Operational Stress for Fatigue
(REP DEF Trial)

Recruiting in Palo Alto (17 mi)

Overseen byJess A Gwin Principal Investigator, PhD

Age: < 65

Sex: Any

Travel: May Be Covered

Time Reimbursement: Varies

Trial Phase: Academic

Waitlist Available

Sponsor: United States Army Research Institute of Environmental Medicine

No Placebo Group

Trial Summary

What is the purpose of this trial?This longitudinal study will examine the effects of repeated bouts of operational stress and limited recovery on integrated MPS, whole-body protein balance, iron absorption, and aerobic performance. Following baseline characterization measures, active adults (n=24) representative of normal weight phenotype (NW; n=12) and overweight phenotype (OW; n=12) will complete a 48h balance phase preceding two rounds of repeated 72h energy deficit exposure each immediately followed by a 48h recovery phase. NW cutoff will be defined ≤ 22% body fat for males and ≤ 32% body fat for females. OW cutoff will be defined as \>22% body fat for males and \>32% body fat for females. These body composition cutoffs are informed by the maximum allowable percent body fat standards outlined in current Army Regulation 600-9. Additional details for determining % body fat are outlined in the experimental procedures section of the protocol.

Eligibility Criteria

This trial is for active adults who are either of normal weight (males ≤ 22% body fat, females ≤ 32%) or overweight (males > 22%, females > 32%), based on Army Regulation standards. Participants will undergo stress tests and have their muscle protein synthesis, iron absorption, and aerobic performance measured.

Inclusion Criteria

Healthy without evidence of chronic illness or musculoskeletal injury as determined by the USARIEM Office of Medical Support and Oversight (OMSO) or home duty station medical support (HMS)

Functional exercise and/or aerobic exercise trained defined by self-report as performing ≥ 2 sessions/wk for previous 6 months

Willing to refrain from alcohol, smoking any nicotine product, vaping, chewing tobacco, caffeine not provided in the study, and dietary supplement use throughout the dietary interventions

+4 more

Exclusion Criteria

I have injuries that affect my ability to exercise.

History of complications with lidocaine or similar local anesthetic analogue

Claustrophobia or discomfort related to having enclosed equipment around the head

+8 more

Participant Groups

The study looks at how repeated operational stress with limited recovery affects the body's ability to synthesize proteins, absorb iron, and perform aerobically. It involves two cycles of a strict regimen: a stressful energy deficit period followed by short recovery.

2Treatment groups

Experimental Treatment

Active Control

Group I: Active adults representative of overweight phenotypeExperimental Treatment1 Intervention

Active adults representative of overweight phenotype will complete a 48h balance phase followed by two rounds of repeated 72h energy deficit exposure, each immediately followed by a 48h recovery phase.

Group II: Active adults representative of normal weight phenotypeActive Control1 Intervention

Active adults representative of normal weight phenotype will complete a 48h balance phase followed by two rounds of repeated 72h energy deficit exposure, each immediately followed by a 48h recovery phase.