When the fasting person becomes angry or nervous, the excretion of adrenaline in his blood increases and may exceed the normal rate excreted in extreme anger and quarrel twenty- or thirty-fold.

If this happens early in the first part of the fasting day during the period of digestion and absorption, digesting and absorbing food in addition to all body systems will be in disorder. That is because the adrenaline loosens the gastric smooth muscles, decreases the shrinkage of the gallbladder, tightens the terminal blood vessels, widens the coronary vessels, increases arterial blood pressure and increases the amount of pumped blood to the heart as well as the heart rate.

If this anger or quarrels happen at the middle or end of the day after absorbing the remaining Glycogen in the liver is analyzed, the protein of the body becomes analyzed to amino bodies and many fat acids become oxidized. All this leads to the increase of glucose in the blood. So, it is burnt to provide the body with the necessary energy in quarrels. Hence, the energy is used irrationally. Some glucose may also be excreted in urination if it exceeds the normal percentage. Consequently, the body loses significant biotic energy uselessly and has to extract energy from fatty acids by oxidizing many of them. This may lead to generating the harmful ketone bodies into the blood.

The immense increase of adrenaline in the blood results in dispensing greater amounts of water from the body in Diuresis. The rate of Basal Metabolic is also increased due to the high adrenaline rate and cramping.

High levels of adrenaline may lead to heart attacks or sudden death due to high blood pressure and the increasing need for oxygen by the heart muscle due to its increasing heart rate. Anger also may lead to stroke among those people who suffer from high blood pressure and arteriosclerosis.

High levels of adrenaline due to psychological pressure in cases of anger and nervousness increase the formation of cholesterol from fat protein of low density which increases during fasting. It is proved that such cholesterol has a relation with arteriosclerosis.

For these known reasons and others to be known in the future, the Prophet, sallallaahu ‘alayhi wa sallam, advised the fasting person to be tranquil and avoid disputing, nervousness or quarreling. Abu Hurayrah, May Allaah Be Pleased with him, said that the Prophet, sallallaahu ‘alayhi wa sallam, said: “When anyone of you is observing fast, he should neither indulge in obscene language nor should he raise his voice; and if anyone reviles him or tries to quarrel with him, he should say, ‘I am fasting.’” [Al-Bukhaari and Muslim]

source: islamweb

https://islamstory.com/en/artical/1779/fasting-calmness-avoiding-quarrels