D. J., Elliott, T. A., Kavouras, S. A., Keith, N. R., & Maresh, C. M. (2006). No effect of 5% hypohydration on running economy of competitive runners at 23 degrees C. Medicine and Science in Sports and Exercise, 38(10), 1762-9.
Armstrong LE, et al. No Effect of 5% Hypohydration On Running Economy of Competitive Runners at 23 Degrees C. Med Sci Sports Exerc. 2006;38(10):1762-9. PubMed PMID: 17019298.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - No effect of 5% hypohydration on running economy of competitive runners at 23 degrees C. AU - Armstrong,Lawrence E, AU - Whittlesey,Michael J, AU - Casa,Douglas J, AU - Elliott,Tabatha A, AU - Kavouras,Stavros A, AU - Keith,Nicole R, AU - Maresh,Carl M, PY - 2006/10/5/pubmed PY - 2006/12/12/medline PY - 2006/10/5/entrez SP - 1762 EP - 9 JF - Medicine and science in sports and exercise JO - Med Sci Sports Exerc VL - 38 IS - 10 N2 - PURPOSE: Although running economy (RE) is recognized as an integral component of successful endurance performance and is affected by numerous factors, little is known about the influence of body water loss on RE. This investigation examined the effects of hypohydration (HY) on RE and associated physiological responses. METHODS: Ten highly trained collegiate distance runners (mean +/- SD; age, 20 +/- 3 yr; height, 178.5 +/- 6.3 cm; body mass, 66.7 +/- 5.4 kg; VO2max, 66.5 +/- 4.1 mL x kg(-1) x min(-1)) participated in four experiments on separate days, twice in a euhydrated (EU) and twice in a HY state (-5.5 and -5.7% body mass loss achieved during 24 h). At each hydration level, subjects performed one 10-min treadmill run per day (23 degrees C environment), at either 70% VO2max (EU 70% or HY 70%) or 85% VO2max (EU 85% or HY 85%) in a randomized, repeated-measures design. Cardiopulmonary, metabolic, thermal, hormonal, and perceptual variables were measured. RESULTS: No between-treatment differences existed for RE (EU 70%, 46.3 +/- 3.2; HY 70%, 47.2 +/- 3.8; EU 85%, 58.6 +/- 2.8; HY 85%, 58.9 +/- 4.1 mL x kg(-1) x min(-1)), postexercise plasma lactate concentration (EU 70%, 1.9 +/- 0.6; HY 70%, 1.8 +/- 0.6; EU 85%, 6.5 +/- 3.5; HY 85%, 6.4 +/- 3.5 mmol x L(-1)), or rating of perceived exertion. HY resulted in a greater (P < 0.05 to 0.001) heart rate (HR), rectal temperature, and plasma norepinephrine concentration (NE), concurrent with reduced cardiac output, stroke volume, and respiratory exchange ratio. CONCLUSION: HY did not alter the RE or lactate accumulation of endurance athletes during 10 min of exercise at 70 and 85% VO2max. These findings indicate that HY had no effect on RE, but that it increased physiological strain in a 23 degrees C environment. SN - 0195-9131 UR - https://www.unboundmedicine.com/medline/citation/17019298/No_effect_of_5_hypohydration_on_running_economy_of_competitive_runners_at_23_degrees_C_ L2 - https://doi.org/10.1249/01.mss.0000230123.68394.ff DB - PRIME DP - Unbound Medicine ER -