Effects of sleeping in a chemical protective mask on sleep quality and cognitive performance.
OBJECTIVE
We wanted to determine whether sleep is disrupted when soldiers sleep in a new chemical protective mask, the M40. Sleep quantity and quality, extent of protection provided by the mask during sleep, and next day performance were assessed.


METHODS
After several days of training, 9 male soldiers slept with and without the M40 mask on four occasions.


RESULTS
Soldiers were able to tolerate the mask for most or all of the night. However, sleep, as assessed by wrist-worn activity monitors, was significantly disturbed. Minutes (mean +/- SEM) of waking significantly increased, from 25 +/- 2.1 to 86 +/- 8.5 per night (p < 0.001), and number of awakenings rose from 8 +/- 0.6 to 20 +/- 0.9 (p < 0.0001). Soldiers reported that it took longer and was more difficult to fall asleep when wearing the mask. Errors on a choice reaction time task increased significantly and subjects reported greater fatigue and sleepiness the day after sleeping in the mask. Protection provided by the masks varied substantially among subjects and declined over the course of the study. Some soldiers were protected throughout the night but others were only protected intermittently.


CONCLUSIONS
We conclude that sleeping in the chemical protective mask should only be done when necessary, given the adverse effects on sleep and daytime function, as well as the variability of protection, of the mask.
Lieberman
H R
HR
Military Performance and Neuroscience Division, U.S. Army Research Institute of Environmental Medicine (USARIEM), Natick, MA 01760-5007, USA.
Mays
M Z
MZ
Shukitt-Hale
B
B
Chinn
K S
KS
Tharion
W J
WJ
D000328:Adult; D000339:Affect; D000395:Air Pollutants, Occupational / Q000032:analysis; D002618:Chemical Warfare; D003071:Cognition; D006801:Humans; D008297:Male; D008889:Military Personnel; D017286:Polysomnography; D011597:Psychomotor Performance; D012134:Respiratory Protective Devices / Q000009:adverse effects*; D012893:Sleep Wake Disorders / Q000209:etiology*; D011795:Surveys and Questionnaires; D013997:Time Factors
D000395:Air Pollutants, Occupational