Lethargy is a state of tiredness, weariness, fatigue, or lack of energy. It can be accompanied by depression, decreased motivation, or apathy. Lethargy can be a normal response to boredom, inadequate sleep, overexertion, overworking, stress, lack of exercise, or a symptom of a disorder. When part of a normal response, lethargy often resolves with rest, adequate sleep, decreased stress, and good nutrition.[21][22]

If he can maintain his concentration, Goetz intends to continue his own research into understanding the nature of boredom. He wants to measure physiological signs of arousal, which could one day add a new component to wearable health trackers. He’s also interested in investigating whether specific boredom types correspond to different age levels and cultures. “There are many important questions to be answered related to the boredom types,” he says.

^ Vodanovich, Stephen J. (November 2003) "Psychometric Measures of Boredom: A Review of the Literature" The Journal of Psychology. 137:6 p. 569 "Indeed, a shortcoming of the boredom literature is the absence of a coherent, universally accepted definition. The lack of an agreed-upon definition of boredom has limited the measurement of the construct and partly accounts for the existence of diverse approaches to assessing various subsets of boredom."
Erich Fromm and other thinkers of critical theory speak of boredom as a common psychological response to industrial society, where people are required to engage in alienated labor. According to Fromm, boredom is "perhaps the most important source of aggression and destructiveness today." For Fromm, the search for thrills and novelty that characterizes consumer culture are not solutions to boredom, but mere distractions from boredom which, he argues, continues unconsciously.[29] Above and beyond taste and character, the universal case of boredom consists in any instance of waiting, as Heidegger noted, such as in line, for someone else to arrive or finish a task, or while one is travelling somewhere. The automobile requires fast reflexes, making its operator busy and hence, perhaps for other reasons as well, making the ride more tedious despite being over sooner.
Different scholars use different definitions of boredom, which complicates research.[9] Boredom has been defined by Cynthia D. Fisher in terms of its main central psychological processes: "an unpleasant, transient affective state in which the individual feels a pervasive lack of interest and difficulty concentrating on the current activity."[10] Mark Leary et al. describe boredom as "an affective experience associated with cognitive attentional processes."[11] In positive psychology, boredom is described as a response to a moderate challenge for which the subject has more than enough skill.[12][full citation needed]
“I asked myself whether a life devoid of any affection, of any goal, a life one fills with a thousand trifles intended to relieve its monotony, populated with human beings one seeks out in order not to be alone and whom one flees to avoid being bored by them, whether such a life isn't ridiculous, whether anything whatsoever wouldn't be preferable.”
In conventional usage, boredom is an emotional and occasionally psychological state experienced when an individual is left without anything in particular to do, is not interested in their surroundings, or feels that a day or period is dull or tedious. It is also understood by scholars as a modern phenomenon which has a cultural dimension. "There is no universally accepted definition of boredom. But whatever it is, researchers argue, it is not simply another name for depression or apathy. It seems to be a specific mental state that people find unpleasant—a lack of stimulation that leaves them craving relief, with a host of behavioural, medical and social consequences."[1] According to BBC News, boredom "...can be a dangerous and disruptive state of mind that damages your health"; yet research "...suggest[s] that without boredom we couldn't achieve our creative feats."[2]
Absent-mindedness is where a person shows inattentive or forgetful behaviour.[20] Absent-mindedness is a mental condition in which the subject experiences low levels of attention and frequent distraction. Absent-mindedness is not a diagnosed condition but rather a symptom of boredom and sleepiness which people experience in their daily lives. When suffering from absent-mindedness, people tend to show signs of memory lapse and weak recollection of recently occurring events. This can usually be a result of a variety of other conditions often diagnosed by clinicians such as attention deficit hyperactivity disorder and depression. In addition to absent-mindedness leading to an array of consequences affecting daily life, it can have as more severe, long-term problems.
The most common way to define boredom in Western culture is having nothing to do. Boredom is generally viewed as an unpleasant emotional state in which the individual feels a pervasive lack of interest in and difficulty concentrating on the current activity. The condition corresponds more precisely to the French ennui, an existential perception of life’s futility. Ennui is a consequence of unfulfilled aspirations (Goodstein, 2005).