Dehydration, Rehydration, and Impact on Physiology

NCT07084675 | Recruiting

• 1 other identifier: IRB2025-288
• Study Type: interventional
• Target: 15
• Locations: 1 country
• Sites: 1

Brief Summary

Our goal is to determine whether hydration status influences inflammation, and overall physiological performance in adults aged 45-65. Aim 1: The effects of 4-day mild dehydration followed by 4-day rehydration (defined as approximately 2-3% body mass loss) on H2O2, upstream inflammatory signal (NFkB), mitochondrial fragmentation, and autophagy in circulating PBMCs. Aim 2: The effects of 4-day mild dehydration followed by 4-day rehydration (defined as approximately 2-3% body mass loss) on fasting glucose, sleep performance, and strength performance. Participant will: complete a 4-day hydration protocol, followed by a 4-day dehydration protocol, and then a 4-day rehydration protocol. attend five laboratory visits for testing: Day 1: Informed consent and familiarization Day 2: Pre-hydration testing (before the 4-day hydration protocol) Day 3: Pre-dehydration testing (before the dehyration protocol) Day 4: Post-dehydration testing (after the dehydration protocol) Day 5: Post-rehydration testing (after the rehydration protocol)

Conditions

Aging

Keywords

rehydration; hypohydration

Outcome Measures

Primary Outcomes (15)

• Fasting blood glucose (mg/dL)

  Fasting blood glucose will be measured via fingerstick at each testing visit. Values will be used to examine changes in glucose regulation in response to hydration status across the HDR Protocol phases.

  Day 2 (Pre-hydration testing), Day 3 (Pre-dehydration testing), Day 4 (Post-dehydration testing), Day 5 (Post-rehydration testing)

• Total body water (L)

  Bioelectrical impedance spectroscopy (BIS) will be used to assess changes in total body water, BIS measurements will be collected at each testing visit to evaluate fluid shifts.

  Day 2 (Pre-hydration testing), Day 3 (Pre-dehydration testing), Day 4 (Post-dehydration testing), Day 5 (Post-rehydration testing)

• Intracellular water (L)

  Description: Bioelectrical impedance spectroscopy (BIS) will be used to assess changes in intracellular water across hydration phases. BIS measurements will be collected at each testing visit to evaluate fluid shifts.

  Time Frame: Day 2 (Pre-hydration testing), Day 3 (Pre-dehydration testing), Day 4 (Post-dehydration testing), Day 5 (Post-rehydration testing)

• Extracellular water (L)

  Description: Bioelectrical impedance spectroscopy (BIS) will be used to assess changes in extracellular water across hydration phases. BIS measurements will be collected at each testing visit to evaluate fluid shifts.

  Time Frame: Day 2 (Pre-hydration testing), Day 3 (Pre-dehydration testing), Day 4 (Post-dehydration testing), Day 5 (Post-rehydration testing)

• Hand grip strength (kg)

  Handgrip strength will be measured using a handheld dynamometer at four time points during the HDR Protocol. Measurements will be used to assess the impact of hydration status on upper body muscular strength.

  Day 2 (Pre-hydration testing), Day 3 (Pre-dehydration testing), Day 4 (Post-dehydration testing), Day 5 (Post-rehydration testing)

• Isometric leg pull strength (kg)

  Isometric lower body strength will be evaluated using a standardized leg pull test at four timepoints during the HDR Protocol. Results will be used to determine the effect of hydration status on lower body muscular strength.

  Day 2 (Pre-hydration testing), Day 3 (Pre-dehydration testing), Day 4 (Post-dehydration testing), Day 5 (Post-rehydration testing)

• Total sleep time (hrs)

  Total sleep time will be continuously monitored throughout the HDR Protocol using a wearable device.

  through study completion, 18 days

• Sleep efficiency (%)

  Sleep efficiency will be continuously monitored throughout the HDR Protocol using a wearable device.

  through study completion, 18 days

• Number of awakenings (count)

  Number of awakenings will be continuously monitored throughout the HDR Protocol using a wearable device.

  through study completion, 18 days

• PBMC H2O2 ( µg/mL)

  Peripheral blood mononuclear cells (PBMCs) will be isolated from whole blood samples collected at four time points during the HDR Protocol. H2O2 will be assessed.

  Day 2 (Pre-hydration testing), Day 3 (Pre-dehydration testing), Day 4 (Post-dehydration testing), Day 5 (Post-rehydration testing)

• DRP1 (Arbitrary Units)

  Peripheral blood mononuclear cells (PBMCs) will be isolated from whole blood samples collected at four time points during the HDR Protocol. Fission expression (DRP1).

  Day 2 (Pre-hydration testing), Day 3 (Pre-dehydration testing), Day 4 (Post-dehydration testing), Day 5 (Post-rehydration testing)

• MFN (Arbitrary Units)

  Peripheral blood mononuclear cells (PBMCs) will be isolated from whole blood samples collected at four time points during the HDR Protocol. Mitochondrial fusion expression (MFN) will be assessed.

  Day 2 (Pre-hydration testing), Day 3 (Pre-dehydration testing), Day 4 (Post-dehydration testing), Day 5 (Post-rehydration testing)

• PINK1 (Arbitrary Units)

  Peripheral blood mononuclear cells (PBMCs) will be isolated from whole blood samples collected at four time points during the HDR Protocol. Mitophagy marker (PINK1) will be assessed.

  Day 2 (Pre-hydration testing), Day 3 (Pre-dehydration testing), Day 4 (Post-dehydration testing), Day 5 (Post-rehydration testing)

• Parkin (Arbitrary Units)

  Peripheral blood mononuclear cells (PBMCs) will be isolated from whole blood samples collected at four time points during the HDR Protocol. Mitophagy marker (Parkin) will be assessed.

  Day 2 (Pre-hydration testing), Day 3 (Pre-dehydration testing), Day 4 (Post-dehydration testing), Day 5 (Post-rehydration testing)

• Malondialdehyde (nmol/mg)

  Peripheral blood mononuclear cells (PBMCs) will be isolated from whole blood samples collected at four time points during the HDR Protocol. Lipid peroxidation will be assessed by measuring malondialdehyde concentrations.

  Day 2 (Pre-hydration testing), Day 3 (Pre-dehydration testing), Day 4 (Post-dehydration testing), Day 5 (Post-rehydration testing)

Secondary Outcomes (3)

• Change in hydration status via urine specific gravity (USG)

  Day 2 (Pre-hydration testing), Day 3 (Pre-dehydration testing), Day 4 (Post-dehydration testing), Day 5 (Post-rehydration testing)

• Total lean mass (g)

  Day 2 (Pre-hydration testing), Day 3 (Pre-dehydration testing), Day 4 (Post-dehydration testing), Day 5 (Post-rehydration testing)

• Total fat mass (g)

  Day 2 (Pre-hydration testing), Day 3 (Pre-dehydration testing), Day 4 (Post-dehydration testing), Day 5 (Post-rehydration testing)

Study Arms (1)

Hydration-Dehydration-Rehydration (HDR) Protocol Arm

EXPERIMENTAL

Participants in this arm complete the HDR Protocol over 12 days and attend five lab visits.

Behavioral: Hydration-Dehydration-Rehydration Protocol (HDR)

Interventions

Hydration-Dehydration-Rehydration Protocol (HDR) BEHAVIORAL

The HDR Protocol is a 12-day, sequential fluid manipulation intervention designed to assess the physiological effects of controlled changes in hydration status. The protocol consists of three consecutive 4-day phases: Hydration Phase (Days 1-4): Participants follow a standardized fluid intake protocol designed to promote and maintain a euhydrated state. Hydration status is monitored using objective measures such as urine specific gravity and body mass. Dehydration Phase (Days 5-8): Participants adhere to a fluid-restriction regimen to induce a hypohydrated state. The level of dehydration is verified through the same hydration status measures to ensure consistent and safe hypohydration. Rehydration Phase (Days 9-12): Participants resume the standardized fluid intake protocol used during the Hydration Phase to restore euhydration. Rehydration effectiveness is confirmed through repeated hydration assessments.

Hydration-Dehydration-Rehydration (HDR) Protocol Arm

Eligibility Criteria

• Age: 45 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Apparently Healthy
• BMI \< 30 kg/m2
• Body weight is at least 110 lbs

You may not qualify if:

• Currently pregnant
• Have Type 1 Diabetes or Type 2 Diabetes
• Have chronic kidney disease or a history of kidney stones
• Have hypertension
• Take medications that can cause fluid retention, such as corticosteroids, chronic use of Nonsteroidal Anti-inflammatory Drugs (NSAIDs), Hormonal Therapies (e.g., estrogen, androgens or anabolic steroids), Antihypertensives, Psychiatric Medications (e.g., Lithium), Vasodilators
• Take medications that reduce fluid retention: diuretics, and RAAS Inhibitors (e.g., ACE inhibitors and ARBs)

Sponsors & Collaborators

• Texas Tech University: lead

Study Sites (1)

Texas Tech University

Lubbock, Texas, 79409, United States

RECRUITING

Central Study Contacts

Hui Ying Luk, Ph.D.

CONTACT

806-834-0827; huiying.luk@ttu.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Study Record Dates

• First Submitted: July 3, 2025
• First Posted: July 24, 2025
• Study Start: July 15, 2025
• Primary Completion: December 1, 2025
• Study Completion (Estimated): December 1, 2026
• Last Updated: September 17, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will share

Locations

US (1)