Tags

Type your tag names separated by a space and hit enter

Hydration and vascular fluid shifts during exercise in the heat.

Abstract

This study examined the effects of hypohydration on plasma volume and red cell volume during rest in a comfortable (20 degrees C, 40% relative humidity) and exercise in a hot-dry (49 degrees C, 20% relative humidity) environment. A group of six male and six female volunteers [matched for maximal O2 uptake (VO2 max)] completed two test sessions following a 10-day heat acclimation program. One test session was completed when subjects were euhydrated and the other when subjects were hypohydrated (-5% from base-line body wt). The test sessions consisted of rest for 30 min in a 20 degrees C antechamber, followed by two 25-min bouts of treadmill walking (approximately 30% of VO2 max) in the heat, interspersed by 10 min of rest. No significant differences were found between the genders for the examined variables. At rest, hypohydration elicited a 5% decrease in plasma volume with less than 1% change in red cell volume. During exercise, plasma volume increased by 4% when subjects were euhydrated and decreased by 4% when subjects were hypohydrated. These percent changes in plasma volume values were significantly (P less than 0.01) different between the euhydration and hypohydration tests. Although red cell volume remained fairly constant during the euhydration test, these values were significantly (P less than 0.01) lower when hypohydrated during exercise. We conclude that hydration level alters vascular fluid shifts during exercise in a hot environment; hemodilution occurs when euhydrated and hemoconcentration when hypohydrated during light intensity exercise for this group of fit men and women.

Authors

No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

6693339

Citation

Sawka, M N., et al. "Hydration and Vascular Fluid Shifts During Exercise in the Heat." Journal of Applied Physiology: Respiratory, Environmental and Exercise Physiology, vol. 56, no. 1, 1984, pp. 91-6.
Sawka MN, Francesconi RP, Pimental NA, et al. Hydration and vascular fluid shifts during exercise in the heat. J Appl Physiol Respir Environ Exerc Physiol. 1984;56(1):91-6.
Sawka, M. N., Francesconi, R. P., Pimental, N. A., & Pandolf, K. B. (1984). Hydration and vascular fluid shifts during exercise in the heat. Journal of Applied Physiology: Respiratory, Environmental and Exercise Physiology, 56(1), 91-6.
Sawka MN, et al. Hydration and Vascular Fluid Shifts During Exercise in the Heat. J Appl Physiol Respir Environ Exerc Physiol. 1984;56(1):91-6. PubMed PMID: 6693339.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Hydration and vascular fluid shifts during exercise in the heat. AU - Sawka,M N, AU - Francesconi,R P, AU - Pimental,N A, AU - Pandolf,K B, PY - 1984/1/1/pubmed PY - 1984/1/1/medline PY - 1984/1/1/entrez SP - 91 EP - 6 JF - Journal of applied physiology: respiratory, environmental and exercise physiology JO - J Appl Physiol Respir Environ Exerc Physiol VL - 56 IS - 1 N2 - This study examined the effects of hypohydration on plasma volume and red cell volume during rest in a comfortable (20 degrees C, 40% relative humidity) and exercise in a hot-dry (49 degrees C, 20% relative humidity) environment. A group of six male and six female volunteers [matched for maximal O2 uptake (VO2 max)] completed two test sessions following a 10-day heat acclimation program. One test session was completed when subjects were euhydrated and the other when subjects were hypohydrated (-5% from base-line body wt). The test sessions consisted of rest for 30 min in a 20 degrees C antechamber, followed by two 25-min bouts of treadmill walking (approximately 30% of VO2 max) in the heat, interspersed by 10 min of rest. No significant differences were found between the genders for the examined variables. At rest, hypohydration elicited a 5% decrease in plasma volume with less than 1% change in red cell volume. During exercise, plasma volume increased by 4% when subjects were euhydrated and decreased by 4% when subjects were hypohydrated. These percent changes in plasma volume values were significantly (P less than 0.01) different between the euhydration and hypohydration tests. Although red cell volume remained fairly constant during the euhydration test, these values were significantly (P less than 0.01) lower when hypohydrated during exercise. We conclude that hydration level alters vascular fluid shifts during exercise in a hot environment; hemodilution occurs when euhydrated and hemoconcentration when hypohydrated during light intensity exercise for this group of fit men and women. SN - 0161-7567 UR - https://www.unboundmedicine.com/medline/citation/6693339/Hydration_and_vascular_fluid_shifts_during_exercise_in_the_heat_ DB - PRIME DP - Unbound Medicine ER -