How the study worked
In the early 1990s, NASA’s Ames Research Center studied whether a planned rest period in the cockpit could help manage fatigue on long-haul flights. The 12 crew members in the rest group were given a 40-minute rest opportunity during the quiet cruise phase. The 9 crew members in the control group carried on as usual.[1]
The researchers measured brain wave and eye movement activity, reaction time and attention, and the pilots’ own ratings of fatigue.[1]
Results
The nap was linked to better physiological alertness and performance, and the benefit lasted into the critical phases of the flight: descent and landing. It did not affect the pilots’ sleep during layovers or their accumulated sleep debt.[1]
The widely quoted numbers come from a 1995 summary. During the 40-minute rest opportunity, pilots slept an average of 26 minutes. Their performance on a reaction time and attention test improved by 34%, and their physiological alertness by 54%.[2]
What it means for the workplace
The researchers stressed that a nap should be planned and should account for two possible side effects: sleep inertia, the short-lived grogginess after waking, and the effect on later sleep.[2] A short nap at a set time in a set place works best.
Sources
- Rosekind MR, Graeber RC, Dinges DF et al. Crew Factors in Flight Operations IX: Effects of Planned Cockpit Rest on Crew Performance and Alertness in Long-Haul Operations. NASA Technical Memorandum 108839. NASA Ames Research Center, 1994. ntrs.nasa.gov/citations/19950006379 (opens in a new window)
- Rosekind MR, Smith RM, Miller DL et al. Alertness management: strategic naps in operational settings. Journal of Sleep Research. 1995;4(Suppl 2):62–66.
