Alertness

Alertness is being very aware of what is happening around you. When someone is alert, they notice things quickly and can react fast if something unexpected happens. This helps people stay safe and make good decisions.

Many health conditions can make it hard to stay alert. For example, people with conditions like narcolepsy, attention deficit hyperactivity disorder, chronic fatigue syndrome, depression, Addison's disease, or sleep deprivation may feel sleepy or less aware of their surroundings. When alertness is very low, it can change how a person thinks and feels.

Alertness comes from the word "alert," which started in Italian as all'erta, meaning "on the watch." Being awake, or wakefulness, is different from alertness, though they are related. Vigilance, or vigilance, means staying alert for a long time, and concentration is focusing on one thing for a while. All these ideas help people stay aware and ready to act.

Importance and difficulty

Some jobs, like being an air traffic controller or a pilot, need people to stay very alert. It's hard to stay alert all the time, especially when the work is boring or needs a lot of focus. If someone in these important jobs isn't alert, it can cause big problems, like in air traffic control or watching over nuclear power plants.

Neurobiological pathways

See also: Stimulant § Mechanisms of action, and Neuroenhancement

Neurotransmitters are special chemicals in the brain that help us stay awake and alert. Some of these include serotonin, (nor)epinephrine, dopamine, glutamate, histamine, and acetylcholine. Other brain chemicals, called neuromodulators, like the neuropeptide orexin, also help us stay awake.

Staying awake and alert depends on many parts of the brain working together. These parts are influenced by the brain chemicals mentioned above. There isn’t just one brain chemical that makes us feel awake — many work together. Scientists are still studying exactly how this system works.

Beta power and EEG data are tools scientists use to measure how alert the brain is.

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

Drugs used to increase alertness

Caffeine is a common way people try to stay alert and awake. It is found in drinks like green tea, energy drinks, and coffee. Caffeine helps improve mood and performance, but other chemicals in these drinks can change how well it works.

During World War II, some soldiers and pilots used special drugs to stay awake during long missions. Today, some students use certain medications to help them study longer. Other substances are also used to stay alert, but these can be dangerous.

Other approaches for increasing alertness

Besides getting good sleep, staying active, and eating a healthy diet, there are other ways to feel more alert. Things like pleasant smells, listening to music, and having a reason to stay focused motivation might help. Taking short breaks and changing how bright or what kind of light you have can also be useful. Scientists are studying different types of neurostimulation, as well as looking at the microbiome and ways to support it.

Alertness after waking

Being alert when you wake up depends on a few things. How much and how well you slept the night before, how active you were the day before, and eating a breakfast with lots of carbohydrates can all help. Having a lower rise in blood sugar after breakfast also helps, and this can be changed by choosing the right foods.

Your overall alertness during the day is linked to how well you sleep, feeling happy, and your age. Some people have genes that let them stay alert with less sleep, but for most people, genes don’t play a big role. Getting natural light and matching your schedule with your body’s natural rhythm also matter.

Behavioral ecology

Animals need to stay alert to watch for danger, like predators that might want to hurt them. When animals are in larger groups, they often don’t need to be as alert because there are more eyes to spot danger. Scientists have studied this behavior in many animals, including the scaly-breasted munia.