Constipation is twice as likely to occur in women than in men, so why is this the case? Clinical practice has observed that more women than men suffer from constipation, and foreign survey data from Europe and the United States show that women are twice as likely to suffer from constipation as male patients. So why does this happen? This is mainly related to the instinctive bladder-anal reflex of the human body. The nerves of the urethral and anal sphincters are derived from the same sympathetic, parasympathetic and somatic nerves, meaning that the bladder and anus are innervated by common vegetative and somatic nerves. When urinating, the electrical activity of the external sphincter is fully inhibited, while the electrical activity of the internal sphincter increases. At this time, the internal sphincter is in a state of contraction in order to prevent the overflow of stool, which is not under conscious control and is a normal physiological reflex. In order to prevent the discharge of feces in the rectum, through the bladder-rectum reflex, the tension of the internal sphincter is higher than that of men, plus women have a short urethra and more opportunities to suffer from urinary tract infections, which often lead to frequent urination and more easily stimulate the spasm of the internal sphincter. At this time, under the influence of the reflex of the internal rectal sphincter, the internal sphincter spasms, the rectum expands, the stool storage increases, water is excessively absorbed, and thus constipation occurs. Why is constipation easily caused by anal pain? Many patients who have suffered from anal diseases or have undergone anal surgery may have a common experience, that is, no matter what the reason is, once the pain in the anus comes on, the stool will be dry and difficult to solve. The author analyzes the causes of constipation mainly from two aspects: 1, psychological factors: due to the patient’s fear of defecation to aggravate anal pain and thus tolerate stool for a long time, resulting in the rectum of the feces stay too long, too much, excessive absorption of fecal water by the rectum, resulting in fecal hard knots. 2, reflex factors: due to various anal inflammatory stimulation, traumatic stimulation (such as postoperative) will cause strong contraction of the anal random muscles (random muscles are governed by human consciousness), random muscles mainly include the external anal sphincter and the puborectalis muscle above it, these two muscles are stimulated to compress the internal sphincter at the same time, finally causing the muscle tone of the internal sphincter to increase. The internal sphincter is located on the inner side of the external sphincter, and the two muscles are like two movable cannulae that can move up and down within a certain range. The internal sphincter is a continuation of the circular muscle layer of the GI tract and is not under conscious control and has the inherent characteristics of the circular muscle of the GI tract, i.e., it is easily spasticized. When pain is caused by various anal factors, the external sphincter is stimulated to contract first, followed by the contraction of the internal sphincter. If the anal pain-causing factors can disappear quickly, the contraction of the internal and external sphincters will slowly relax; if the anal pain-causing factors (such as inflammation not relieved) still exist, due to the characteristics of the internal sphincter, it will eventually produce spasm and even thickening. At this time, the spasm of the internal sphincter causes the rectum to dilate reflexively, and the accumulation of stool increases and water is excessively absorbed, which is the cause of constipation due to the loss of relaxation of the internal sphincter. Why is it important to develop a good habit of regular bowel movement? In life, there are often people who, because they are really busy at work or because conditions do not allow, even if they have the urge to defecate, they will artificially tighten the anus until the urge to defecate disappears, which professionally belongs to the “retrograde peristaltic” reflex. If the cerebral cortex frequently inhibits defecation, on the one hand, the sensitivity of the rectum to feces is reduced; on the other hand, feces stays too long in the rectum and sigmoid colon, water is excessively absorbed and feces becomes dry, resulting in stubborn constipation. The highest “command” of the human body to control defecation, the cerebral cortex, has a regulatory role in the sacral spinal defecation center. When artificially trying to suppress defecation, the external anal sphincter will contract strongly, and the contracted external sphincter will compress the internal sphincter, causing the internal sphincter to contract. At this time, due to the inherent characteristics of smooth muscle (the gastrointestinal system is smooth muscle), the contracture of the internal sphincter is reflexive expansion of the rectum, rectal space is increased, more feces is retained in the rectum, due to the expansion of the rectum, the tension of the rectal wall is reduced, and will cause the stimulation of the defecation reflex to weaken or disappear, the longer the feces stays, the more water is absorbed by the intestinal wall, so the more likely to cause constipation, and even more patients The longer the stool stays, the more water is absorbed by the intestinal wall, so the more likely it is to cause constipation. Therefore, it is very beneficial to avoid constipation by defecating immediately. In addition, because defecation is a complex, coordinated, temporal conditioned reflex involving the cerebral cortex, it is important to develop a good habit of regular defecation and not to easily disrupt your own routine, which is not only important for defecation, but also vital for maintaining the stability of your “biological clock”.