Muscle and Body Temperature Responses During Uphill and Downhill Running

NCT05491382 | Withdrawn

• 1 other identifier: 1864889
• Study Type: interventional
• Target: N/A
• Locations: 0 countries
• Sites: N/A

Brief Summary

In animal models of thermoregulation (how the body regulates heat), heat-sensitive nerve cells that help regulate body temperature have been identified throughout the body (e.g. in muscles, viscera, and blood vessels, among others); however, in human thermoregulation models, only two locations are generally recognized: the core (brain) and the skin. The limited number of recognized locations in humans are likely due to the difficulty in testing these locations in humans, as these locations are typically identified in animals by sedating them, surgically opening them up, stimulating the area of interest with a hot or cold probe, and then measure thermoregulatory responses. Based on the literature, the researchers believe that by having participants run at the same energy expenditure but at three different inclines (uphill, downhill and flat) on a treadmill, the researchers can independently alter muscle temperature, while keeping core and skin temperature the same. Additionally, recent studies have suggested that temperature has a greater role at regulating blood flow through muscle tissue than previously recognized. Because of this, the researchers aim to have a second arm of the study to see whether these differences in muscle temperature result in differences in post-exercise blood flow to the muscle. Finally, downhill running is often used to study exercise-induced muscle damage, due to the greater breaking forces compared to flat land running. Because of this, a third study aim will be to examine the association between fitness level, body morphology and sex on exercise-induced muscle damage.

Conditions

Body Temperature Changes; Exercise; Blood Pressure

Outcome Measures

Primary Outcomes (9)

• Core temperature

  Measured by rectal and esophageal temperature

  Immediately after completing the intervention

• Skin temperature

  Measured at 8 sites using the ISO 9886 weighting system

  Immediately after completing the intervention

• Muscle temperature

  Measured at 4 locations: vastus lateralis, bicep femoris, lateral gastrocnemius and deltoid

  Immediately after completing the intervention

• Whole-body sweat rate (arm 1)

  Measured pre and post exercise with a platform scale (accurate to 1 g)

  Immediately after completing the intervention

• Femoral blood flow (arm 2)

  Measured using Ultrasound Doppler

  1 hour after completing the intervention

• Blood pressure (arm 2)

  Measured using a standard blood pressure cuff and finger photoplethysmography

  1 hour after completing the intervention

• Perceived muscle pain (arm 3)

  Self-reported on a 100 mm likert scale ranging from "no pain or discomfort" to "maximal pain and discomfort"

  Assessed 48 hours after the completing exercise

• Maximal voluntary contraction (arm 3)

  The maximal force (in N) generated by the right leg during an isometric leg extension, with the knee at 90 degrees

  Assessed 48 hours after the completing exercise

• Plasma creatinine levels (arm 3)

  Measured from blood taken from an ante cubital vein

  Assessed 48 hours after the completing exercise

Secondary Outcomes (6)

• Oxygen consumption

  Average oxygen consumption over the 60 min of exercise

• Local sweat rate

  Average local sweat rate over the 60 min of exercise

• Skin blood flow

  Average skin blood flow over the 60 min of exercise

• Heart rate

  Average heart rate over the 60 min of exercise

• Perceived exertion

  Average perceived exertion over the 60 min of exercise

Study Arms (3)

Does muscle temperature influence heat loss responses independently from core and skin temperature?

EXPERIMENTAL

The study will consist of three experimental trials, conducted in a randomized order, where participants will be required to run for one hour at \~60% of their maximal oxygen consumption on one of three different inclines: 1) flatland, 2) uphill, and 3) downhill. Environmental conditions will be maintained at 34°C/93°F and 20% relative humidity.

Procedure: Uphill running; Procedure: Flatland running; Procedure: Downhill running

Does muscle temperature influence muscle blood flow independently from core and skin temperature?

EXPERIMENTAL

Following the exercise protocol described above in Arm 1, the participants will then lay supine for one hour while their muscle and skin blood flow, as well as blood pressure are measured.

Procedure: Uphill running; Procedure: Flatland running; Procedure: Downhill running

What factors contribute to exercise-induced skeletal muscle damage?

EXPERIMENTAL

For those participants who additionally agree to participate in the muscle microdamage portion of the study, participants will be asked to return to the lab 24h and 48h post-trial. During these subsequent follow-up sessions, an additional blood sample will be drawn from the participants, the participants maximal voluntary contraction and muscle pain will be assessed, and they will be asked to fill out the muscle soreness scale.

Procedure: Uphill running; Procedure: Flatland running; Procedure: Downhill running

Interventions

Uphill running PROCEDURE

Participants will run at 70% of their maximal oxygen consumption for 60 min at a 10 degree (17.6%) incline.

Does muscle temperature influence heat loss responses independently from core and skin temperature?; Does muscle temperature influence muscle blood flow independently from core and skin temperature?; What factors contribute to exercise-induced skeletal muscle damage?

Flatland running PROCEDURE

Participants will run at 70% of their maximal oxygen consumption for 60 min at a 0 degree (0%) incline.

Does muscle temperature influence heat loss responses independently from core and skin temperature?; Does muscle temperature influence muscle blood flow independently from core and skin temperature?; What factors contribute to exercise-induced skeletal muscle damage?

Downhill running PROCEDURE

Participants will run at 70% of their maximal oxygen consumption for 60 min at a -10 degree (-17.6%) decline.

Does muscle temperature influence heat loss responses independently from core and skin temperature?; Does muscle temperature influence muscle blood flow independently from core and skin temperature?; What factors contribute to exercise-induced skeletal muscle damage?

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• All participants must be healthy with no history of respiratory, metabolic, cardiovascular, blood pressure disease, or of diabetes and must not currently be on any medication related to these or any other conditions. Additionally, due to the potential dangers of elevated body temperatures to the unborn fetus, all female participants must not be pregnant and agree to not to attempt to become pregnant throughout their involvement in the study.

You may not qualify if:

• Unhealthy, history of respiratory, metabolic, cardiovascular, blood pressure disease, or of diabetes, currently taking medications related to these or that have the possibility of impairing cardiovascular or thermoregulatory function. Any participants that are pregnant.

Sponsors & Collaborators

• CommonSpirit Health: lead
• University of Colorado, Colorado Springs: collaborator

MeSH Terms

Conditions

Body Temperature Changes; Motor Activity

Condition Hierarchy (Ancestors)

Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Behavior

Study Officials

• Nathan B Morris, PhD

  University of Colorado, Colorado Springs

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 26, 2022
• First Posted: August 8, 2022
• Study Start: December 1, 2024
• Primary Completion: December 1, 2025
• Study Completion (Estimated): December 1, 2026
• Last Updated: February 18, 2025

Record last verified: 2023-12

Data Sharing

• IPD Sharing: Will share
• Time Frame: Data will be posted upon completion of the study, when the manuscripts are submitted for publication. This data will be available at the provided link for the foreseeable future.
• Access Criteria: Open to all.