Mental Acuity
Conditions
Keywords
heart rate variability, water temperature, cognitive performance
Brief 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. 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.
Interventions
OTHERwater
water temperature
Sponsors
Arizona State University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
NONE
Masking description
Masking water temperature is not possible.
Intervention model description
This is a crossover study and all participants will receive both treatments one week apart in randomized order.
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 30 Years
Healthy volunteers
Yes
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)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| heart rate variability | 3 minutes | the measure of the variation in time between consecutive heartbeats |
| cognitive performance | 3 minutes | Trail making test that measures cognitive flexibility, visual attention, and executive function, with interpretation based on completion times (in seconds) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| cognitive performance | 3 minutes | Stroop Color-Word Test which measures attention span, reaction time, and ability to resist distractions |
Contacts
CONTACTCarol Johnston
PRINCIPAL_INVESTIGATORCarol Johnston
Arizona State University
Outcome results
None listed