Cold ExposureNCT05464758
The Effects of Cold Adaptation on Skin Blood Flow, Hand Function, and Comfort in Healthy Adults
A study testing Repeated cold exposure in people with Cold Exposure, run by United States Army Research Institute of Environmental Medicine at 1 site in United States.
Trial summary
In cold weather environments, blood flow to the extremities is significantly reduced, which severely impairs hand function and induces thermal discomfort. Prolonged or repeated cold exposure elicits an adaptive habituation response that is characterized by blunted skin vasoconstriction and thus may be an effective… Read more about this study
- Who is it for?
- Ages 18 to 39 yearsHealthy volunteers can take part
- Conditions the study is for
- Cold Exposure
- What is being tested?
- Repeated cold exposure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 16 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Aug 2022to 13 Sep 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 39 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Male or female, age 18-39
- In good health as determined by OMSO (Office of Medical Support and Oversight)
- Willing to refrain from exercise and caffeinated or alcoholic beverages for 12 hours before each testing session
- Willing to refrain from smoking or tobacco use 8 hours before each testing session
Who cannot join
- History of cold injuries of any severity (e.g., frostbite, trench foot, chilblains).
- Raynaud's syndrome.
- Cold-induced asthma/bronchospasm
- Previous hand/finger injuries that impair dexterity and hand function.
- Metal hardware (plates/screws) in the forearms and hands.
- Current use of medications or dietary supplements that could alter cardiovascular, thermoregulatory, or vascular control (e.g., anti-hypertensives, statins).
Show all 11Show fewer
- Known allergies to medical adhesives.
- Heart, lung, kidney, muscle, or nerve disorder(s)
- A planned MRI during the study or within 2 days after completing a cold test.
- Women who are pregnant, planning to become pregnant, or breastfeeding.
- Not willing to have small areas of skin on the body shaved (if deemed necessary for attachment of study instrumentation)
Trial locations and contacts
1 site in 1 country.
United States1 site
U.S. Army Research Institute of Environmental Medicine
Natick, Massachusetts, 01760
About this study
Official title: The Effects of Cold Habituation on Peripheral Blood Flow, Hand Function, and Thermal Comfort
In cold weather environments, blood flow to the extremities is significantly reduced, which severely impairs hand function and induces thermal discomfort. Prolonged or repeated cold exposure elicits an adaptive habituation response that is characterized by blunted skin vasoconstriction and thus may be an effective strategy to improve peripheral perfusion, reduce thermal discomfort, and maintain hand function during cold weather military operations. Since mission conditions often involve low ambient temperatures, countermeasures that reduce cold-induced decrements in hand function and thermal comfort are important to enhance Warfighter readiness in cold weather battlefield environments. The goals of this study are to 1) evaluate the effectiveness of cold habituation in improving skin blood flow, hand function, and thermal comfort during cold exposure and 2) identify the mechanisms that contribute to improvements in skin blood flow following habituation.
Read the detailed description
Participants (n=15, 18-39 yrs) will complete a preliminary cold air exposure (baseline testing) followed by 8 days of repeated cold air exposures with minimal clothing. The cold exposures will be 2 hours in duration and will be conducted in 8°C (46°F) conditions. Before and after the repeated cold exposures, participants will undergo hand function tests, assessments of thermal comfort, and skin blood flow testing.
- Conditions
- Cold Exposure
- Being tested
- Repeated cold exposure
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Repeated cold exposureOther
8 consecutive days of exposure to 8°C air for 120 minutes each day
| Study group | Role | What they receive |
|---|---|---|
| Cold habituation | Experimental | 8-day cold habituation Receives: Other: Repeated cold exposure |
What is being measured
The primary outcome is the main question the study is designed to answer.
Skin blood flow
Skin blood flow will be measured using non-invasive laser-Doppler flowmetry probes before and during cold exposure. Output (red blood cell flux) will be divided by mean arterial blood pressure to give an index of cutaneous vascular conductance [CVC, flux/mmHg].
Measured: 8 days
Skin temperature
Skin temperatures [in °C] at up to 10 sites on the body will be measured using skin thermistors before and during cold exposure. Hand and foot skin temperatures will also be measured with a thermography imaging camera.
Measured: 8 days
Manual dexterity - Pegboard
Pegboard scores will be obtained before and during cold exposure. Scores are the number of pegs placed into the boards.
Measured: 3 days
Manual dexterity - Minnesota Rate of Manipulation
Minnesota Rate of Manipulation dexterity scores will be obtained before and during cold exposure. Scores are the time [in seconds] required to move small blocks various distances.
Measured: 3 days
Hand and finger strength
Pinch and hand strength [in kg] will be measured using a pinch meter and grip strength device (dynamometer). Participants will complete three pinch strength tests and one grip strength test before and during cold exposure.
Measured: 3 days
Cold perception
Ratings of thermal comfort, thermal sensation, and pain perception [in arbitrary units] will be assessed using visual analogue scales before and during cold exposure.
Measured: 5 days
Secondary outcomes (5)
Metabolic heat production
Oxygen consumption and carbon dioxide production [ml/kg/min] will be measured using computerized indirect calorimetry before and during cold exposure. Oxygen consumption and carbon dioxide production will be combined to report metabolic heat production in Watts per meter squared.
Measured: 5 days
Body core temperature
Body core temperature [in °C] will be measured using a telemetry pill self-inserted as a suppository during cold exposure.
Measured: 5 days
Blood pressure
Brachial artery blood pressure [in mmHg] will be measured using an automated blood pressure cuff before and during cold exposure.
Measured: 12 days
Plasma norepinephrine
Circulating concentrations of norepinephrine [in pg/ml] will be assessed in blood collected via venipuncture before and after cold exposure.
Measured: 3 days
Heart rate
Heart rate [in beats per min] will be measured using an automated cuff before and during cold exposure.
Measured: 12 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Jul 2022
- Study start1 Aug 2022
- Primary completion13 Sep 2024
- Study completion13 Sep 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Cold ExposureStudies of the same condition, open and under way.
- 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
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 16 participants (actual)
Sponsor and investigators
- Lead sponsor
- United States Army Research Institute of Environmental Medicine
- Sponsor type
- US federal agency
- Responsible party
- Sponsor
- Investigators
- Billie K Alba, Ph.D., Principal investigator, United States Army Research Institute of Environmental Medicine
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05464758
- Sponsor's protocol ID
- 21-04H
- Other IDs
- MO210025
- Status last verified
- Dec 2025
- First submitted
- 6 Jul 2022
- Last updated
- 26 Dec 2025
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 26 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effects of Cold Habituation on Peripheral Blood Flow, Hand Function, and Thermal Comfort
- ClinicalTrials.gov ID
- NCT05464758
- Acronym / sponsor ID
- 21-04H
- Conditions
- Cold Exposure
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 16 participants (actual)
- Lead sponsor
- United States Army Research Institute of Environmental MedicineUS federal agency
- Study start
- 1 Aug 2022 (actual)
- Primary completion
- 13 Sep 2024 (actual)
- Study completion
- 13 Sep 2024 (actual)
- First posted
- 19 Jul 2022 (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.
In cold weather environments, blood flow to the extremities is significantly reduced, which severely impairs hand function and induces thermal discomfort. Prolonged or repeated cold exposure elicits an adaptive habituation response that is characterized by blunted skin vasoconstriction and thus may be an effective strategy to improve peripheral perfusion, reduce thermal discomfort, and maintain hand function during cold weather military operations. Since mission conditions often involve low ambient temperatures, countermeasures that reduce cold-induced decrements in hand function and thermal comfort are important to enhance Warfighter readiness in cold weather battlefield environments. The goals of this study are to 1) evaluate the effectiveness of cold habituation in improving skin blood flow, hand function, and thermal comfort during cold exposure and 2) identify the mechanisms that contribute to improvements in skin blood flow following habituation.
Detailed description
Participants (n=15, 18-39 yrs) will complete a preliminary cold air exposure (baseline testing) followed by 8 days of repeated cold air exposures with minimal clothing. The cold exposures will be 2 hours in duration and will be conducted in 8°C (46°F) conditions. Before and after the repeated cold exposures, participants will undergo hand function tests, assessments of thermal comfort, and skin blood flow testing.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Cold habituation | Experimental | Other: Repeated cold exposure8-day cold habituation |
Who may qualify
- Ages
- 18 to 39 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Male or female, age 18-39
- In good health as determined by OMSO (Office of Medical Support and Oversight)
- Willing to refrain from exercise and caffeinated or alcoholic beverages for 12 hours before each testing session
- Willing to refrain from smoking or tobacco use 8 hours before each testing session
Key exclusion criteria (11 listed)
- History of cold injuries of any severity (e.g., frostbite, trench foot, chilblains).
- Raynaud's syndrome.
- Cold-induced asthma/bronchospasm
- Previous hand/finger injuries that impair dexterity and hand function.
- Metal hardware (plates/screws) in the forearms and hands.
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 |
|---|---|---|
| Repeated cold exposure8 consecutive days of exposure to 8°C air for 120 minutes each day | Other | Cold habituation |
Primary outcome
Skin blood flow
Time frame: 8 days
Skin blood flow will be measured using non-invasive laser-Doppler flowmetry probes before and during cold exposure. Output (red blood cell flux) will be divided by mean arterial blood pressure to give an index of cutaneous vascular conductance [CVC, flux/mmHg].
Skin temperature
Time frame: 8 days
Skin temperatures [in °C] at up to 10 sites on the body will be measured using skin thermistors before and during cold exposure. Hand and foot skin temperatures will also be measured with a thermography imaging camera.
Manual dexterity - Pegboard
Time frame: 3 days
Pegboard scores will be obtained before and during cold exposure. Scores are the number of pegs placed into the boards.
Manual dexterity - Minnesota Rate of Manipulation
Time frame: 3 days
Minnesota Rate of Manipulation dexterity scores will be obtained before and during cold exposure. Scores are the time [in seconds] required to move small blocks various distances.
Hand and finger strength
Time frame: 3 days
Pinch and hand strength [in kg] will be measured using a pinch meter and grip strength device (dynamometer). Participants will complete three pinch strength tests and one grip strength test before and during cold exposure.
Cold perception
Time frame: 5 days
Ratings of thermal comfort, thermal sensation, and pain perception [in arbitrary units] will be assessed using visual analogue scales before and during cold exposure.
5 secondary outcomes
Metabolic heat production
Time frame: 5 days
Body core temperature
Time frame: 5 days
Blood pressure
Time frame: 12 days
Plasma norepinephrine
Time frame: 3 days
Heart rate
Time frame: 12 days
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Dec 2025.
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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. This study is not recruiting at the moment.
Billie K Alba, Ph.D. principal investigator
United States Army Research Institute of Environmental Medicine
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Repeated cold exposure in people with Cold Exposure, run by United States Army Research Institute of Environmental Medicine 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 4 inclusion and 11 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 26 Dec 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 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. 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?
Skin blood flow (time frame: 8 days). The study lists 6 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 26 Dec 2025.