Why do I sweat less when I am startled?

I believe everyone has this feeling, that is, we sweat when the weather is hot, but not when it is cold. In fact, no matter what the weather is, the human body will sweat normally, but when the weather is cold, the sweat secreted by the sweat glands is easily evaporated. So, why do some people not sweat?

Why don't you sweat?

People often have the same feeling. When they encounter strong external stimulation, they will find themselves "sweating all over". In fact, this is a normal reaction. It is because mental stimulation increases nerve impulses and increases the secretion of acetylcholine, which leads to excessive sweating. But some people "have no sweat when they are frightened". Why is this? Little or no sweating on the surface of the skin can be caused by abnormalities in the sweat glands themselves or abnormalities at a certain level of the neural pathway.

When a person sweats, you can see obvious beads of sweat, so everyone thinks he sweats a lot; some people are like winter swimmers, you can't see them sweat, but you can clearly see the heat coming out of their bodies; in addition, some people have more body fluids, so they sweat more; some people have less body fluids, so they sweat less. The amount of sweating during exercise is also related to drinking water. If you drink a lot of water before exercise, the amount of sweating will increase due to the increase in body fluids. For exercise, when doing the same amount of exercise, the person who sweats less should have a better physique, because his body has a stronger ability to self-regulate. "If you don't sweat under normal circumstances, it's completely normal, which means you have a good physique. On the contrary, some people sweat easily after a little exercise, which means they have a disease. If you feel hot but don't sweat, it's a problem with your sweat glands (congenital or acquired). In this case, it's best to go to the hospital for a check-up to find out why you don't sweat.

The main causes of not sweating are as follows

(1) Congenital hypoplasia of sweat glands or lack of sweat glands can manifest as systemic or localized anhidrosis.

(2) Certain skin diseases, such as severe ichthyosis, scleroderma, leprosy, radiation dermatitis, and skin atrophy, can cause localized anhidrosis.

(3) Neurological damage, such as transverse myelitis, poliomyelitis, paralysis, and local damage to the sympathetic nerves, medulla oblongata, and pons can all cause generalized or localized anhidrosis.

(4) Certain visceral diseases, such as diabetes, diabetes insipidus, chronic nephritis, myxedema, malignant tumors, etc., in addition, vitamin A deficiency, etc., can also cause systemic anhidrosis.