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Effect of the Volume of Fluid Ingested on Urine Concentrating Ability During Prolonged Heavy Exercise in a Hot Environment.
- Source :
-
Journal of Sports Science & Medicine . 2013, Vol. 12 Issue 1, p197-204. 8p. - Publication Year :
- 2013
-
Abstract
- This study examined the effect of the volume of fluid ingested on urine concentrating ability during prolonged heavy exercise in a hot environment at low levels of dehydration. Seven healthy males performed 105 min of intermittent cycle exercise at 70% maximum oxygen uptake (32°C, 60% relative humidity) while receiving no fluid ingestion (NF), voluntary fluid ingestion (VF), partial fluid ingestion equivalent to one-half of body mass loss (PF), and full fluid ingestion equivalent to body mass loss (FF). Fluid (5°C, 3.4% carbohydrate, 10.5 mmol.L-1 sodium) was ingested just before commencing exercise and at 15, 33, 51, 69, and 87 min of exercise, and the total amount of fluid ingested in PF and FF was divided into six equal volumes. During exercise, body mass loss was 2.2 ± 0.2, 1.1 ± 0.5, 1.1 ± 0.2, and 0.1 ± 0.2% in NF, VF, PF, and FF, respectively, whereas total sweat loss was about 2% of body mass in each trial. Subjects in VF ingested 719 ± 240 ml of fluid during exercise; the volume of fluid ingested was 1.1 ± 0.4% of body mass. Creatinine clearance was significantly higher and free water clearance was significantly lower in FF than in NF during exercise. Urine flow rate during exercise decreased significantly in NF. There were significant decreases in creatinine and osmolar clearance and was a significant increase in free water clearance during exercise in NF and VF. Creatinine clearance decreased significantly and free water clearance increased significantly during exercise in PF. There was no statistical change in urinary indices of renal function during exercise in FF. The findings suggest that full fluid ingestion equivalent to body mass loss has attenuated the decline in urine concentrating ability during prolonged heavy exercise in a hot environment at low levels of dehydration. [ABSTRACT FROM AUTHOR]
- Subjects :
- *URINE
*ANALYSIS of variance
*ANTHROPOMETRY
*REGULATION of body fluids
*MEDICAL thermometry
*CARDIOPULMONARY system
*CLINICAL trials
*CREATININE
*CROSSOVER trials
*CYCLING
*DEHYDRATION
*DRINKING (Physiology)
*EXERCISE physiology
*EXERCISE tests
*GLOMERULAR filtration rate
*HEART rate monitoring
*HEAT
*HEMATOCRIT
*HEMOGLOBINS
*KIDNEY function tests
*MATHEMATICS
*NUTRITIONAL assessment
*PERSPIRATION
*STATISTICAL sampling
*STATISTICS
*DATA analysis
*STATISTICAL significance
*EFFECT sizes (Statistics)
*RANDOMIZED controlled trials
*REPEATED measures design
*OXYGEN consumption
*ERGOMETRY
*OSMOLAR concentration
*EXERCISE intensity
*DESCRIPTIVE statistics
*PHYSIOLOGY
Subjects
Details
- Language :
- English
- ISSN :
- 13032968
- Volume :
- 12
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Journal of Sports Science & Medicine
- Publication Type :
- Academic Journal
- Accession number :
- 91530293