Fatigue; Heat, Hyperthermia
Conditions
Brief summary
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.
Interventions
OTHER30/30 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.
OTHER30/20 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.
OTHER40/30 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.
OTHER20/12 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.
Sponsors
State University of New York at Buffalo
United States Department of Defense
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 39 Years
Healthy volunteers
Yes
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Core temperature | 180 minutes of work | Maximum gastrointestinal temperature reached during the work protocol |
| Isometric mid-thigh pull strength | 180 minutes of work | Maximum voluntary contraction strength assessed using a force plate |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Metabolic cost | 180 minutes of work | Collected expired air using a one-way mask will be analyzed using a metabolic cart to calculate metabolic heat production |
| Heart rate | 180 minutes of work | Maximum heart rate measured using a telemetry strap throughout the work protocol |
| Mean skin temperature | 180 minutes of work | Maximum skin temperature measured using buttons at four skin sites |
| Vastus lateralis electromyography | 180 minutes of work | Wireless electromyography electrodes placed lengthwise over the vastus lateralis muscle belly |
Countries
United States
Contacts
CONTACTRiana R Pryor, PhD
PRINCIPAL_INVESTIGATORRiana R Pryor, PhD
University at Buffalo
Outcome results
None listed