Alertness

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Alertness is a state of active attention characterized by high sensory awareness. Someone who is alert is vigilant and promptly meets danger or emergency, or is quick to perceive and act. Alertness is a psychological and physiological state.

Contents

Lack of alertness is a symptom of a number of conditions, including narcolepsy, attention deficit disorder, chronic fatigue syndrome, depression, Addison's disease, and sleep deprivation. Pronounced lack of alertness is an altered level of consciousness. States with low levels of alertness include drowsiness.

The word is formed from "alert", which comes from the Italian all'erta (on the watch, literally: on the height; 1618).[ citation needed ]

Wakefulness refers mainly to differences between the sleep and waking states; vigilance refers to sustained alertness and concentration. Both terms are sometimes used synonymously with alertness.

Importance and difficulty

Domenico Tintoretto, Allegory of Vigilance Allegory of Vigilance by Domenico Tintoretto.jpg
Domenico Tintoretto, Allegory of Vigilance

People who have to be alert during their jobs, such as air traffic controllers or pilots, often face challenges maintaining their alertness. Research shows that for people "...engaged in attention-intensive and monotonous tasks, retaining a constant level of alertness is rare if not impossible." If people employed in safety-related or transportation jobs have lapses in alertness, this "may lead to severe consequences in occupations ranging from air traffic control to monitoring of nuclear power plants." [1]

Neurobiological pathways

Neurotransmitters that can initiate, promote, or enhance wakefulness or alertness include serotonin, (nor)epinephrine, dopamine (e.g. blockade of dopamine reuptake), glutamate, histamine, and acetylcholine. Neuromodulators that can do so include the neuropeptide orexin. Similarly inhibition or reduction of mechanisms causing sleepiness, or drowsiness such as certain cytokines and adenosine (as with caffeine) may also increase perceived wakefulness and thus alertness.[ ambiguous ] [2] [3] [4]

Wakefulness depends on the coordinated effort of multiple brain areas. These are affected by neurotransmitters and other factors. [3] Many Neurotransmitters are in effect to experience wakefulness to include GABA, Acetylcholine, Adenosine, Serotonin, Norepinephrine, Histamine, and Dopamine. [5] There is not an isolated neurotransmitter that alone is responsible for the sensation of wakefulness. However, it is known that many transmitters are used together to cause this effect. [5] [6] Research to map the wakefulness circuitry is ongoing. [6]

Beta power has been used as an indicator of cortical arousal or alertness by several studies.[ further explanation needed ] [7] A study also measured alertness with EEG data.[ further explanation needed ] [8]

Additional information can be found on the neurobiology, neuroscience, brain, behavioral neuroscience, and neurotransmitter pages.

Drugs used to increase alertness

The stimulant and adenosine receptor antagonist caffeine is widely used to increase alertness or wakefulness and improve mood or performance. People typically self-administer it in the form of drinks like green tea (where it is present alongside the l-theanine), energy drinks (often containing sugar/sugar-substitutes), or coffee (which contains various polyphenols). The chemicals that accompany caffeine in these preparations can potentially alter the alertness-promoting effects of caffeine. [9] Caffeine is the world's most consumed stimulant drug. [10]

Various natural biochemicals and herbs may have similar anti-fatigue effects, such as rhodiola rosea. [11] Various psychostimulants like bromantane have also been investigated as potential treatments for conditions where fatigue is a primary symptom. [12] The alkaloids theacrine and methylliberine are structurally similar to caffeine and preliminary research supports their pro-alertness effects. [13]

During the Second World War, U.S. soldiers and aviators were given benzedrine, an amphetamine drug, to increase their alertness during long periods on duty. While air force pilots[ where? ] are able to use the drug to remain awake during combat flights, the use of amphetamines by commercial airline pilots is forbidden.[ where? ][ citation needed ] British troops used 72 million amphetamine tablets in the second world war [14] and the Royal Air Force used so many that "Methedrine won the Battle of Britain" according to one report. [15] [ attribution needed ] American bomber pilots used amphetamines ("go pills") to stay awake during long missions. The Tarnak Farm incident, in which an American F-16 pilot killed several friendly Canadian soldiers on the ground, was blamed by the pilot on his use of amphetamine. A nonjudicial hearing rejected the pilot's claim.

Amphetamine is a common study aid among college and high-school students. [16] Amphetamine increases energy levels, concentration, and motivation, allowing students to study for an extended period of time.[ citation needed ] These drugs are often acquired through diverted prescriptions of medication used to treat ADHD, acquired from fellow students, rather than illicitly produced drugs. [17] Cocaine is also used to increase alertness, [18] and is present in coca tea. [19]

The eugeroic modafinil has recently gained popularity with the US Military [20] [ vague ] and other militaries.

Other approaches for increasing alertness

Beyond good sleep, physical activity, and healthy diet, a review suggests odours, music, and extrinsic motivation may increase alertness or decrease mental fatigue. [21] Short rest periods and adjustments to lighting (level and type of) may also be useful. [22] Various types of neurostimulation are being researched, [23] [ further explanation needed ] as is the microbiome and related interventions. [2]

Alertness after waking

A study suggests non-genetic determinants of alertness upon waking up from sleep are: [24] [25]

The baseline of daily alertness[ clarification needed ] is related to the quality of their[ clarification needed ] sleep (currently[ may be outdated as of July 2023 ] measured only by self-reported quality), positive emotional state (specifically self-report happiness), and age. [25] There are genes that enable people to be apparently healthy and alert with little sleep. However, twin-pair analyses indicate that the genetic contribution to daytime alertness is small. [25] Other factors such as natural light exposure [25] and synchronicity with the circadian rhythm may matter as well.

Behavioral ecology

Vigilance is important for animals so that they may watch out for predators. Typically a reduction in alertness is observed in animals that live in larger groups. Studies on vigilance have been conducted on various animals including the scaly-breasted munia. [27]

See also

Related Research Articles

<span class="mw-page-title-main">Amphetamine</span> Central nervous system stimulant

Amphetamine is a central nervous system (CNS) stimulant that is used in the treatment of attention deficit hyperactivity disorder (ADHD), narcolepsy, and obesity. Amphetamine was discovered as a chemical in 1887 by Lazăr Edeleanu, and then as a drug in the late 1920s. It exists as two enantiomers: levoamphetamine and dextroamphetamine. Amphetamine properly refers to a specific chemical, the racemic free base, which is equal parts of the two enantiomers in their pure amine forms. The term is frequently used informally to refer to any combination of the enantiomers, or to either of them alone. Historically, it has been used to treat nasal congestion and depression. Amphetamine is also used as an athletic performance enhancer and cognitive enhancer, and recreationally as an aphrodisiac and euphoriant. It is a prescription drug in many countries, and unauthorized possession and distribution of amphetamine are often tightly controlled due to the significant health risks associated with recreational use.

<span class="mw-page-title-main">Caffeine</span> Central nervous system stimulant

Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class and is the most commonly consumed psychoactive substance globally. It is mainly used for its eugeroic, ergogenic, or nootropic properties. Caffeine acts by blocking binding of adenosine at a number of adenosine receptor types, inhibiting the centrally depressant effects of adenosine and enhancing the release of acetylcholine. Caffeine has a three-dimensional structure similar to that of adenosine, which allows it to bind and block its receptors. Caffeine also increases cyclic AMP levels through nonselective inhibition of phosphodiesterase, increases calcium release from intracellular stores, and antagonises GABA receptors, although these mechanisms typically occur at concentrations beyond usual human consumption.

<span class="mw-page-title-main">Modafinil</span> Eugeroic medication

Modafinil, sold under the brand name Provigil among others, is a wakefulness-promoting medication used primarily to treat narcolepsy, a sleep disorder characterized by excessive daytime sleepiness and sudden sleep attacks. Modafinil is also approved for stimulating wakefulness in people with sleep apnea and shift work sleep disorder. It is taken by mouth. Modafinil is not approved by the US Food and Drug Administration (FDA) for use in people under 17 years old.

<span class="mw-page-title-main">Recreational drug use</span> Use of drugs with the primary intention to alter the state of consciousness

Recreational drug use is the use of one or more psychoactive drugs to induce an altered state of consciousness, either for pleasure or for some other casual purpose or pastime. When a psychoactive drug enters the user's body, it induces an intoxicating effect. Recreational drugs are commonly divided into three categories: depressants, stimulants, and hallucinogens.

<span class="mw-page-title-main">Stimulant</span> Drug that increases activity of central nervous system

Stimulants are a class of drugs that increase the activity of the brain. They are used for various purposes, such as enhancing alertness, attention, motivation, cognition, mood, and physical performance. Some of the most common stimulants are caffeine, nicotine, amphetamines, cocaine, methylphenidate, and modafinil.

<span class="mw-page-title-main">Dextroamphetamine</span> CNS stimulant and isomer of amphetamine

Dextroamphetamine (INN:dexamfetamine) is a potent central nervous system (CNS) stimulant and enantiomer of amphetamine that is prescribed for the treatment of attention deficit hyperactivity disorder (ADHD), narcolepsy, and the negative symptoms of schizophrenia. It is also used as an athletic performance and cognitive enhancer, and recreationally as an aphrodisiac and euphoriant. Dextroamphetamine is generally regarded as the prototypical stimulant.

<span class="mw-page-title-main">Adderall</span> Drug mixture used mainly to treat ADHD and narcolepsy

Adderall and Mydayis are trade names for a combination drug containing four salts of amphetamine. The mixture is composed of equal parts racemic amphetamine and dextroamphetamine, which produces a (3:1) ratio between dextroamphetamine and levoamphetamine, the two enantiomers of amphetamine. Both enantiomers are stimulants, but differ enough to give Adderall an effects profile distinct from those of racemic amphetamine or dextroamphetamine, which are marketed as Evekeo and Dexedrine/Zenzedi, respectively. Adderall is used in the treatment of attention deficit hyperactivity disorder (ADHD) and narcolepsy. It is also used illicitly as an athletic performance enhancer, cognitive enhancer, appetite suppressant, and recreationally as a euphoriant. It is a central nervous system (CNS) stimulant of the phenethylamine class.

<span class="mw-page-title-main">Nootropic</span> Compound intended to improve cognitive function

Nootropics, colloquially brain supplements, smart drugs and cognitive enhancers, are natural, semisynthetic or synthetic compounds which purportedly improve cognitive functions, such as executive functions, attention or memory.

A microsleep is a sudden temporary episode of sleep or drowsiness which may last for a few seconds where an individual fails to respond to some arbitrary sensory input and becomes unconscious. Episodes of microsleep occur when an individual loses and regains awareness after a brief lapse in consciousness, often without warning, or when there are sudden shifts between states of wakefulness and sleep. In behavioural terms, MSs may manifest as droopy eyes, slow eyelid-closure, and head nodding. In electrical terms, microsleeps are often classified as a shift in electroencephalography (EEG) during which 4–7 Hz activity replaces the waking 8–13 Hz background rhythm.

Sleep inertia is a physiological state of impaired cognitive and sensory-motor performance that is present immediately after awakening. It persists during the transition of sleep to wakefulness, where an individual will experience feelings of drowsiness, disorientation and a decline in motor dexterity. Impairment from sleep inertia may take several hours to dissipate. In the majority of cases, morning sleep inertia is experienced for 15 to 30 minutes after waking.

<span class="mw-page-title-main">Armodafinil</span> Eugeroic medication

Armodafinil, sold under the brand name Nuvigil, is a wakefulness-promoting medication which is used to treat excessive daytime sleepiness associated with obstructive sleep apnea, narcolepsy, and shift work disorder. It is also used off-label for certain other indications. The drug is taken by mouth.

Performance-enhancing substances, also known as performance-enhancing drugs (PEDs), are substances that are used to improve any form of activity performance in humans.

<span class="mw-page-title-main">Lisdexamfetamine</span> Central nervous system stimulant prodrug

Lisdexamfetamine, sold under the brand names Vyvanse and Elvanse among others, is a stimulant medication that is used to treat attention deficit hyperactivity disorder (ADHD) in children and adults and for moderate-to-severe binge eating disorder in adults. Lisdexamfetamine is taken by mouth. Its effects generally begin within two hours and last for up to 14 hours.

<span class="mw-page-title-main">Norepinephrine</span> Catecholamine hormone and neurotransmitter

Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as a hormone, neurotransmitter and neuromodulator. The name "noradrenaline" is more commonly used in the United Kingdom, whereas "norepinephrine" is usually preferred in the United States. "Norepinephrine" is also the international nonproprietary name given to the drug. Regardless of which name is used for the substance itself, parts of the body that produce or are affected by it are referred to as noradrenergic.

<span class="mw-page-title-main">Monoamine releasing agent</span> Class of compounds

A monoamine releasing agent (MRA), or simply monoamine releaser, is a drug that induces the release of a monoamine neurotransmitter from the presynaptic neuron into the synapse, leading to an increase in the extracellular concentrations of the neurotransmitter. Many drugs induce their effects in the body and/or brain via the release of monoamine neurotransmitters, e.g., trace amines, many substituted amphetamines, and related compounds.

<span class="mw-page-title-main">Eugeroic</span> Drug for wakefulness and alertness

Eugeroics, also known as wakefulness-promoting agents and wakefulness-promoting drugs, are a class of drugs that promote wakefulness and alertness. They are medically indicated for the treatment of certain sleep disorders including excessive daytime sleepiness (EDS) in narcolepsy or obstructive sleep apnea (OSA). Eugeroics are also often prescribed off-label for the treatment of EDS in idiopathic hypersomnia. In contrast to classical psychostimulants, such as methylphenidate and amphetamine, which are also used in the treatment of these disorders, eugeroics typically do not produce marked euphoria, and, consequently, have a lower addictive potential.

Idiopathic hypersomnia(IH) is a neurological disorder which is characterized primarily by excessive sleep and excessive daytime sleepiness (EDS). Idiopathic hypersomnia was first described by Bedrich Roth in 1976, and it can be divided into two forms: polysymptomatic and monosymptomatic. The condition typically becomes evident in early adulthood and most patients diagnosed with IH will have had the disorder for many years prior to their diagnosis. As of August 2021, an FDA-approved medication exists for IH called Xywav, which is oral solution of calcium, magnesium, potassium, and sodium oxybates; in addition to several off-label treatments (primarily FDA-approved narcolepsy medications).

<span class="mw-page-title-main">Psychoactive drug</span> Chemical substance that alters nervous system function

A psychoactive drug, mind-altering drug, or consciousness-altering drug is a chemical substance that changes brain function and results in alterations in perception, mood, consciousness, cognition, or behavior. The term psychotropic drug is often used interchangeably, while some sources present narrower definitions. These substances may be used medically; recreationally; to purposefully improve performance or alter one's consciousness; as entheogens for ritual, spiritual, or shamanic purposes; or for research, including psychedelic therapy. Some categories of psychoactive drugs, which have therapeutic value, are prescribed by physicians and other healthcare practitioners. Examples include anesthetics, analgesics, anticonvulsant and antiparkinsonian drugs as well as medications used to treat neuropsychiatric disorders, such as antidepressants, anxiolytics, antipsychotics, and stimulant medications. Some psychoactive substances may be used in the detoxification and rehabilitation programs for persons dependent on or addicted to other psychoactive drugs.

Neuroenhancement or cognitive enhancement is the experimental use of pharmacological or non-pharmacological methods intended to improve cognitive and affective abilities in healthy people who do not have a mental illness. Agents or methods of neuroenhancement are intended to affect cognitive, social, psychological, mood, or motor benefits beyond normal functioning.

Central nervous system fatigue, or central fatigue, is a form of fatigue that is associated with changes in the synaptic concentration of neurotransmitters within the central nervous system which affects exercise performance and muscle function and cannot be explained by peripheral factors that affect muscle function. In healthy individuals, central fatigue can occur from prolonged exercise and is associated with neurochemical changes in the brain, involving serotonin (5-HT), noradrenaline, and dopamine. The roles of dopamine, noradrenaline, and serotonin in CNS fatigue are unclear, as pharmacological manipulation of these systems has yielded mixed results. Central fatigue plays an important role in endurance sports and also highlights the importance of proper nutrition in endurance athletes.

References

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  2. 1 2 Haarhuis, J.E.; Kardinaal, A.; Kortman, G.A.M. (3 August 2022). "Probiotics, prebiotics and postbiotics for better sleep quality: a narrative review". Beneficial Microbes. 13 (3): 169–182. doi: 10.3920/BM2021.0122 . PMID   35815493. S2CID   250423761.
  3. 1 2 Miller, Diane B.; O'Callaghan, James P. (October 2006). "The pharmacology of wakefulness". Metabolism. 55 (10 Suppl 2): S13–S19. doi:10.1016/j.metabol.2006.07.007. PMID   16979420.
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  6. 1 2 Grady, Fillan S.; Boes, Aaron D.; Geerling, Joel C. (2022). "A Century Searching for the Neurons Necessary for Wakefulness". Frontiers in Neuroscience. 16: 930514. doi: 10.3389/fnins.2022.930514 . ISSN   1662-4548. PMC   9344068 . PMID   35928009.
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  14. ↑ Mondenard De Monie, Jean-Pierre (2000). Dopage: l'imposture des performances: mensonges et vérités sur l'école de la triche. Chiron éd. ISBN   978-2-7027-0639-8. OCLC   997463239.
  15. ↑ Grant, D.N.W.; Air Force, UK, 1944
  16. ↑ Twohey, Megan (2006-03-25). "Pills become an addictive study aid". JS Online. Archived from the original on 2007-08-15. Retrieved 2007-12-02.
  17. ↑ The Illicit Market for ADHD Prescription Drugs in Queensland (PDF). Queensland Crime and Misconduct Commission. April 2002. Archived from the original (PDF) on 2009-05-15. Retrieved 2008-01-13.
  18. ↑ "Cocaine use rising among Hawaii workers, job applicants, lab says". Pacific Business News. 4 July 2014.
  19. ↑ Chen, Cheng; Lin, Ligen (2019). "Alkaloids in Diet". Handbook of Dietary Phytochemicals. Springer. pp. 1–35. doi:10.1007/978-981-13-1745-3_36-1. ISBN   978-981-13-1745-3. S2CID   214115630.
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  26. ↑
  27. ↑ Roche, Erin A.; Brown, Charles R. (December 2013). "Among-individual variation in vigilance at the nest in colonial Cliff Swallows". The Wilson Journal of Ornithology. 125 (4): 685–695. doi:10.1676/12-196.1. ISSN   1559-4491. S2CID   13865609.
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