Alert state

The phrase alert state is used in more than one professional discipline.

National defence
The phrase alert state is used in milieu variously, although in a capitalized form the reference is of an indication of the state of readiness of the armed forces for military action or a State against terrorism or military attack. The term frequently used is on High Alert Examples are the DEFCON levels of the US armed forces, probably indicating some degree within DEFCON:2 to DEFCON:4, possibly DEFCON:1 classified with the words as high alert.

The British government's UK Threat Levels, probably including the highest three levels of five, these being classified as substantial,severe and critical. Both highest positions within the classification are synonymous with red alert. All these rely on an understanding of the word alert, which is also originally relevant to a type of military activity, within the earliest recorded usage.

Psychology
In the context of the Mental status examination,the state of consciousness of an alert person is classified apart from either lethargic or hyper-alert, elsewhere an alert person is capable of providing the correct information when asked their name, their present location and the date, or otherwise is able to talk normally. Altogether the relaxed and alert state of mind of the meditator is scientifically classified as brainwaves of the alpha and beta description respectively. The beta state that corresponds to the prior description is, in fact, within the range of 12 to 15 Hz (& 15–19 Hz).

Other
The phrase is in use within environmental considerations,   and also is in usage as a term of  change within a system generating electrical energy.