A dose–response study of total sleep time and the ability to maintain wakefulness

Abstract

SUMMARYThe apparent connection between sleep debt, performance decrements and workplace accidents has generated a need for feasible vigilance tests that focus on the quantification of daytime sleepiness in occupational settings. The objective of this study was to evaluate the sensitivity of the Maintenance of Wakefulness Test (MWT) to acute sleep deprivation of various doses. Eight healthy female volunteers, mean age 28.9 years (range 23-36), participated in this laboratory study. After an adaptation night, the subjects were assigned to four counterbalanced, randomly ordered night sleep conditions. These four conditions allowed for a time in bed (TIB) of 0, 2, 4 or 8 h, producing a total sleep time of 0, 113, 218 and 427 min, respectively. The ability to sustain wakefulness was measured after the TIB period at 11.00 and 17.00 hours by the MWT. Analysis of variance with repeated measures was used to study the dependence of MWT sleep latencies on the immediately prior TIB period. Both the latency of stage 1 sleep onset and the appearance of slow eye movements reduced significantly with increased sleep loss. The quantitative relationship between the previous total sleep time and the subsequent MWT sleep latencies followed an exponentially decaying function showing a high sensitivity to acute, severe night sleep loss but low sensitivity to less severe sleep restrictions. It is concluded that the MWT seems to be a sensitive method for the estimation of acute sleep deprivation. The test results appear, however, non-linearly related to the earlier sleep debt.

Correlates of Occupational Injuries for Various Jobs in Railway Workers: A Case‐Control Study

“…For sleep disorders, our finding confirms the results of some investigations which concerned truck drivers 16,18,19,33) and construction workers 34) . Sleep disorders act on fatigue, vigilance, ability in assessing or watching the work environment and work conditions 18) .…”

“…Sleep disorders act on fatigue, vigilance, ability in assessing or watching the work environment and work conditions 18) . As expected, requesting a job change also played a role in occupational injuries.…”

“…In France, the railway firm employs 184,000 workers, and its annual incidence rate of occupational injuries with sick leave is also about 4%. Preventive measures are therefore necessary to reduce the injuries, and they should concern work conditions [5][6][7] , but also training 8) , living conditions (smoking [8][9][10][11][12] , alcohol use [11][12][13][14] , physical activities 12,15) , body weight 16,17) , sleep disorders 16,18,19) , health status and disabilities 7,20) , and other risk factors such as young age 7,8,[21][22][23] , job knowledge and experience 8,21,24) , risk perception, personality and behavior [25][26][27] ). But these risk factors have been identified in few specific populations only, and it is difficult to generalize and apply the findings to other populations.…”

The role of occupational activities and work environment in occupational injury and interplay of personal factors in various age groups among Indian and French coalminers

“…In this context, the experience and job knowledge cannot eliminate the injuries if the number of demanding hazards is continuously high. Thus, prevention should focus especially on those hazards that affect working capacity of the workers and consequently the quality of task performed, alertness, vigilance, and observing numerous hazards [3,33]. Our studies found that, like occupational factors, the personal ones such as regular alcohol use, sleep disorders, altered health status, frequent psychotropic drug use, and chronic diseases (especially musculoskeletal disorders), as well as physical, seeing, hearing, and cognitive disabilities, which may affect working capacity of the workers, also played a role in the injuries.…”

Relationships of Job and Some Individual Characteristics to Occupational Injuries in Employed People: A Community‐Based Study

“…Nevertheless, certain individual factors which concern many employed people such as young age [7][8][9][10][11] , body weight 12,13) , lack of training 14) , lack of experience 9,15) , smoking 14,[16][17][18][19] , alcoholic drink consumption 18,20) , sleep disorders 11,13,[21][22][23][24][25][26] , and some disabilities 27) , have been identified as risk factors for occupational injuries. Although prevention measures are mainly concerned with the work conditions, the knowledge of jobs at risk and the related risk factors could help occupational physicians to make workers, who are exposed to higher risk, more sensitive to the injury risks during the yearly medical examination.…”