Sleep Deprivation and Sleep Disorders
Introduction[edit | edit source]
Sleep is a universal experience and it is essential for general health and survival.[1][2] It has multiple functions and is important for cognition (ie the ability to think clearly, to be vigilant, alert and to pay attention) as well as memory consolidation and emotional regulation.[2] Poor quality sleep, as well as sleep loss or poorly regulated sleep can have a negative impact on physical and mental function.[1] It can cause sleepiness, a decline in performance, as well as affect psychological and physical functions, such as memory, learning, metabolism and immunity.[3]
Impact of Sleep Deprivation on EEGs[edit | edit source]
Sleep research has progressed over the last few decades due to the examination of electroencephalogram (EEG) patterns that occur during sleep. This research has enabled researchers to classify sleep into various stages, and thus, provided a basis for exploring sleep abnormalities and the relationship between health and sleep.[2]
Various changes in patterns are also evident on waking EEGs following periods of sleep deprivation. A study by Ferriera et al (2006) demonstrated that just one night of sleep deprivation resulted in specific electrophysiological changes on EEG, including increases in relative delta and theta power, as well as absolute alpha and beta power reduction.[4]
Certain deteriorations in performance have also been noted during brief periods (lasting from between 2 and 20 seconds) on waking EEGs - at these points, the EEGs showed slow termed microwaves, which are known as ‘micro-sleeps’. Such momentary lapses are highly significant, when considering the impact they can have on workers.[1] Early concerns about public/occupational health and sleep disorders were first noted when industrial disasters such as the Exxon Valdex oil spill of 1989 were linked to sleep loss.[2] Similarly, health professional who do shift work, have been found to be at increased risk for occupational hazards, as well as car accidents when driving home from work.[1]
Impact of Sleep Deprivation on Sleepiness[edit | edit source]
A dose related increase in sleepiness, as well as a reduction in performance, occurs after sleep loss.[1][3] This is highlighted in a number of ways, including physiological measures such as sleep latency (ie the onset time to sleep), subjective reporting of sleepiness and standardised behavioral testing such as reaction time. Differences are noted in both partial and complete sleep loss, as well as when sleep is broken up or “waking activities” are shifted to night-time hours (ie shift work).[1]
Sleep debt, which accumulates when sleep is restricted, cannot be repaid.[1] However, individuals do tend to sleep for longer periods after periods of sleep deprivation or restriction and some studies highlight the benefits of extended sleep on improving performance.[3][5]
Caffeine[edit | edit source]
The most common psychoactive substance is caffeine.[6] It is used to help with fatigue, to enhance performance and to prevent apnea in premature infants.[6] However, in a recent systematic review, it has been shown to prolong sleep latency, reduce sleep length and efficiency and also to negatively impact an individual's perceived sleep quality.[6]
It has been found that adenosine (a governing sleep factor) has an intrinsic relationship with caffeine. Their similar structure enables caffeine to bind to adenosine receptors. This blocks the adenosine receptors’ function and creates a sense of wakefulness.[1] However, the cumulative impact of adenosine will always increase, regardless of extrinsic factors such as caffeine. Thus, people will eventually experience a sudden increase in their level of fatigue once the effects from caffeine wear off.[1]
The effect of caffeine varies between people. Older adults’ sleep may be more sensitive to caffeine[6] and some genetic studies have shown that certain people, particularly those carrying the cYP1a2 gene, may be more likely to experience sleep disruption secondary to caffeine intake.[6][1] It is thought that an over-reliance on caffeine may be one of the biggest causes of ineffective rest in healthcare workers. Thus, timing the consumption of caffeine might be a way to enhance sleep quality, as well as ensure better regulation of sleep; restricting caffeine after 2pm could be once such strategy.[1]
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 Whelehan, D. Sleep Deprivation and Sleep Disorder Course. Physioplus. 2020.
- ↑ 2.0 2.1 2.2 2.3 Worley SL. The Extraordinary Importance of Sleep: The Detrimental Effects of Inadequate Sleep on Health and Public Safety Drive an Explosion of Sleep Research. P T. 2018;43(12):758-763.
- ↑ 3.0 3.1 3.2 Kitamura S, Katayose Y, Nakazaki K, et al. Estimating individual optimal sleep duration and potential sleep debt. Sci Rep. 2016;6:35812.
- ↑ Ferreira C, Deslandes A, Moraes H, Cagy M, Pompeu F, Basile LF et al . Electroencephalographic changes after one night of sleep deprivation. Arq. Neuro-Psiquiatr. 2006; 64(2b): 388-393.
- ↑ Arnal PJ, Sauvet F, Leger D, van Beers P, Bayon V, Bougard C et al. Benefits of Sleep Extension on Sustained Attention and Sleep Pressure Before and During Total Sleep Deprivation and Recovery. Sleep. 2015; 38(12): 1935-43.
- ↑ 6.0 6.1 6.2 6.3 6.4 Clark I, Landolt HP. Coffee, caffeine, and sleep: A systematic review of epidemiological studies and randomized controlled trials. Sleep Medicine Reviews. 2017; 31: 70-8.
