Mental AcuityNCT07654270
The Effect of Water Temperature on Heart Rate Variability and Cognition
A study testing water in people with Mental Acuity, run by Arizona State University at 1 site in United States.
Trial summary
Heart rate variability (HRV) is a key indicator of fitness, and stress resilience. Previous research has shown that HRV decreases under mental workload, including during tasks that require strict attention. Read more about this study
- Who is it for?
- Ages 18 to 30 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Mental Acuity
- What is being tested?
- water
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 30 participants
- Where
- 1 siteUnited States
- Study dates
- 13 Jul 2026to 15 Jun 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
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 30 years
- Women only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy women free of chronic disease (by self-report)
- 18-30 years of age
Who cannot join
- medication/drug use that has not been consistent for the previous 3 months or will be discontinued during the trial
- any acute illness
- regular use of cigarettes or marijuana
- pregnant or lactating women
- not fluent in English
- not willing to attend two in-person lab visits in downtown Phoenix and follow study protocol (including abstaining from caffeine in the 12 hours prior to testing)
- not currently competing in sports or unusually high-intensity exercise protocols (e.g., high-intensity exercise greater than 30 minutes most days of the week)
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Health North ASU Downtown Campus
Phoenix, Arizona, 85004
Carol Johnston, 6024962539, carol.johnston@asu.edu
About this study
Official title: Effects of Water Temperature on Heart Rate Variability During Cognitive Testing in Healthy Adult Women: A Randomized Crossover Trial
Heart rate variability (HRV) is a key indicator of fitness, and stress resilience. Previous research has shown that HRV decreases under mental workload, including during tasks that require strict attention. Studies also show that temperature exposure affects attention: cold increases the stress response while warm water has a calming effect. Very few studies combine thermal exposure with cognitive testing, and no controlled trials have investigated whether water temperature modulates HRV responses specifically during cognitive demand.
Read the detailed description
Heart rate variability (HRV) is a widely recognized physiological marker that reflects the dynamic interaction between the cardiovascular and autonomic nervous systems. HRV represents millisecond-level fluctuations in time between consecutive heartbeats. It is a key indicator of autonomic nervous system balance, with higher values indicate better recovery, fitness, and stress resilience. Previous research has shown that HRV decreases under mental workload, including during tasks that require attention, inhibition, or executive function.1-3 Studies also show that temperature exposure affects autonomic regulation: cold increases sympathetic drive, while warm water supports parasympathetic activation.4-6 Very few studies combine thermal exposure with cognitive testing, and no controlled trials have investigated whether water temperature modulates HRV responses specifically during cognitive demand.
- Conditions
- Mental Acuity
- Being tested
- water
- Keywords
- heart rate variability, water temperature, cognitive performance
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
waterOther
water temperature
| Study group | Role | What they receive |
|---|---|---|
| Warm water | Experimental | Water will be heated to ~55º C (131 ºF) Receives: Other: water |
| Cold water | Placebo comparator | Cold water: 4-6º C (41ºF) Receives: Other: water |
What is being measured
The primary outcome is the main question the study is designed to answer.
heart rate variability
the measure of the variation in time between consecutive heartbeats
Measured: 3 minutes
cognitive performance
Trail making test that measures cognitive flexibility, visual attention, and executive function, with interpretation based on completion times (in seconds)
Measured: 3 minutes
Secondary outcomes (2)
cognitive performance
Stroop Color-Word Test which measures attention span, reaction time, and ability to resist distractions
Measured: 3 minutes
cognitive performance
reaction time: measured by the elapsed time between stimulus onset and an individual's response
Measured: 3 minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Jun 2026
- Study start13 Jul 2026
- Primary completion15 Dec 2026 (estimated)
- Study completion15 Jun 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Mental AcuityStudies of the same condition, open and under way.
- More trials run by Arizona State UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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
- Randomised
- Intervention model
- Crossover
- Model description
- This is a crossover study and all participants will receive both treatments one week apart in randomized order.
- Masking
- None (open label)
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Arizona State University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Carol Johnston, Arizona State University
- Investigators
- Carol Johnston, Principal investigator, Arizona State University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07654270
- Sponsor's protocol ID
- STUDY00024174
- Status last verified
- Nov 2026
- First submitted
- 10 Jun 2026
- Last updated
- 6 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 6 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Water Temperature on Heart Rate Variability During Cognitive Testing in Healthy Adult Women: A Randomized Crossover Trial
- ClinicalTrials.gov ID
- NCT07654270
- Acronym / sponsor ID
- STUDY00024174
- Conditions
- Mental Acuity
- Keywords
- heart rate variability, water temperature, cognitive performance
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- Arizona State UniversityUniversity, hospital or other
- Study start
- 13 Jul 2026 (actual)
- Primary completion
- 15 Dec 2026 (estimated)
- Study completion
- 15 Jun 2027 (estimated)
- First posted
- 17 Jun 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Heart rate variability (HRV) is a key indicator of fitness, and stress resilience. Previous research has shown that HRV decreases under mental workload, including during tasks that require strict attention. Studies also show that temperature exposure affects attention: cold increases the stress response while warm water has a calming effect. Very few studies combine thermal exposure with cognitive testing, and no controlled trials have investigated whether water temperature modulates HRV responses specifically during cognitive demand.
Detailed description
Heart rate variability (HRV) is a widely recognized physiological marker that reflects the dynamic interaction between the cardiovascular and autonomic nervous systems. HRV represents millisecond-level fluctuations in time between consecutive heartbeats. It is a key indicator of autonomic nervous system balance, with higher values indicate better recovery, fitness, and stress resilience. Previous research has shown that HRV decreases under mental workload, including during tasks that require attention, inhibition, or executive function.1-3 Studies also show that temperature exposure affects autonomic regulation: cold increases sympathetic drive, while warm water supports parasympathetic activation.4-6 Very few studies combine thermal exposure with cognitive testing, and no controlled trials have investigated whether water temperature modulates HRV responses specifically during cognitive demand.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- This is a crossover study and all participants will receive both treatments one week apart in randomized order.
| Arm | Type | Receives |
|---|---|---|
| Warm water | Experimental | Other: waterWater will be heated to ~55º C (131 ºF) |
| Cold water | Placebo comparator | Other: waterCold water: 4-6º C (41ºF) |
Who may qualify
- Ages
- 18 to 30 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- Healthy women free of chronic disease (by self-report)
- 18-30 years of age
Key exclusion criteria (7 listed)
- medication/drug use that has not been consistent for the previous 3 months or will be discontinued during the trial
- any acute illness
- regular use of cigarettes or marijuana
- pregnant or lactating women
- not fluent in English
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| waterwater temperature | Other | Cold water, Warm water |
Primary outcome
heart rate variability
Time frame: 3 minutes
the measure of the variation in time between consecutive heartbeats
cognitive performance
Time frame: 3 minutes
Trail making test that measures cognitive flexibility, visual attention, and executive function, with interpretation based on completion times (in seconds)
2 secondary outcomes
cognitive performance
Time frame: 3 minutes
cognitive performance
Time frame: 3 minutes
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Nov 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Carol Johnston principal investigator
Arizona State University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing water in people with Mental Acuity, run by Arizona State University at 1 site in United States.
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 2 inclusion and 7 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: looking for participants now, as of the sponsor's last update on 6 Nov 2026. 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 States. 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. Some participants in this study may receive a placebo. 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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Carol Johnston (6024963463, carol.johnston@asu.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
heart rate variability (time frame: 3 minutes). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 6 Nov 2026.