Definition of «alertness»

The state or condition of being awake, watchful and attentive.

A person's alertness can be measured by their ability to quickly respond to stimuli.
Drinking a cup of coffee in the morning can increase alertness and help you stay focused throughout the day.
Lack of sleep can impair alertness and lead to decreased cognitive function.
The lifeguard's job requires high levels of alertness to quickly respond to any potential dangers.
Parents need to maintain a level of alertness when watching their children play to ensure their safety.
Driving a car requires constant alertness to respond to changing road conditions and potential hazards.

It requires courage, wisdom, timing, focus, and an incredible sense of alertness of everything happening around you. (christianitytoday.com)
The resume of a truck driver mostly highlights the physical skills, mental alertness of the driver as well as his expertise in driving the huge vehicle safely. (template.net)
In a study funded by NASA, David Dinges, a professor at the University of Pennsylvania, and a team of researchers found that letting astronauts sleep for as little as fifteen minutes markedly improved their cognitive performance, even when the nap didn't lead to an increase in alertness or the ability to pay more attention to a boring task. (businessinsider.com)
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