Fluid Balance, Kidney Function, and Acute Kidney Injury Risk in Healthy Men and Women During Simulated Work-related Heat Stress.

Details

• Alternative Title:
  Journal of Applied Physiology (Bethesda, Md. : 1985), 2026, v. 140, no. 5: Fluid Balance, Kidney Function, and Acute Kidney Injury Risk in Healthy Men and Women During Simulated Work-related Heat Stress.
• Journal Article:
  Journal of Applied Physiology (Bethesda, Md. : 1985)
• Personal Author:
  Freemas, Jessica A. ; Goss, Curtis S. ; Ables, Riley ; Baker, Tyler B. ; Bruinvels, Georgie ; Mündel, Toby ; Martin, Bruce J ; Carter, Stephen J. ; Chapman, Robert F. ; Khandpekar, Omkar M. ; Zoh, Roger S. ; Schlader, Zachary J.
• Description:
  We tested the hypothesis that men are at greater risk of dehydration during simulated work-related heat stress (WrHS) compared with women independent of menstrual cycle phase. Twelve eumenorrheic women completed a WrHS simulation during the early follicular (EF), late follicular (LF), and midluteal (ML) phase of their menstrual cycle and 12 men completed one WrHS simulation. The WrHS simulation involved a 4-h exposure to 33.8 ± 0.8°C, 54 ± 1% relative humidity, where participants walked on a treadmill for 30 min per hour at a rate of metabolic heat production of 5.2 ± 0.7 W/kg (199 ± 28 W/m
  
  ). Participants drank a cool noncaloric sport drink ad libitum. Percent changes in nude body weight from pre- to post-WrHS did not differ between men (-0.5 ± 0.5%) and women (EF: -0.5 ± 0.9%; LF: -0.3 ± 0.9%; ML: -0.3 ± 0.7%) during any phase of the menstrual cycle (
  
  ≥ 0.4694). Relative fluid intake was higher in women during LF 43 ± 18 mL/kg lean body mass (LBM);
  
  = 0.0148 and ML (43 ± 16 mL/kg LBM;
  
  = 0.0048), but not EF (36 ± 21 mL/kg LBM;
  
  = 0.1792) compared with men (24 ± 5 mL/kg LBM). Relative urine output was higher in women (20 ± 12 mL/kg LBM) compared with men (8 ± 4 mL/kg LBM) across menstrual cycle phases (
  
  ≤ 0.0367). Relative total sweat loss did not differ between men 700 ± 160 mL/m
  
  body surface area (BSA) and women (675 ± 254 mL/m
  
  BSA) during any phase of the menstrual cycle (
  
  ≥ 0.8458). Although the way it was achieved differed, when cool fluids are available, fluid balance is similarly achieved in men and women independent of the menstrual cycle, suggesting that the risk of dehydration during WrHS is not modified by biological sex.
  
  Although men are often thought to be at greater risk of dehydration during work-related heat stress due to lower fluid intake, the impact of biological sex on fluid balance remains unclear. This study shows that when cool fluids are available, men and women maintain similar fluid balance regardless of menstrual cycle phase, suggesting that sex does not influence dehydration risk during simulated work-related heat stress.
• Content Notes:
  Author manuscript
• Subjects:
  • Humans
  • Female
  • Male
  • Water-Electrolyte Balance
  • Heat Stress Disorders
  • Adult
  • Dehydration
  • Menstrual Cycle
  • Young Adult
  • Acute Kidney Injury
  More +
• Keywords:
  • ad libitum drinking
  • exercise
  • kidney function
  • fluid regulation
  • sex hormones
• Source:
  Journal of Applied Physiology (Bethesda, Md. : 1985), 2026, v. 140, no. 5
• DOI:
  https://doi.org/10.1152/japplphysiol.00822.2025
• ISSN:
  8750-7587 ; 1522-1601
• Pubmed ID:
  41914660
• Pubmed Central ID:
  PMC13110122
• Document Type:
  Text
• Funding:
  R01 OH011528/OH/NIOSH CDC HHSUnited States/ ; Carl V. Gisolfi Memorial Fund/American College of Sports Medicine Foundation/ ; R01OH011528/HHS ; Centers for Disease Control and Prevention (CDC)/ ; Indiana University Graduate School/
• Genre:
  Journal Article
• Pages in Document:
  1187-1202 (34 pdf pages)
• Volume:
  140
• Issue:
  5
• Download URL:
  https://stacks.cdc.gov/view/cdc/260715/cdc_260715_DS1.pdf
• File Type:
  [PDF - 2.26 MB]
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha-512:8bb6a81c5887fe1ae91357b0f7374fb68accf05203f0c5b97f39183bbd0fa62426fb6466f24b8136fb8eca7a6a59dc784f17adb2cfbc77a262fd25385c3960d7