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HealthyNCT05491122

The Influence of Fluid Intake on Daily Biological Rhythm and Mental Performance in Healthy Young Adults

A study testing Increasing or decreasing daily total fluid intake in people with Healthy and Habitual; Drinking, run by Liverpool John Moores University at 1 site in United Kingdom.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

Chronic low water intake may raise the risk of morbidity and mortality by influencing key water regulating hormones (e.g., AVP), which are known to modulate glucoregulation and renal function. Read more about this study

Who is it for?
Ages 18 to 35 yearsHealthy volunteers can take part
Conditions the study is for
Healthy, Habitual; Drinking, Stress, Physiological
What is being tested?
Increasing or decreasing daily total fluid intake
Could I receive a placebo?
No, everyone receives an active treatment
How many people
71 participants
Where
1 siteUnited Kingdom
Study dates
24 Nov 2022to 21 Mar 2024
Phase
Interventional
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 35 years
  • All sexes
  • Healthy volunteers accepted
  • Adult

Who may be able to join

  • Participants who...
  • are free-living, who fully understands and agree to the objectives of the study, who gave signed and dated informed consent, which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in this protocol
  • have read and signed the study informed consent.
  • are overtly healthy men and current COC using women (taking COC for at least 3-months and should they be eligible and willing to participate, are happy to continue taking COC during their study participation) aged 18-35 years who engage in <5 hours of physical activity per week (in accordance with previously defined classifications). This information will be obtained during the initial study brief and using the health screening questionnaire.
  • have a habitual fluid consumption of ≤ 1.6 L/day OR ≥ 2.9 L/day for men and ≤ 1.5 L/day OR ≥ 2.5 L/day for women, verified by 7-day fluid intake record.
  • have a verified UOsm aligned with the following and ≤ 28% day-to-day differences in UOsm; this will be determined during the TFI screening week and familiarisation visit 1: IF habitual low TFI, i.e., TFI ≤ 1.5 L/day for women OR ≤ 1.6 L/day for men have a UOsm ≥ 500 mOsm/kg OR IF habitual high TFI, i.e., TFI ≥ 2.5 L/day for women OR ≥ 2.9 L/day for men have a UOsm < 500 mOsm/kg.
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  • have access to a domestic fridge at home so that urine samples can be stored prior to laboratory visits.
  • have a body mass index (BMI) <30 kg/m2.
  • have an IOS or Android smart phone and therefore the ability to download the HidrateSpark and MyFitnessPal mobile applications.

Who cannot join

  • Participants who…
  • had any surgery or intervention requiring a general anaesthesia in the preceding 4 weeks, or who plans to have one during the study.
  • have a history of chronic metabolic or gastrointestinal disease, or gastrointestinal surgery except for appendectomy.
  • has chronic or iatrogenic immunodeficiency (e.g., Chemotherapy, HIV).
  • present a severe evolutive or chronic pathology (e.g., cancer, tuberculosis, Crohn's disease, cirrhosis, multiple sclerosis, Type I diabetes…).
  • have cardiac, respiratory (including asthma) or renal insufficiency, cardiomyopathy, valvopathy and medical history of rheumatic fever.
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  • are receiving (currently or in the 4 last weeks) systemic treatment or topical treatment likely to interfere with the study parameters; specifically, relating to the stress response (e.g., steroid treatment may influence cortisol response) and hydration regulation (e.g., diuretics). Other excluded medications include antibiotics, intestinal or respiratory antiseptics, anti-rheumatics, antiphlogistics (except aspirin or equivalent at doses preventing from aggregation of platelets or blood clotting), anti-inflammatory and steroids prescribed in chronic inflammatory diseases.
  • are taking any treatment for anorexia, weight loss, or any form of treatment likely to interfere with metabolism or dietary habits (e.g., diuretic, hypolipemic, hypoglycemic treatments).
  • have a clinically diagnosed psychiatric disorder.
  • have a clinically diagnosed sleeping disorder.
  • have a clinically diagnosed gambling addiction.
  • are involved in any other clinical study within the preceding month or in the exclusion period after another clinical study.
  • changes his/her dietary habits within the preceding 4 weeks (for instance start of a diet high in fibres).
  • have a diagnosed eating disorder.
  • have a special medicated diet (for obesity, anorexia, metabolic pathology…).
  • plan to modify her/his dietary habits.
  • •...have a daily total fluid intake of: Men: between 1.6 litres per day and 2.9 litres per day OR Women: between 1.5 litres per day and 2.5 litres per day.
  • have a UOsm of (determined during TFI screening week and familiarisation visit 1):Men: <500 mOsm/kg if habitual TFI is ≤ 1.6 L/day or ≥ 500 mOsm/kg if habitual TFI ≥ 2.9 L/day OR Women: <500 mOsm/kg if habitual TFI is ≤ 1.5 L/day or ≥ 500 mOsm/kg if habitual TFI ≥ 2.5 L/day.
  • have a day-to-day variation in UOsm >28% (determined during TFI screening week and familiarisation visit 1)
  • habitually consume >1.3 L/day of hot beverages i.e., tea, coffee (1.3L equates to 4 average sized mugs) as estimated by a fluid intake record questionnaire.
  • consumes ≥ 91 units of alcohol per month (equivalent to more than 3 pints of beer per day or more than 3 large glasses of red wine per day).
  • are vulnerable defined as individuals whose willingness to volunteer in the clinical trial may be unduly influenced by the expectation, whether justified or not, of benefits associated with participation, or of a retaliatory response from senior members of a hierarchy in case of refusal to participate (Examples are members of a group with a hierarchical structure linked to the Investigator or to the Sponsor, subordinate laboratory personnel, and employees of the Investigator or of the Sponsor).
  • are women not currently on COC i.e., naturally menstruating, or on progestogen only forms of contraception (i.e., IUS, mini-pill, implant, injection).
  • are women using COC for <3-months prior to reading the participant information sheet or not planning to continue taking COC during their potential participation in the study.
  • are pregnant woman as assessed by a questionnaire or woman planning to become pregnant during the study, breast-feeding woman.
  • are expected to be living in the same home as a current participant.
  • are a current smoker.
  • are not able to answer questionnaires by writing whatever the reason.
  • have a loss of personal liberty, by administrative or judicial decision.
  • are major but with a legal guardian.
  • engage in >5 hours physical activity a week.
  • do not have access to a domestic fridge at home so that urine samples can be stored prior to laboratory visits.
  • do not have an IOS or Android smart phone and therefore the ability to download the HidrateSpark and MyFitnessPal mobile applications.

Trial locations and contacts

1 site in 1 country.

United Kingdom1 site

  • Liverpool John Moores University

    Liverpool, Merseyside, L3 3AF

Other trials in United Kingdom

About this study

Official title: Investigating the Influence of Fluid Intake on Saliva Cortisol: Diurnal Variation and Acute Response to Psychological Stress in Young Adults

Chronic low water intake may raise the risk of morbidity and mortality by influencing key water regulating hormones (e.g., AVP), which are known to modulate glucoregulation and renal function. For example, AVP stimulates the HPA axis to release the glucocorticoid stress hormone cortisol with potentially far-reaching effects on metabolism, immunity and inflammation. One study observed elevated blood cortisol in a group of low water drinkers, albeit cortisol was measured at one time of day only. However, in the field of psychobiology, researchers have traditionally related more dynamic assessments of cortisol with health outcomes; by evoking cortisol responses to acute standardised laboratory stressors, such as The Trier social stress test. More recently, researchers have appreciated the importance of circadian variability in cortisol levels, by examining influences on, and consequences of individual differences in the diurnal variation of cortisol. The major measurable parameters of the diurnal variation are; the cortisol awakening response (CAR), which is the rise in cortisol during the first 30-45 minutes following awakening, and the diurnal cortisol slope, which is the rate of decline in cortisol levels across the day, from morning to evening. These parameters are considered to reflect different aspects of HPA axis function; with the CAR best reflecting the adrenal capacity to respond to stress and awakening and diurnal slope more indicative of daily cortisol exposure. Although distinct, both blunted CAR and a flattened diurnal cortisol slope appear to be consistent markers of HPA axis dysfunction and related to a variety of poor health outcomes. Therefore, it has been recommended that contemporary research should simultaneously estimate an individual's awakening cortisol responsiveness, and diurnal slope, thereby capturing distinct and important components of HPA axis function. The shared pathways that regulate body water, diurnal variation in cortisol and our response to stress underpin the broad aim of this research programme: to investigate the influence of low and high fluid intake on diurnal cortisol variation and the cortisol response to acute stress.

The aims of this study are to investigate:

  1. The influence of a change in water intake behaviour on diurnal saliva cortisol variation as assessed by the CAR (primary outcome)
  2. The influence of a change in water intake behaviour on biomarkers of hydration and thirst as assessed by urine osmolality, urine colour and thirst sensation.
  3. The influence of habitual low and high total fluid intake on saliva cortisol response to an acute psychological stress (secondary outcome)
  4. Investigate the influence of a change in water intake behaviour on plasma biomarkers of hydration as assessed by plasma osmolality and plasma copeptin (exploratory outcome)
Being tested
Increasing or decreasing daily total fluid intake
Medical subject headings
Stress, Psychological

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Increasing or decreasing daily total fluid intakeBehavioural

    1-week intervention where the intake of drinking water will either be increased (if habitually low) or decreased (if habitually high). The total fluid intake (TFI) prescriptions during the intervention are derived from the mean TFI of habitually high and habitually low drinkers from a sex, age and country matched population. Specifically, habitually high drinkers will be permitted a TFI of 1.3 L/day and habitually low drinkers will be permitted a TFI of 3.5 L/day for men and 3.3 L/day for women. Participants will be instructed to maintain their usual intake of other beverages i.e., tea/coffee to achieve their target TFI. The diurnal saliva cortisol response at rest will be examined at the end of both experimental periods and the saliva cortisol response to an acute psychological stress will be examined at the end of the habitual experimental period only.

Study groups in NCT05491122
Study groupRoleWhat they receive
Habitual periodNo intervention8 consecutive days where participants will drink fluids as they do habitually (habitually low TFI = ≤ 1.6 L/day, women ≤ 1.5 L/day, or habitually high TFI = men ≥ 2.9 L/day, women ≥ 2.5 L/day)
Intervention periodExperimental1-week where the fluid intake will be modified. Habitually high drinkers will be permitted a TFI of 1.3 L/day and habitually low drinkers will be permitted a TFI of 3.5 L/day for men and 3.3 L/day for women. Participants will be instructed to maintain their usual intake of other beverages i.e., tea/coffee to achieve their target TFI.
Receives: Behavioral: Increasing or decreasing daily total fluid intake

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Cortisol awakening response (CAR)

    A biomarker for Hypothalamic Pituitary Adrenal activity; a naturally occurring increase in cortisol upon waking, assessed by ELISA

    Measured: Assessed during the first 45 minutes after awakening

Secondary outcomes (4)

  1. Urine Osmolality

    The concentration of osmotic solutes present in the urine, measured using a freezing point depression osmometer;

    Measured: Mid-afternoon urine samples will be collected on days 2, 5, 6 and 7 during the habitual and on days 10, 13 and 14 of the intervention periods. T

  2. Change in saliva cortisol to acute psychological stress

    Changes in the concentration of saliva free cortisol assessed by ELISA

    Measured: Delta changes (increase/ decrease) in cortisol response (calculated by subtracting the baseline cortisol value from the peak post-stress induction level (-30 minutes pre-stress minus 10 minutes post-stress)

  3. Urine colour

    urine colour which is a common urinary marker used for assessing hydration status, assessed using a urine colour chart has been developed to assess urine concentration in healthy humans;

    Measured: Mid-afternoon urine samples will be collected on days 2, 5, 6 and 7 during the habitual and on days 10, 13 and 14 of the intervention periods. T

  4. Thirst sensation

    subjective rating of thirst will be obtained from a 0-9 thirst sensation scale (0 = "not thirsty at all" to 9 = "very, very thirsty")

    Measured: hirst sensation will be collected for daily for a total of 15 days across the habitual and intervention periods.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted8 Aug 2022
  2. Study start24 Nov 2022
  3. Primary completion21 Mar 2024
  4. Study completion21 Mar 2024

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Basic science
Allocation
Non-randomised
Intervention model
Parallel groups
Model description
Participants will be screened to identify habitually low, i.e., total fluid intake: men ≤ 1.6 L/day, women ≤ 1.5 L/day and high i.e., total fluid intake: men ≥ 2.9 L/day, women ≥ 2.5 L/day drinkers. Each subject will undergo two different and consecutive experimental periods: 8 days on habitual fluid intake and a 1-week intervention where the intake of drinking water will either be increased (if habitually low) or decreased (if habitually high). The total fluid intake (TFI) prescriptions during the intervention are derived from the mean TFI of habitually high and habitually low drinkers from a sex, age and country matched population. Specifically, habitually high drinkers will be permitted a TFI of 1.3 L/day and habitually low drinkers will be permitted a TFI of 3.5 L/day for men and 3.3 L/day for women. Participants will be instructed to maintain their usual intake of other beverages i.e., tea/coffee to achieve their target TFI.
Masking
None (open label)
Enrolment
71 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05491122
Sponsor's protocol ID
ORION Study 2
Status last verified
Jun 2022
First submitted
1 Aug 2022
Last updated
19 Mar 2025
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Publications

  • Kashi DS, Hunter M, Edwards JP, Zemdegs J, Lourenco J, Mille AC, Perrier ET, Dolci A, Walsh NP. Habitual fluid intake and hydration status influence cortisol reactivity to acute psychosocial stress. J Appl Physiol (1985). 2025 Sep 1;139(3):698-708. doi: 10.1152/japplphysiol.00408.2025. Epub 2025 Aug 13.

    PubMed 40803748

Questions about this trial

What is this clinical trial studying?

A study testing Increasing or decreasing daily total fluid intake in people with Healthy and Habitual; Drinking, run by Liverpool John Moores University at 1 site in United Kingdom.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 9 inclusion and 33 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 19 Mar 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Cortisol awakening response (CAR) (time frame: Assessed during the first 45 minutes after awakening). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05491122, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 19 Mar 2025.

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