LBNP Tolerance With Skin Warming After Exercise Cold Stress

NCT ID: NCT06279897

Last Updated: 2025-03-27

Basic Information

• Recruitment Status: ACTIVE_NOT_RECRUITING
• Clinical Phase: NA
• Total Enrollment: 10 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2022-01-24
• Study Completion Date: 2026-09-30

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.

Conditions

Blood Pressure; Blood Loss

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: NONE

Study Groups

Skin Temperature Control During Simulated Blood Loss After Exercise Cold Stress

After exercise in the cold and participants skin will remain cold (\~82°F), be returned to normal (\~90°F), be slightly warmed (\~93°F) or heated (\~95°F) sixty seconds after the onset of LBNP.

Group Type: EXPERIMENTAL

Skin Surface Rewarming

Intervention Type: OTHER

Sixty seconds after the onset of lower body negative pressure (LBNP) skin temperature will be increased to \~90°F and held here for the duration of the LBNP test.

Skin Surface Warming

Intervention Type: OTHER

Sixty seconds after the onset of lower body negative pressure (LBNP) skin temperature will be increased to \~93°F and held here for the duration of the LBNP test.

Skin Surface Heating

Intervention Type: OTHER

Sixty seconds after the onset of lower body negative pressure (LBNP) skin temperature will be increased to \~95°F and held here for the duration of the LBNP test.

Skin Surface Cooling

Intervention Type: OTHER

Sixty seconds after the onset of lower body negative pressure (LBNP) skin temperature will remain lowered to \~82°F for the duration of the LBNP test.

Interventions

Skin Surface Rewarming

Sixty seconds after the onset of lower body negative pressure (LBNP) skin temperature will be increased to \~90°F and held here for the duration of the LBNP test.

Intervention Type: OTHER

Skin Surface Warming

Sixty seconds after the onset of lower body negative pressure (LBNP) skin temperature will be increased to \~93°F and held here for the duration of the LBNP test.

Intervention Type: OTHER

Skin Surface Heating

Sixty seconds after the onset of lower body negative pressure (LBNP) skin temperature will be increased to \~95°F and held here for the duration of the LBNP test.

Intervention Type: OTHER

Skin Surface Cooling

Sixty seconds after the onset of lower body negative pressure (LBNP) skin temperature will remain lowered to \~82°F for the duration of the LBNP test.

Intervention Type: OTHER

Other Intervention Names

Normothermic Trial; Warm Trial; Hot Trial; Cold Trial; Control Trial

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
• Body mass< 80 pounds body weight
• Appendectomy

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 40 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University of Colorado, Colorado Springs

OTHER

Sponsor Role: lead

Responsible Party

James Pearson

Associate Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

James Pearson, PhD

Role: PRINCIPAL_INVESTIGATOR

Univeristy of Colorado Colorado Springs

Locations

University of Colorado Colorado Springs

Colorado Springs, Colorado, United States

Countries

United States

Provided Documents

Document Type: Study Protocol and Informed Consent Form

View Document

Other Identifiers

2023-068

Identifier Type: -

Identifier Source: org_study_id