Advances in Applied Physiology

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The Effects of Salt and Water Loading on Kidney Function in Healthy Undergraduates

Received: Oct. 08, 2019    Accepted: Nov. 06, 2019    Published: Nov. 17, 2019
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Abstract

Rutgers University juniors and seniors enrolled in Systems Physiology Laboratory (01:146:356) Spring, 2019. One-hundred forty-five students volunteered to test the effects of salt and water loading on kidney function. Students were investigated beginning at 8:40 a.m., 1:40 p.m., and 6:40 p.m. They were approximately evenly distributed between male and female genders and were of multiple cultural/ethnic backgrounds. Upon entering the laboratory baseline data were collected. Approximately half of the volunteers then consumed 200 mL of a 2.0% NaCl solution (n=77). The others directly consumed 1.0 L of tap water (n=68). Upon entering the laboratory baseline data were collected. The others directly consumed 1.0 L of tap water. Kidney function was monitored each 30 minutes for the next 90 minutes. Under baseline conditions, urine osmolality was elevated in all students (≥ 280 mOsm/kg) but was significantly (P<0.05) greater in the 8:40 a.m. group than in either of the p.m. groups. Urine specific gravity and sodium excretion were also elevated in the 8:40 a.m. group compared to the others. Urine flow rate was least in the 8:40 group and greatest in the 1:40 p.m. group. We conclude that in these students renal function was influenced by a diurnal pattern. We also conclude that without compelling incentives (e.g. financial, grade-influencing) it was virtually impossible to get students to comply with pre-experimental instructions (e.g. no salt-laden meals after 6:00 p.m. before the day of experimentation).

DOI 10.11648/j.aap.20190402.11
Published in Advances in Applied Physiology ( Volume 4, Issue 2, December 2019 )
Page(s) 11-18
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2024. Published by Science Publishing Group

Keywords

Dehydration, Salt Loading, Urine Osmolality, Water Balance, Water Loading, Sodium Excretion, Urine Flow

References
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[5] Luis-Lima S, Porrini E. An overview of errors and flaws of estimated GFR versus true GFR in patients with diabetes mellitus. Nephron. 136: 287-291, 2017.
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[10] Singh AT, Mc Causland FR. Osmolality and blood pressure stability during hemodialysis. Semin Dial. 30: 509-517, 2017.
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[19] Nakada T, Kwee IL. Fluid dynamics inside the brain barrier: current concept of interstitial flow, lymphatic flow, and cerebrospinal fluid circulation in the brain. Neuroscientist. 25: 155-166. 2019.
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  • APA Style

    Ehmann Peter J., Brush Christopher J., Bozzini Brittany, Dowden Robert A., Ogilvie Anna, et al. (2019). The Effects of Salt and Water Loading on Kidney Function in Healthy Undergraduates. Advances in Applied Physiology, 4(2), 11-18. https://doi.org/10.11648/j.aap.20190402.11

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    ACS Style

    Ehmann Peter J.; Brush Christopher J.; Bozzini Brittany; Dowden Robert A.; Ogilvie Anna, et al. The Effects of Salt and Water Loading on Kidney Function in Healthy Undergraduates. Adv. Appl. Physiol. 2019, 4(2), 11-18. doi: 10.11648/j.aap.20190402.11

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    AMA Style

    Ehmann Peter J., Brush Christopher J., Bozzini Brittany, Dowden Robert A., Ogilvie Anna, et al. The Effects of Salt and Water Loading on Kidney Function in Healthy Undergraduates. Adv Appl Physiol. 2019;4(2):11-18. doi: 10.11648/j.aap.20190402.11

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  • @article{10.11648/j.aap.20190402.11,
      author = {Ehmann Peter J. and Brush Christopher J. and Bozzini Brittany and Dowden Robert A. and Ogilvie Anna and Wisniewski Paul J. and Bernard Laura P. and Merrill Gary F.},
      title = {The Effects of Salt and Water Loading on Kidney Function in Healthy Undergraduates},
      journal = {Advances in Applied Physiology},
      volume = {4},
      number = {2},
      pages = {11-18},
      doi = {10.11648/j.aap.20190402.11},
      url = {https://doi.org/10.11648/j.aap.20190402.11},
      eprint = {https://download.sciencepg.com/pdf/10.11648.j.aap.20190402.11},
      abstract = {Rutgers University juniors and seniors enrolled in Systems Physiology Laboratory (01:146:356) Spring, 2019. One-hundred forty-five students volunteered to test the effects of salt and water loading on kidney function. Students were investigated beginning at 8:40 a.m., 1:40 p.m., and 6:40 p.m. They were approximately evenly distributed between male and female genders and were of multiple cultural/ethnic backgrounds. Upon entering the laboratory baseline data were collected. Approximately half of the volunteers then consumed 200 mL of a 2.0% NaCl solution (n=77). The others directly consumed 1.0 L of tap water (n=68). Upon entering the laboratory baseline data were collected. The others directly consumed 1.0 L of tap water. Kidney function was monitored each 30 minutes for the next 90 minutes. Under baseline conditions, urine osmolality was elevated in all students (≥ 280 mOsm/kg) but was significantly (P<0.05) greater in the 8:40 a.m. group than in either of the p.m. groups. Urine specific gravity and sodium excretion were also elevated in the 8:40 a.m. group compared to the others. Urine flow rate was least in the 8:40 group and greatest in the 1:40 p.m. group. We conclude that in these students renal function was influenced by a diurnal pattern. We also conclude that without compelling incentives (e.g. financial, grade-influencing) it was virtually impossible to get students to comply with pre-experimental instructions (e.g. no salt-laden meals after 6:00 p.m. before the day of experimentation).},
     year = {2019}
    }
    

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    AU  - Ehmann Peter J.
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    AU  - Bernard Laura P.
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    AB  - Rutgers University juniors and seniors enrolled in Systems Physiology Laboratory (01:146:356) Spring, 2019. One-hundred forty-five students volunteered to test the effects of salt and water loading on kidney function. Students were investigated beginning at 8:40 a.m., 1:40 p.m., and 6:40 p.m. They were approximately evenly distributed between male and female genders and were of multiple cultural/ethnic backgrounds. Upon entering the laboratory baseline data were collected. Approximately half of the volunteers then consumed 200 mL of a 2.0% NaCl solution (n=77). The others directly consumed 1.0 L of tap water (n=68). Upon entering the laboratory baseline data were collected. The others directly consumed 1.0 L of tap water. Kidney function was monitored each 30 minutes for the next 90 minutes. Under baseline conditions, urine osmolality was elevated in all students (≥ 280 mOsm/kg) but was significantly (P<0.05) greater in the 8:40 a.m. group than in either of the p.m. groups. Urine specific gravity and sodium excretion were also elevated in the 8:40 a.m. group compared to the others. Urine flow rate was least in the 8:40 group and greatest in the 1:40 p.m. group. We conclude that in these students renal function was influenced by a diurnal pattern. We also conclude that without compelling incentives (e.g. financial, grade-influencing) it was virtually impossible to get students to comply with pre-experimental instructions (e.g. no salt-laden meals after 6:00 p.m. before the day of experimentation).
    VL  - 4
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Author Information
  • Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, USA

  • Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, USA; Department of Psychology, Florida State University, Tallahassee, USA

  • Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, USA

  • Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, USA

  • Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, USA

  • Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, USA

  • Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, USA

  • Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, USA

  • Section