* Fatigue (also called exhaustion, tiredness, lethargy, languidness,
languor, lassitude, and listlessness) is a subjective feeling of
tiredness which is distinct from weakness, and has a gradual onset.
Unlike weakness, fatigue can be alleviated by periods of rest. Fatigue
can have physical or mental causes. Physical fatigue is the transient
inability of a muscle to maintain optimal physical performance, and
is made more severe by intense physical exercise.
* Mental fatigue is a transient decrease in maximal cognitive
performance resulting from prolonged periods of cognitive activity. It
can manifest as somnolence, lethargy, or directed attention fatigue.
* Medically, fatigue is a non-specific symptom, which means that it has
many possible causes. Fatigue is considered a symptom, rather than
a sign because it is a subjective feeling reported by the patient,
rather than an objective one that can be observed by others. Fatigue
and ‘feelings of fatigue’ are often confused.
* Physical fatigue, or muscle fatigue, is the temporary physical
inability of a muscle to perform optimally. The onset of muscle
fatigue during physical activity is gradual, and depends upon an
individual's level of physical fitness, and also upon other factors, such
as sleep deprivation and overall health. It can be reversed by rest.
* Physical fatigue can be caused by a lack of energy in the muscle, by a
decrease of the efficiency of the neuromuscular junction or by a
reduction of the drive originating from the central nervous system.
* The central component of fatigue is triggered by an increase of the
level of serotonin in the central nervous system. During motor
activity, serotonin released in synapses that contact motoneurons
promotes muscle contraction. During high level of motor activity, the
amount of serotonin released increases and a spillover occurs.
Serotonin binds to extrasynaptic receptors located on the axon initial
segment of motoneurons with the result that nerve impulse initiation
and thereby muscle contraction are inhibited.
* Mental fatigue is a temporary inability to maintain optimal cognitive performance. The onset of mental
fatigue during any cognitive activity is gradual, and depends upon an individual's cognitive ability, and
also upon other factors, such as sleep deprivation and overall health. Mental fatigue has also been
shown to decrease physical performance.
* It can manifest as somnolence, lethargy, or directed attention fatigue. Decreased attention is known as
ego depletion and occurs when the limited 'self-regulatory capacity' is depleted.
* It may also be described as a more or less decreased level of consciousness.
* In any case, this can be dangerous when performing tasks that require constant concentration, such as
operating large vehicles. For instance, a person who is sufficiently somnolent may experience
microsleep. However, objective cognitive testing can be used to differentiate the neurocognitive
deficits of brain disease from those attributable to tiredness.
* The perception of mental fatigue is believed to be modulated by the brain's reticular activating system
* Fatigue is a normal result of working, mental stress, overstimulation and understimulation, jet lag or
active recreation, depression, and also boredom, disease and lack of sleep. It may also have chemical
causes, such as poisoning or mineral or vitamin deficiencies. Chronic blood loss frequently results in
fatigue, as do other conditions that cause anemia. Fatigue is different from drowsiness, where a patient
feels that sleep is required. Fatigue is a normal response to physical exertion or stress, but can also be
a sign of a physical disorder.
* Temporary fatigue is likely to be a minor illness like the common cold as one part of the sickness
behavior response that happens when the immune system fights an infection.
* Emotional exhaustion is a chronic state of physical and emotional
depletion that results from excessive job and/or personal demands
and continuous stress. It describes a feeling of being emotionally
overextended and exhausted by one's work.
* It is manifested by both physical fatigue and a sense of feeling
psychologically and emotionally "drained“
* Most emotional exhaustion research has been guided by Maslach's and
Jackson's three-component conceptualization of burnout. This model
suggests burnout consists of three interrelated parts: emotional
exhaustion, depersonalization, and diminished personal
accomplishment. Depersonalization, also called "dehumanization",
refers to a set of callous and insensitive behaviors displayed by a
worker toward a client. Diminished personal accomplishment refers
to negative evaluations of the self.
•Negative and forceful
•Negative and not in control
•Negative and passive
•Positive and lively
The emotion annotation and representation language (EARL) proposed by the Human-Machine Interaction Network on Emotion (HUMAINE) classifies 48 emotions.
*Assume 150 lbs (Pounds) body weight
*Assume a ~2400 “Food Calorie” diet => 2400
*1300 “Food Calories” required/day for Body at
Rest Metabolism i.e. Survival
*2400Kcal/day = 100Kcal/hr = 116 Watts Body
*Running for 60 mins, 5 Miles/hr [=12 minute
Mile] needs 544 Food Calories/Hour
* Brain is ~2% of body weight and consumes ~20% of body energy.
* It is most sensitive to energy needs, if deprived of energy for just ~10mins it sustains
* If body consumes ~116 Watts/Hr the brain consumes ~23 Watts/hour or 480 “Food
* Which is 20% of Body Energy needs
* The Reality: Humans who exclusively do mental work can use up 35% of body energy
w/ their brain => 840 “Food Calories” / day
* The Myth is that some research says Thinking increases energy consumption by +20-50
“Food Calories”/day BECAUSE we don’t (!@#!@$@#$%#$%^%%^) think that much
(Really???) and only occasionally. But the reality is a lot… a whole lot of people
Exclusively Think for a Living in today’s economy. This research is a Defunct Legacy
that needs to be archived.
* Which [The Reality] as per our calculations is equivalent to Running 5Miles/Hour for
* No Wonder Mental Work is extremely exhausting!!!
* Definition: Emotions are Overwhelming Theme of Thoughts in a Human Brain
* Myth: Someone who cries a lot IS EMOTIONAL… could be!!! But by our definition any overwhelming
theme of thoughts is Emotions. So even Laughing a lot could be a sign of hyper-emotionalness
* In Reality: Having a large portfolio of Theme’s of Thoughts in our Brains makes us Emotional (In a
* A brain stores millions of thoughts… all that is necessary to display Emotional Behaviour is for something
to Trigger a Theme(s) of thoughts, and they triggering each other… causing an Avalanche!!!
* Even Animals have Sight and Listening but what makes Humans emotional is Speech + Vocabulary which
is extremely effective at hyper linking thoughts into Themes aka Emotions which get triggered together
* Some people like to believe (i) Brain has unlimited capacity (ii) we use only 5% of our brain and the rest
is free for use….. I don’t want to discuss that and right now I will straightaway put my point which is ….
Any huge Avalanche of Thoughts / Themes of Thoughts / Emotions can overwhelm the brain and prevent
it from acting Optimally (???) and Rationally (???)
* Hence Emotions and Emotional Behaviour is in Absolute Certainty “Suboptimal” from a non-emotional
plane of reference !!!
* Our Mental Capability increases with age!!!
* And so does our Emotional Baggage!!! Which can overwhelm our Mental Capability [Rationality] many
* Top Strategy Consulting companies demand Their Consultants Show “Empathy” which might be a
Business Need BUT IS AN OXYMORON!!! See definition of Empathy above.
* Where I live, Hospital Staff are extremely rude to patients… I for one understand that Doctors and
Surgeons use their Brains a lot and I also understand that Empathy would suppress their
Rational/Diagnosis/Judgement into sub-optimality… (Yes! Surgeons also need Stable/Firm hands for
surgery but its primarily their brains succeeding w/ surgery not just their hands)
* So I don’t expect Surgeons, Doctors and Emergency Services Personnel to be very Empathetic and rather
just be to the point… Yeah I know it sucks when you are at the receiving end…. But if you realise that if
they stay rational they might actually be better off in saving your life than if they got emotional at your
pain and suffering and started weeping and crying in front of you and your family.
* What peeves me off is when Nurses and Ward Attendants pick that up from Surgeons and behave
extremely rudely and arrogantly, they think it’s the right thing to do. In fact according to me Nurses
and Ward Attendants, are the ones who need to be Empathetic.
* Anyway, sorry for digressing… now coming back
* Ref: DC and AC electric currents
* One steady avalanche of Emotions/Thought-Themes can by themselves Hyper-Metabolise the brain to
the levels mentioned on the Mental Exhaustion slide. (Just like D.C. Electricity Current)
* If that was not bad enough Alternating Emotions throughout the day e.g. Fear -> Sadness -> Relief can
be even more exhausting to the brain.
* Agreed; kids eat less in proportion to their physique. But their diet is
thoroughly sufficient for them to be physically active all throughout the
* The problem is most adults appear to be constantly exhausted…
* Emotional Exhaustion seems to be ∝ Σ (Intensity x |Δ emotions|)
* Mental Exhaustion & Emotional Exhaustion -> Burnout
* Kids laugh when happy, cry when hurt, display very little Mental
Exhaustion, or Emotional Baggage/Exhaustion…
* Rule: In Knowledge work folks are almost never physically exhausted
* Because we don’t do much physically strenuous work. Our exhaustion is
completely Mental and Emotional.
* The “Promise” of Fun Work itself might be flawed but the concept of Fun
@ Work reduces Mental & Emotional Exhaustion and Burnout…
* And since in Knowledge work the Employee controls the Source of
Production in his head this could only lead to more and better outcomes…