Home › NCT07654270

The Effect of Water Temperature on Heart Rate Variability and Cognition

Effects of Water Temperature on Heart Rate Variability During Cognitive Testing in Healthy Adult Women: A Randomized Crossover Trial

Who can join

Ages 18 to 30 · Women · Healthy volunteers welcome

Inclusion Criteria:

* Healthy women free of chronic disease (by self-report)
* 18-30 years of age

Exclusion Criteria:

* 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)

About the study

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.

What is being tested

• water (other)

Sponsor: Arizona State University · Participants: 30 · Started: Jul 13, 2026

Contact the study team

• Carol Johnston · Phone: 6024963463

Official record on ClinicalTrials.gov — NCT07654270

Locations in the U.S.

From ClinicalTrials.gov, data retrieved Nov 15, 2026. Each study sets its own eligibility; the study team decides who can join.