LBNP Tolerance With Skin Warming After Exercise Cold Stress

University of Colorado, Colorado Springs

Status: Active, not recruiting

Conditions: Blood Loss; Blood Pressure

Treatments: Other: Skin Surface Rewarming; Other: Skin Surface Warming; Other: Skin Surface Cooling; Other: Skin Surface Heating

Study type: Interventional

Funder types: Other

Identifiers

NCT06279897

2023-068

Details and patient eligibility

About

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.

Full 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.

Enrollment: 10 patients

Sex: All

Ages: 18 to 40 years old

Volunteers: Accepts Healthy Volunteers

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

Trial design

Primary purpose: Basic Science

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

---

10 participants in 1 patient group

Skin Temperature Control During Simulated Blood Loss After Exercise Cold Stress

Experimental group

Description:

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.

Treatment:

Other: Skin Surface Heating

Other: Skin Surface Cooling

Other: Skin Surface Warming

Other: Skin Surface Rewarming