Predicting Responses to Exhausting, Prolonged, And Repeated Exercise Demands (PREPARED) for Heat

The overall goal of this project is to identify a work/rest cycle that allows for faster mission completion needed in emergency situations, compared to current Army heat guidance, while mitigating heat strain and neuromuscular fatigue. This project will determine the trade-off between faster mission completion and risk of heat strain and physical performance decrements. Completion of this project will allow military leaders to make informed decisions by understanding the impact of their choices on the magnitude of physical performance decrements and expected heat casualties, setting up hot weather missions for success.

Study Overview

• Status: Recruiting
• Conditions: Hyperthermia; Fatigue; Heat
• Intervention / Treatment: Other: 30/30 work/rest cycle; Other: 30/20 work/rest cycle; Other: 40/30 work/rest cycle; Other: 20/12 work/rest cycle

• Study Type: Interventional
• Enrollment (Estimated): 24
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Riana R Pryor, PhD; Phone Number: 7168295456; Email: rpryor@buffalo.edu

Study Locations

• United States
  • New York
    • Buffalo, New York, United States, 14214
      • Recruiting
      • Center for Research and Education in Special Environments
      • Contact: Riana R Pryor, PhD, ATC; Phone Number: 716-829-5456; Email: RPryor@buffalo.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Healthy individuals
• Physically active

Exclusion Criteria:

• History of cardiovascular, metabolic (such as clinical thyroid disease), respiratory, neural, or renal disease
• Hypertensive (systolic blood pressure > 139 mmHg, diastolic blood pressure > 89 mmHg) or tachycardic (heart rate > 100 bpm) during the screening visit
• Taking medications or supplements known to effect physiologic responses to exercise or thermoregulation (e.g., beta blockers, omega-3 fatty acids, statins, aspirin)
• Tobacco or nicotine use currently or in the past six months
• Musculoskeletal injury expected to impact exercise in the protocol
• A positive pregnancy test at any point in the study
• Study physician discretion based on any other medical condition or medication
• Inability to understand or follow instructions or the protocol
• Gastrointestinal disease or previous surgery prohibiting core temperature capsule use. Participants with a contraindication can opt to insert the pill rectally as a suppository.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: 30/30 work/rest cycle first; Participants will first complete the 30/30 work/rest cycle, and then complete the other three conditions in a randomized fashion	Other: 30/30 work/rest cycle; Participants will walk on a treadmill while wearing a weighted backpack to a work/rest cycle of 30 minutes of work followed by 30 minutes of rest.; Other: 30/20 work/rest cycle; Participants will walk on a treadmill while wearing a weighted backpack to a work/rest cycle of 30 minutes of work followed by 20 minutes of rest.; Other: 40/30 work/rest cycle; Participants will walk on a treadmill while wearing a weighted backpack to a work/rest cycle of 40 minutes of work followed by 30 minutes of rest.; Other: 20/12 work/rest cycle; Participants will walk on a treadmill while wearing a weighted backpack to a work/rest cycle of 20 minutes of work followed by 12 minutes of rest.
Experimental: 30/20 work/rest cycle first; Participants will first complete the 30/20 work/rest cycle, and then complete the other three conditions in a randomized fashion	Other: 30/30 work/rest cycle; Participants will walk on a treadmill while wearing a weighted backpack to a work/rest cycle of 30 minutes of work followed by 30 minutes of rest.; Other: 30/20 work/rest cycle; Participants will walk on a treadmill while wearing a weighted backpack to a work/rest cycle of 30 minutes of work followed by 20 minutes of rest.; Other: 40/30 work/rest cycle; Participants will walk on a treadmill while wearing a weighted backpack to a work/rest cycle of 40 minutes of work followed by 30 minutes of rest.; Other: 20/12 work/rest cycle; Participants will walk on a treadmill while wearing a weighted backpack to a work/rest cycle of 20 minutes of work followed by 12 minutes of rest.
Experimental: 40/30 work/rest cycle first; Participants will first complete the 40/30 work/rest cycle, and then complete the other three conditions in a randomized fashion	Other: 30/30 work/rest cycle; Participants will walk on a treadmill while wearing a weighted backpack to a work/rest cycle of 30 minutes of work followed by 30 minutes of rest.; Other: 30/20 work/rest cycle; Participants will walk on a treadmill while wearing a weighted backpack to a work/rest cycle of 30 minutes of work followed by 20 minutes of rest.; Other: 40/30 work/rest cycle; Participants will walk on a treadmill while wearing a weighted backpack to a work/rest cycle of 40 minutes of work followed by 30 minutes of rest.; Other: 20/12 work/rest cycle; Participants will walk on a treadmill while wearing a weighted backpack to a work/rest cycle of 20 minutes of work followed by 12 minutes of rest.
Experimental: 20/12 work/rest cycle first; Participants will first complete the 20/12 work/rest cycle, and then complete the other three conditions in a randomized fashion	Other: 30/30 work/rest cycle; Participants will walk on a treadmill while wearing a weighted backpack to a work/rest cycle of 30 minutes of work followed by 30 minutes of rest.; Other: 30/20 work/rest cycle; Participants will walk on a treadmill while wearing a weighted backpack to a work/rest cycle of 30 minutes of work followed by 20 minutes of rest.; Other: 40/30 work/rest cycle; Participants will walk on a treadmill while wearing a weighted backpack to a work/rest cycle of 40 minutes of work followed by 30 minutes of rest.; Other: 20/12 work/rest cycle; Participants will walk on a treadmill while wearing a weighted backpack to a work/rest cycle of 20 minutes of work followed by 12 minutes of rest.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Core temperature	Maximum gastrointestinal temperature reached during the work protocol	180 minutes of work
Isometric mid-thigh pull strength	Maximum voluntary contraction strength assessed using a force plate	180 minutes of work

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Metabolic cost	Collected expired air using a one-way mask will be analyzed using a metabolic cart to calculate metabolic heat production	180 minutes of work
Heart rate	Maximum heart rate measured using a telemetry strap throughout the work protocol	180 minutes of work
Mean skin temperature	Maximum skin temperature measured using buttons at four skin sites	180 minutes of work
Vastus lateralis electromyography	Wireless electromyography electrodes placed lengthwise over the vastus lateralis muscle belly	180 minutes of work

Collaborators and Investigators

• Sponsor: State University of New York at Buffalo
• Collaborators: United States Department of Defense
• Investigators: Principal Investigator: Riana R Pryor, PhD, University at Buffalo

Study record dates

Study Major Dates

• Study Start (Actual): November 1, 2024
• Primary Completion (Estimated): March 1, 2027
• Study Completion (Estimated): March 1, 2027

Study Registration Dates

• First Submitted: June 14, 2024
• First Submitted That Met QC Criteria: June 20, 2024
• First Posted (Actual): June 26, 2024

Study Record Updates

• Last Update Posted (Actual): January 26, 2026
• Last Update Submitted That Met QC Criteria: January 22, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Wounds and Injuries; Body Temperature Changes; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Hyperthermia; Heat Stress Disorders
• Other Study ID Numbers: STUDY00007981; CDMRP-BA230031 (Other Grant/Funding Number: Department of Defense)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Aggregate results will be shared via publications and/or presentations. De-identified data may be shared and reviewed by the Department of Defense and as part of our Cooperative Research & Development Agreement with the United States Army Research Institute of Environmental Medicine.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No