Stress (from the Latin stringere ‘tighten’ through its derivative in English stress ‘material fatigue’) is a physiological reaction of the organism in which various defense mechanisms come into play to face a situation that is perceived as threatening or of increased demand. It is the physiological or biological response of an organism to an environmental condition or a stimulus. Stress is a body’s way of reacting to a challenge.According to the stressful event, the body’s way of responding to stress is through the sympathetic nervous system of activation that gives rise to the fight or flight response. Because the body can not maintain this state for long periods of time, the parasympathetic system tends to return the body to more normal physiological conditions (homeostasis). In humans, the word stress usually has a negative connotation (the opposite might be the Nibbāna or the Nirvana principle of Sigmund Freud. Negative stress is one that in an animal (including humans) exceeds the potential for homeostasis or balance of the body causing fatigue, increased levels of anxiety, irritability and anger. Sustained stress can cause the appearance of physical consequences, due to the increase in energy expenditure, a greater speed of action, less rest than necessary and the consequent exhaustion of forces. The Nirvana Principle is a concept that alludes in psychoanalysis to the efforts of the psyche tending to eliminate, suppress or reduce to a minimum possible the tension of the excitement, be it motivated from external stimuli or respond to internal motions. The concept was originally proposed by the English psychoanalyst Barbara Low and collected, almost unchanged, by Sigmund Freud in the context of the new definitions of his second topic Stress has two factors, the stimulus and the reaction to these stimuli. For example, a person subjected to a high environmental load, if he has an average reaction, will become saturated and produce tension, stress and suffering. Similarly, a person with little environmental burden if their reactions are exaggerated, will remain permanently stressed. On the contrary, a normal person with a low environmental load will not suffer stress and a person with a very high environmental load who does not develop any reaction will never have stress. There are 4 possibilities. Therein lies the problem of suffering. Nothing less. Because suffering really is a reaction of adaptation to an external stimulus mediated by the reaction whose intensity will depend on how demanding and costly that adaptation is. And adaptation is made from the expected scenario and the current one, that is, from attachment and / or aversion. For example, the father or mother dies, which can create stress for those who maintain perspectives regarding the continuity of the dead person. Or you lose all your fortune on which all your plans depended. Adaptation consists of synaptic ruptures which, as we know, produces physical pain and is what we call suffering. The necessary condition for there to be suffering is the emotional reaction. It is not new, as the Buddha said on many occasions, vedanā . A bad word translated as «sensation», and it is emotional reaction: attachment, aversion or nothing. The same as the amoeba, if it is hot, it flees looking for the cold until it is comfortable, feels attachment and stops. There it remains, neutral or null reaction, until it cools, feels aversion and again moves until it is comfortable again. And so. It works with every living thing. It works up to you If the amoeba does not have an emotional reaction, it can be cooked alive and it will not have any stress. On the contrary, if she is very sensitive she will be permanently stressed. The emotional reaction depends on wisdom, which is its effect on behavior. The environment depends on conditionality, that is, on kamma. So we can combine: Hell has no wisdom so the infernal being is extremely sensitive, and to make it even worse, the entropy is very high, that is, the change, the external stimuli. So we have it wrong on both sides and the result is extreme stress. On the other hand, the celestial worlds, of the devas, have a very low entropy. Almost never happens anything and also his ignorance is low so that in this environment the stress is minimal. High low … but not null. Null stress is exclusively achieved through the attainment of arahantado, where there is no longer ignorance and in this way the emotional reaction is not given. It reacts, but without emotion. Emotion, whose etymological meaning is emotional, before the movement, disappears. We do not move by emotions but by convenience.Emotions are psychophysiological reactions that represent modes of adaptation to certain stimuli of the individual when he perceives an important object, person, place, event or memory.Psychologically, emotions alter attention, raise certain behavior guiding the individual’s responses and activate associative networks relevant to memory. The extreme case of suffering on the human plane would be a person in constant anxiety crisis and with regular panic attacks. He is dying in front of any trifle, even a fleeting thought. It is the end of suffering: you die several times a day, but you have not died. The arahant does not flinch, although the environment becomes really complicated. In between we can have the bhikkhus, who isolate themselves so that the environment does not harm them, although if they do not develop jhānas, they tend to go mad because of obsessive thoughts. And in between, to the laity leading a normal life. Is it worth it to shave, to wear yellow, not to urinate standing or on water? If you light up, it is the same to be protected than in the middle of the mess. In addition, in the latter case you can check the fabulous effects of lighting. If you do not light up, wherever you are, you have a head that can be worse than a whip with seven heads. That is. Bhikkhu? Only for someone to feed you. Really?