An interventional study of Modifying daily total fluid intake in Hydration Status, Psychosocial Stress and Fluid Intake, sponsored by Liverpool John Moores University. Recruiting at 1 site in United Kingdom. Open to participants aged 18 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-27.
Sponsored by Liverpool John Moores University · Not applicable, Interventional, and Basic science
Over half of the adult population in Europe, Asia and Latin America fail to meet adequate water intake guidelines as advised by the European Food Safety Authority (EFSA; 2.5 and 2 litres/day for men and women, respectively coming from both food and drinks). Increasing epidemiological evidence suggests that chronic low fluid intake may be associated with an increased risk of cardiovascular, metabolic, and renal diseases. The association between chronic low fluid intake and increased morbidity risk may be underpinned by elevations in key water-regulating hormones, such as arginine vasopressin (AVP) and its surrogate copeptin, which influence glucose regulation and renal function. For example, AVP stimulates the hypothalamic-pituitary adrenal (HPA) axis to release the stress hormone cortisol with potentially far-reaching effects on metabolism, immunity and inflammation. Prospective cohort studies have demonstrated that exaggerated cortisol responses to acute stress are associated with poor health outcomes.
A recent cross-sectional study (NCT05491122) from our group found that individuals with a low habitual fluid intake experienced greater cortisol reactivity to acute stress than those with a high habitual intake. The findings of this study may provide a potential explanation for why poor hydration and low fluid intake have negative effects on long-term health. We now aim to explore whether altering fluid intake influences cortisol reactivity to acute stress.
Liverpool John Moores University is the lead sponsor of 75 studies on the registry; 13 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Individuals who…
Exclusion Criteria:
Individuals who…
Health screening
Individuals who…
Total fluid intake screening
Individuals who…
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
7 consecutive days where participants will drink fluids as they do normally do.
7 consecutive days where the participants will be randomly assigned to either the habitual or intervention condition. * Habitual: maintain their usual daily total fluid intake. * Intervention: habitual low daily TFI will be prescribed a total fluid intake of 3.5 L/day for men and 3.3 L/day for women. Habitual high daily total fluid intake will be prescribed a total fluid intake of 1.3 L/day for both men and women. On day 8, participants will perform a psychosocial stress test. Participants will be instructed to maintain their usual intake of other beverages i.e., tea/coffee to achieve their target total fluid intake.
Behavioral: Modifying daily total fluid intake
7-day intervention where the intake of drinking water will either be maintained at habitual level, increased (if habitually low) or decreased (if habitually high). The TFI prescriptions during the intervention are derived from the mean TFI of habitually low and habitually high drinkers from a sex, age and country matched population. Specifically, habitually low drinkers will be permitted a TFI of 3.5 L/day for men and 3.3 L/day for women and habitually high drinkers will be permitted a TFI of 1.3 L/day. Participants will be instructed to maintain their usual intake of other beverages i.e., tea/coffee to achieve their target TFI.
Salivary cortisol reactivity to acute psychosocial stress
Changes in the concentration of salivary free cortisol throughout the psychosocial stress test. Cortisol will be measured in stimulated saliva samples and analysed by ELISA. Delta changes (increase/decrease) in cortisol response will also be calculated.
Time frame: Assessed during the main trial (day 8 of the intervention period). Saliva samples will be taken pre (-30 and -5 minutes) and post (+0, +10, +20, +30, +45 and +60 minutes) stress test.
Plasma copeptin
Plasma copeptin will be analysed by ELISA and compared cross-sectionally between intervention conditions.
Time frame: Copeptin will be assessed using a single blood sample taken on the morning of the main trial (day 8 of intervention period).
Urine osmolality (UOsm)
The concentration of osmotic solutes present in the urine, measured using a freezing point depression osmometer.
Time frame: Late-afternoon urine samples will be collected on days 6 and 7 of the verification and intervention periods. Spot urine samples will be collected on the morning and afternoon visits of the main trial (day 8 of the intervention period).
Urine colour
Urine colour, a common marker used for assessing hydration status, will be assessed using a urine colour chart that has been developed to assess urine concentration in healthy humans.
Time frame: Late-afternoon urine samples will be collected on days 6 and 7 of the verification and intervention periods. Spot urine samples will be collected on the morning and afternoon visits of the main trial (day 8 of the intervention period).
Plasma osmolality
A marker of intracellular osmolality, measured using a freezing point depression osmometer. Plasma will be derived from venous blood.
Time frame: A venous blood sample will be taken on the morning of the main trial (day 8 of the intervention period).
Sleep duration
Total sleep time (minutes) will be measured using accelerometery-based movement data recorded using a wrist-worn actigraph.
Time frame: Verification period: an actigraph will be worn continuously from day 5 until the end of the verification period. Intervention period: an actigraph will be worn continuously from day 5 until the stress test on day 8.
Sleep efficiency
Sleep efficiency will be calculated using the following equation: (total sleep time/total time in bed) \* 100.
Time frame: Verification period: an actigraph will be worn continuously from day 5 until the end of the verification period. Intervention period: an actigraph will be worn continuously from day 5 until the stress test on day 8.
State anxiety (STAI-S) response to acute psychosocial stress
State anxiety will be assessed throughout the acute stress test using the state aspect (form Y1) of the State-Trait Anxiety Inventory (STAI-S).
Time frame: Assed during the main trial (day 8 of the intervention period). The STAI-S will be administered pre (-30 and -5 minutes) and post (+0, +10, +20, +30, +45 and +60 minutes) stress test.
Subjective stress response to acute psychosocial stress
Subjective stress will be assessed using the Subjective Stress Scale, a 0-9 Likert scale where participants rate how stressed they feel right now (0 = no subjective stress experience, 4 = moderate subjective stress experience, 9 = extreme subjective stress experience).
Time frame: Assessed during the main trial (day 8 of the intervention period). The Subjective Stress Scale will be administered pre (-30 and -5 minutes) and post (+0, +10, +20, +30, +45 and +60 minutes) post stress test.
Trait anxiety (STAI-T) profiling
Trait anxiety will be measured using the trait aspect (form Y2) of the State-Trait Anxiety Inventory (STAI-T). The STAI-T will be used as a part of participant profiling and demographic assessment.
Time frame: The STAI-T will be administered once, immediately after enrolling.
Sleep quality (PSQI) profiling
The Pittsburgh Sleep Quality Index (PSQI) will be used to profile participants' sleep quality in the month prior to the study.
Time frame: The PSQI will be administered once, immediately after enrolling.
Perceived stress (PSS) profiling
The Perceived Stress Scale (PSS) will be used to profile participants' perceived stress in the month prior to the study.
Time frame: The PSS will be administered once, immediately after enrolling.
Perceived stress during the verification and intervention periods
A modified version of the PSS referring to the "last week" instead of "last month" (PSS-week) will be used to assess perceived stress during the verification and intervention periods.
Time frame: The PSS-week will be administered on the familiarisation visit (between verification and intervention periods) and the morning of the main trial (day 8 of the intervention period).
Sleep quality during the verification and intervention periods
Participants will rate their sleep quality for the previous night on scale of 1 to 4. 1 = Very Poor, 2 = Poor, 3 = Good, 4 = Very good. This question will be completed as part of a larger daily study diary.
Time frame: Up to 2 weeks. Assessed daily from day 1-7 of the verification period and day 1-7 of the intervention period.
Mood during the verification and intervention periods
The Brunel Mood Scale (BRUMS) will be used to assess mood over the last week, and will be used to characterise mood during the verification and intervention periods.
Time frame: The BRUMS will be administered on the familiarisation visit (between verification and intervention periods) and morning of the main trial (day 8 of the intervention period).
Nocturia during the verification and intervention periods
The number of night time voids will be self-reported, followed by a question assessing how much this bothered the participant on a scale of 1 (Not at all) to 10 (A great deal). These will be completed as part of a larger daily study diary.
Time frame: Up to 2 weeks. Assessed daily from day 1-7 of the verification period and day 1-7 of the intervention period.
Heart rate during acute psychosocial stress
Heart rate will be measured using a telemetric chest strap.
Time frame: Continuously measured during the stress test on the main trial (day 8 of the intervention period). Heart rate measurement will start at 30 minutes pre-stress test and continue until 60 minutes post-stress test.
Thirst sensation during the verification and intervention periods
A subjective rating of thirst will be recorded on a scale from 0 (not thirsty at all) to 7 (very, very thirsty) and a visual analogue scale ranging from "not thirsty" to "very thirsty". The ratings will be completed in the evening (approx. 30 min before bed) as part of a larger daily study diary.
Time frame: Every evening during days 1-7 of the verification and intervention periods.
Daily total fluid intake (TFI) during the verification and intervention periods
TFI will be recorded as part of a larger daily study diary. For this study, TFI refers to all drinks consumed e.g., water, tea/coffee, milk, juice, soft drinks and alcohol. Each drink will be recorded as close to the time of consumption as possible.
Time frame: Up to 15 days. Daily from day 1 to 7 of the verification period and day 1 to 8 of the intervention period.
Skin issue profiling
The SkinCARE Questionnaire will be used to profile participants for self-reported skin issues experienced in the previous 4 weeks.
Time frame: The SkinCARE Questionnaire will be administered once, during the familiarisation visit (between verification and intervention periods).
Physical activity
Actigraphy data analysed to estimate physical activity
Time frame: Verification period: an actigraph will be worn continuously from day 5 until the end of the verification period. Intervention period: an actigraph will be worn continuously from day 5 until the stress test on day 8
Plan to share: Yes — Only IPD used in the results publication(s).
Time frame: Beginning 3 months after publication with no end date.
Started Jun 2026 (actual). Primary completion is estimated for Sep 2027, 14 months after the start.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Liverpool John Moores University