Sleep and Sleep Hygiene in an Occupational Health & Safety Context Glenn Legault Ph.D. Center for Research in Occupational Safety and Health, Laurentian University Nov. 12, 2014
Overview: Sleep what is it? How is sleep measured? How does sleep disruption occur? Sleep pathology Circadian changes due to work What happens when our sleep is disrupted? Fatigue in the workplace Questions
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The study of human sleep: Sleep logs Sleep quality indices Epworth, Stanford Sleepiness Scale, Pittsburgh Sleep Quality Index etc. Actigraphy Polysomnography Electroencephalogram (EEG) Electrooculogram (EOG) Electromyogram (EMG) Airflow measures Oxygen saturation Posture indicators
Wakefulness
Slow wave sleep
Rapid eye movement sleep
Wakeful, eyes open: REM Sleep:
Slow Wave Sleep -Growth Hormone secreted -Declarative memories formed I am I know that I live in
REM Sleep -Large amount of metabolic energy being expended -Procedural memories consolidated -typing -driving
Role(s) of Sleep: Restorative function (No evidence of ATP production or protein synthesis) Behavioural adaptation (Why does sleep rebound occur?) Sentinel function (Rats have REM when caged near cats) Forgetting (Unlikely that you will recall this lecture if woken from your dream tonight)
Role(s) of Sleep (Cont): Immune function (Terminally sleep deprived rats died of septicemia; however, when another group was given prophylactic antibiotics, they also died) Learning (tricyclic antidepressants decrease REM sleep; however, there is no evidence of cognitive deficits in long-term users)
Sleep Disorders: Sleep Apnea. Restless Leg Syndrome. Periodic Limb Movement Disorder. REM Behaviour Disorder. Narcolepsy Insomnia (?????)
Sleep Apnea: Up to 25 % of the population. 2-3 times greater risk for men. For pregnant women, risk increases: Increased weight Throat swelling Sleep deprivation
Anatomical correlates Narrowed or collapsible pharynx Resistance to inspiratory air flow Decreased muscle tone Blood oxygen saturation, Blood carbon dioxide level may.
Causes Excess body weight Alcohol use Tobacco use Nasal congestion Treatment Control weight Control hypertension Continuous Positive Airway Pressure (CPAP)
Restless Legs Syndrome: Up to 15 % of the population Any age can be affected; most sufferers have first experience by age of 20
Causes Genetic Iron deficiency Brain lesions Pregnancy Kidney disease Medications
Periodic Limb Movement Disorder: Up to 35 % of people over age 60 have PLMD. Most do not know they have PLMD Hair wearing off legs Hot or cold feet Bed partners will complain of being kicked Sheets are dishevelled on awakening
Causes: Brain and spinal cord dysfunction Circulatory problems Kidney disease Metabolic disorders Arthritis
REM Behaviour Disorder: Mostly affects elderly men. Normal muscle paralysis during REM sleep is blocked allowing the patient to act out dreams Harmful or potentially harmful sleep movements that disturb sleep Possible predictor of Parkinson s Disease
Causes: Largely unknown. Possibly due to Tumour in the brainstem MS Shy-Drager syndrome
Narcolepsy: Affects about 1 in 1000 (same as MS) Characterized by: Excessive daytime sleepiness Cataplexy Sleep paralysis Hallucinations in sleep
Symptoms show when REM sleep intrudes into normal wake times. On going to bed, narcoleptics enter REM very quickly. Restorative deep sleep (SWS) is reduced leaving patients chronically sleep deprived. Causes: Genetic Trauma Viral infections
Insomnia: Better to think of this as a symptom not a condition. Continuum of Insomnia: Normal Abnormal Chronic Cannot get to sleep Cannot stay asleep Do not get enough sleep
Perhaps the best way to understand why sleep is important is to realize what happens when we don t get enough sleep: Concentration decreases Decision making ability declines Irritability and frustration increase Motor functions are diminished Speech is impaired Increased numbers of car accidents More workplace accidents Our ability to fight off illness and disease decreases Mental and physical illness increases/worsens Aging processes are speeded up
Long term sleep deprivation has potentially catastrophic effects Can lead to hallucinations and suicidal ideation. Major human disasters have been attributed to people experiencing sleep deprivation: Three Mile Island power plant accident Exxon Valdez oil spill Bhopal gas leak Challenger shuttle explosion New research on soldiers has shown that sleep deprivation leads to diminished decision making ability, constructive thinking, and moral reasoning.
Occupational Health & Safety Issues Motor vehicle collisions among medical interns Odds of a car accident after an extended shift are more than doubled from those of a normal shift (Barger et al. 2005) Visual vigilance for drivers with OSA OSA drivers have reduced vigilance and reaction times compared to controls (Tippin et al., 2009)
Sleeping or drowsiness was a factor in 3.9 % of all at fault car accidents In 18.6 % of night-time accidents In 8.3 % of running off the road accidents In 8.1 % of accidents that occurred during a trip of >150 km In 7.3 % of all accidents that had personal injuries. (Sagburg et al., 1999) After 17 19 hours of sleep deprivation vigilance, reaction time, tracking, perception or memory were decreased to the same extent as having a BAL was 0.05. With longer intervals of sleep deprivation, performance approached that of having a BAL of 0.10 (Williamson & Feyer, 2000)
Cancer prevalence Increased prevalence of breast cancer in shiftworking women. Increased prevalence of prostate cancer in shiftworking men. These results are supported by rodent model data. (Straif et al., 2007)
Thank you! Questions?