Fatigue in Long-Haul Operations

NCT07761611 | Not Yet Recruiting

• 2 other identifiers: STUDY00000991A2509-069-080-084046
• Study Type: interventional
• Target: 118
• Locations: 1 country
• Sites: 1

Brief Summary

The purpose of the present study is to test novel countermeasures to reduce fatigue among airline pilots during long-haul flight operations. The investigators will collect objective and subjective sleep, sleepiness, workload, and performance data from active-duty line pilots flying long-haul flight operations (\>8 hours). Data will be collected during days off prior to the trip start, during flights and layover, and during days off following the trip end.

Conditions

Alertness, Fatigue, Mood, and Performance; Calorie Restriction and Light Intervention

Keywords

fatigue; alertness; cognitive performance; light intervention; calorie restriction; aviation; psychomotor vigilance task; NASA TLX

Outcome Measures

Primary Outcomes (4)

• Vigilant Attention

  Measured using the 5-minute Psychomotor Vigilance Task (PVT); a simple reaction time test with measures that include mean reaction time, response speed (1/RT), and number of lapses (RT \> 500ms).

  minimum of 18 days, morning, afternoon, evening and top of descent of all flights

• Subjective Sleepiness

  Measured using the Karolinska Sleepiness Scale (KSS); a 9-point Likert scale with higher scores indicating higher levels of sleepiness.

  Minimum of 18 days, morning, afternoon, evening and top of descent of all flights

• Subjective Fatigue

  Measured using the Samn-Perelli fatigue scale; a 7-point Likert scale with higher scores indicating higher levels of fatigue

  minimum of 18 days, morning, afternoon, evening and top of descent of all flights

• Objective Sleep

  Measured using an accelerometer (wristwatch-like device) and light sensor to determine sleep and wake patterns and various other objective sleep metrics (e.g., sleep onset, wake after sleep onset, total sleep time).

  24 hours a day for a minimum of 18 days

Study Arms (2)

Intervention (caloric restriction and light intervention)

EXPERIMENTAL

The intervention will involve asking pilots to reduce their calorie intake during the biological night to \< 10% of their daily need and to wear blue-enriched light emitting glasses for 20 minutes following their inflight rest break before they return to the flight deck during both outbound and return flights

Behavioral: Caloric restriction; Device: Light exposure

Control

NO INTERVENTION

The control condition will involve reminding pilots about standard fatigue risk management practices that are recommended by their company.

Interventions

Caloric restriction BEHAVIORAL

To reduce calorie intake during the biological night to \< 10% of calculated daily need.

Intervention (caloric restriction and light intervention)

Light exposure DEVICE

To wear blue-enriched light emitting glasses for 20 minutes following an inflight rest break before returning to the flight deck during both outbound and return flights.

Intervention (caloric restriction and light intervention)

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• All medically qualified, active-duty pilots currently flying overnight long-haul operations are eligible to be included as participants in the study. Participants must be line pilots that spend at least 50% of their typical monthly schedule flying long-haul operations (defined at flights over eight hours induration).

You may not qualify if:

• Pilots with metabolic disorders, such as diabetes, those actively trying to lose weight or receiving GLP-1 injections, or those who indicate that they are sensitive to light will be excluded from participation. The medical monitor will review the pilot's self-reported medical conditions and medications (if applicable) prior to enrolment in the study.

Sponsors & Collaborators

• National Aeronautics and Space Administration (NASA): lead
• Civil Aerospace Medical Institute: collaborator
• Washington State University: collaborator

Study Sites (1)

NASA Ames Research Center

Mountain View, California, 94043, United States

Location

Related Publications (39)

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MeSH Terms

Conditions

Fatigue

Interventions

Caloric Restriction

Condition Hierarchy (Ancestors)

Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Diet Therapy; Nutrition Therapy; Therapeutics; Energy Intake; Diet; Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena

Central Study Contacts

Erin E Flynn-Evans, PhD, MPH

CONTACT

6502793459; erin.e.flynn-evans@nasa.gov

Nicholas G Bathurst, MA

CONTACT

6506040795; nicholas.g.bathurst@nasa.gov

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: FED
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Laboratory Director

Model Details: Participants will be randomized to receive the intervention or control. The intervention will involve asking pilots to reduce their calorie intake during the biological night to \< 10% of their daily need and to wear blue-enriched light emitting glasses for 20 minutes following their inflight rest break before they return to the flight deck during both outbound and return flights. Participants in the intervention condition will also be asked to refrain from eating during the biological night during the three pre-trip nights. The control condition will involve reminding pilots about standard fatigue risk management practices that are recommended by their company. This will be a between-subjects, rather than within-subjects study to minimize intervention spillover. Participants will collect data for two trips, with the first trip representing a baseline for each collection.

Study Record Dates

• First Submitted: July 10, 2026
• First Posted: August 12, 2026
• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): July 1, 2029
• Study Completion (Estimated): July 1, 2029
• Last Updated: August 12, 2026

Record last verified: 2026-08

Locations

US (1)