Clinical trial NCT06279897: LBNP Tolerance With Skin Warming After Exercise Cold Stress
Official title: Skin Rewarming After Exercise Cold Stress and Tolerance to Simulated Blood Loss
Study type: INTERVENTIONAL
Overall status: ACTIVE_NOT_RECRUITING
Phase: NA
Conditions: Blood Pressure
Blood Loss
Keywords: Arterial Blood Pressure
Permissive Hypotension
Cold Stress
Skin Warming
Blood Loss
Lead sponsor: University of Colorado, Colorado Springs
Sponsor class: OTHER
First posted: 2024-02-28
Enrollment: 10
Sex: ALL
Minimum age (years): 18
Maximum age (years): 40
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Intervention model description: Participants will complete trial 1 at the beginning of the study. Participants will then complete trials 2 through 5 in a random, counterbalanced order.
Primary purpose: BASIC_SCIENCE

Brief summary: Assess the effect of skin rewarming during lower body negative pressure upon arterial blood pressure and tolerance to simulated blood loss after exercise in the cold.

Detailed description: Individuals who have experienced a hemorrhagic insult are often wrapped in a warm blanket. In individuals who have exercise in a cold environment, it is unknown how this skin warming influence tolerance to simulated blood loss and whether there is an optimal temperature to warm the skin up to in order to lower blood pressure (permissive hypotension).

After an initial study visit to examine exercise capacity (Visit 1), participants will complete four trials (Visits 2 through 5) After exercise in a cold environment, participants will have cold skin temperatures (\~82°F; Visit 2). Researchers will examine how increasing skin temperature to normal (\~90°F; Visit 3), warm (93°F; Visit 4) and hot (95°F; Visit 5) influences arterial blood pressure and tolerance to simulated blood loss compared to when the skin remains cold.

This project will test the hypothesis that skin rewarming to \~95°F lowers arterial blood pressure without impairing tolerance to simulated blood loss (lower body negative pressure; LBNP) relative to when the skin is kept cold (82°F).

Primary data include core and skin temperatures, arterial blood pressure and LBNP tolerance time. Secondary variables include skin blood flow and heart rate. After completing visit 1 first, all participants will complete visits 2 through 5 in a randomized order and participants are blinded. The order will be counterbalanced between participants.

Eligibility criteria: Inclusion Criteria:

* 18 and 40 years old
* free of known disease and illness
* Speak English
* Systolic blood pressure \<140mmHg
* Diastolic blood pressure \<90 mmHg

Exclusion Criteria:

* Currently pregnant or breast feeding
* Individuals with diagnosed with cardiac, respiratory, neurological and/or metabolic illness or disease.
* Currently taking prescribed or over the counter medications known to influence the cardiovascular, pulmonary, renal and/or central nervous system.
* Current use of tobacco or nicotine products
* Any physical limitations that impede completion of the tests, such as exercise tests will also be an exclusion criteria.
* Body mass\< 80 pounds body weight
* Appendectomy

Primary outcomes:
measure: Arterial blood pressure
timeFrame: Before and during lower body negative pressure (LBNP) procedure
measure: Tolerance to simulated blood loss
timeFrame: Lower body negative pressure test duration in all trials.
Secondary outcomes:
measure: Core temperature
timeFrame: Throughout exercise cold exposure and continuously during LBNP
measure: Cutaneous Vascular Conductance
timeFrame: Before and during lower body negative pressure (LBNP) procedure
Other outcomes:
Locations:
city: Colorado Springs
country: United States
facility: University of Colorado Colorado Springs
state: Colorado
Study officials:
affiliation: Univeristy of Colorado Colorado Springs
name: James Pearson, PhD
role: PRINCIPAL_INVESTIGATOR
References: