Go to the NASA Homepage
Search >
Click to Search
Human Systems Integration Division homepageHuman Systems Integration Division homepage Organization pageOrganization page Technical Areas pageTechnical Areas page Outreach and Publications pageOutreach and Publications page Contact pageContact page
Human Systems Integration Division Homepage
Outreach & Publications Sidebar Header
Go to the Outreach & Publications pageGo to the Outreach & Publications page
Go to Awards pageGo to Awards page
Go to News pageGo to News page
Go to Factsheets pageGo to Factsheets page
Go to Multimedia pageGo to Multimedia page
Go to Human Factors 101 pageGo to Human Factors 101 page
What is Human System Integration? Website
Publication Header
An at-home evaluation of a light intervention to mitigate sleep inertia symptoms  (2023)
Abstract Header
Objectives: Under laboratory settings, light exposure upon waking at night improves sleep inertia symptoms. We investigated whether a field-deployable light source would mitigate sleep inertia in a real-world setting.

Methods: Thirty-six participants (18 female; 26.6 years ± 6.1) completed an at-home, within-subject, randomized crossover study. Participants were awoken 45 minutes after bedtime and wore light-emitting glasses with the light either on (light condition) or off (control). A visual 5-minute psychomotor vigilance task, Karolinska sleepiness scale, alertness and mood scales, and a 3-minute auditory/verbal descending subtraction task were performed at 2, 12, 22, and 32 minutes after awakening. Participants then went back to sleep and were awoken after 45 minutes for the opposite condition. A series of mixed-effect models were performed with fixed effects of test bout, condition, test bout × condition, a random effect of the participant, and relevant covariates.

Results: Participants rated themselves as more alert (p = .01) and energetic (p = .001) in the light condition compared to the control condition. There was no effect of condition for descending subtraction task outcomes when including all participants, but there was a significant improvement in descending subtraction task total responses in the light condition in the subset of participants waking from N3 (p = .03). There was a significant effect of condition for psychomotor vigilance task outcomes, with faster responses (p < .001) and fewer lapses (p < .001) in the control condition.

Conclusions: Our findings suggest that light modestly improves self-rated alertness and energy after waking at home regardless of sleep stage, with lower aggression and improvements to working memory only after waking from N3. Contrary to laboratory studies, we did not observe improved performance on the psychomotor vigilance task. Future studies should include measures of visual acuity and comfort to assess the feasibility of interventions in real-world settings.
Private Investigators Header
Authors Header
Groups Header
Keywords Header
Cognitive, Countermeasure, Inertia, Intervention, Light, On-call, performance, Postawakening, Shift, Sleep, Sleep-wake, transition, work
References Header
Sleep Health, (online publication ahead of print)
Download Header
Go to the First Gov Homepage
Go to the NASA - National Aeronautics and Space Administration Homepage
Curator: Phil So
NASA Official: Jessica Nowinski
Last Updated: August 15, 2019