In 1965, Randy Gardner intentionally stayed awake for 264 hours, the longest without sleep, for a high school project (a Guinness World Record then).[3
] He experienced significant deficits in concentration, motivation, perception, and higher mental processes during his sleep deprivation. However, he recovered normal cognitive functions after a few nights of sleep. The Guinness Book of World Records has withdrawn its backing of sleep deprivation category because of the associated health risks.
A meta-analysis of 29 studies evaluated the association of physically demanding work, prolonged standing, long work hours, and cumulative “fatigue score” with preterm delivery, pregnancy-induced hypertension, and small-for-gestational-age infants. Circadian disruption alters glucose tolerance, cortisol concentrations, and sympathetic tone and affects pregnancy outcome. There was a positive association between physically demanding work and pregnancy-induced hypertension, and delivery of small-for-gestational-age infants. Shift work alone was found to increase the incidence of preterm births.[10
] An increased risk of breast cancer in females who worked night shifts [odds ratio (OR) = 1.6 and relative risk (RR) = 1.36] was demonstrated in female workers[11
] and a cohort study on female nurses.[13
Dawson et al
. compared subjects’ psychomotor functions during sleep deprivation and after consumption of alcohol.[13
] After 17 hours of sustained wakefulness, the subject’s psychomotor performance decreased to a level that was equivalent to that when their blood alcohol concentration was 0.05%. By 24 hours of sustained wakefulness, performance decreased to the same extent as observed at a blood alcohol concentration of 0.10%, an alcohol level at which the driver of a motor vehicle is considered intoxicated in most states in the USA.[14
Federal Transportation Agency in USA submits that sleep deprivation is a major factor in many motor vehicle accidents.[15
] A survey conducted on emergency medicine residents indicated an increased risk of traffic accidents while driving home after a night shift.[12
] A prospective, Web based survey documented the incidence of motor vehicle crashes and near-miss incidents for 2737 interns.[18
] After an extended work shift (greater than 24 hours), the OR for a motor vehicle crash was 2.3 compared for travel home after a shorter shift, and was 5.9 for a near-miss occurrence. When there were five or more extended work shifts in a month, the risks that the intern would fall asleep while driving (OR = 2.4) or while stopped in traffic (OR = 3.7) were increased. In developed countries, a training programme may incur liability if one of their residents is injured in a traffic accident after working an extended shift.[19
Studies and meta-analyses have demonstrated that after a period of sleep deprivation such as being on-call, physicians have worse language and numeric skills, poor retention of information, and impaired short-term memory and concentration.[20
] They also observed that sleepiness has a significant negative effect on mood, with individuals demonstrating increased anger, lack of concentration, and anxiety. There are several examples of self-reported data linking the fatigue of health care personnel to medical errors. A survey of anaesthesia providers in New Zealand suggests that fatigue may have compromised patient safety with 86% of respondents reporting fatigue-related errors.[22
] Because these are self-reported data, the validity of this information and the causality of fatigue in the reported errors cannot be determined. Unfortunately, some of the older published studies suffer from design flaws such as lack of control groups, inadequate documentation of sleep state, failure to control for circadian effects, and lack of randomisation.