The mystery of why high blood pressure is difficult to lower: could snoring be the driving force behind it?

With the advancement of science and technology, modern medicine has become more and more specialized. Although doctors can become more professional in their own fields, their thinking is inevitably confined to one corner. However, diseases are often not classified according to textbooks, and patients often "get sick across borders."

This was a case I encountered recently in my outpatient clinic.

Mr. Li, 75 years old, came to my specialist clinic for rhinitis. During the consultation, I also asked about some conditions other than rhinitis, and he talked about a health problem. It turned out that Mr. Li had refractory hypertension. His blood pressure usually fluctuated around 160/100 mmHg, and sometimes even exceeded 200. Although he took antihypertensive drugs on time and had a relatively healthy diet, it was always difficult to control his blood pressure within an ideal range. Mr. Li sought help from the cardiovascular departments of major hospitals many times, but after various examinations, except for high blood pressure, no other obvious problems seemed to be found.

After doing some simple nasal and oropharyngeal examinations on Mr. Li, a clue gradually emerged. I asked Mrs. Li, who was also there, "Does Mr. Li snore when he sleeps at night?"

"Oh, please don't make too loud a noise. I've been used to it for decades!" said Mrs. Li.

"Is there such a situation, that the snoring is intermittent, and sometimes it pauses and there is no sound at all?" I continued to ask.

"Yes, yes, doctor, you are absolutely right." Mrs. Li replied eagerly, as if she had found a soulmate.

"I'll arrange a sleep monitoring for you. Maybe I already know the secret of why your high blood pressure is difficult to treat."

Mr. Li accepted my suggestion with some doubt. After a night of examination, the results showed that Mr. Li did suffer from obstructive sleep apnea-hypopnea syndrome (OSAHS), or snoring in short, and it was severe. The record showed that his longest apnea at night was more than one minute, and the lowest blood oxygen saturation was as low as 60%.

With this report in hand, I explained to Mr. Li in detail why his high blood pressure was related to his snoring.

First of all, we need to understand how the human body regulates blood pressure. Blood pressure regulation is a complex physiological process that involves the coordinated action of multiple systems such as the heart, kidneys, blood vessels, nerves, and endocrine system. Among them, the sympathetic and parasympathetic nerves are very important parts of the nervous system for regulating blood pressure. When the human body is in a state of tension, excitement, or stress, the sympathetic nerves will be excited, causing vasoconstriction, increased heart rate, and increased blood pressure; and when the human body is in a state of relaxation, rest, or sleep, the parasympathetic nerves will dominate, causing vasodilation, a slow heart rate, and a drop in blood pressure.

However, in snoring patients, due to the obstruction of the upper airway and apnea during sleep, the body repeatedly experiences hypoxia and repeated waking up due to suffocation. This state will stimulate the increased excitability of the sympathetic nerves, causing blood vessels to contract and heart rate to increase, which in turn leads to increased blood pressure. It is like someone is pinching the neck of a snoring patient while he is sleeping. When he feels like he is about to suffocate, the brain quickly asks the sympathetic nerves that were originally "on vacation" to come back to "work" and take over the body. We often say that although friends who snore seem to sleep soundly, they are actually fighting all night.

In addition, apnea causes chronic intermittent hypoxia in the body, and carbon dioxide will also be retained in the blood, causing a series of changes throughout the body. This repeated stress state at night will eventually lead to disorders in the secretion of some important hormones in the human body, such as catecholamines. When catecholamines are secreted excessively, the heart rate increases, blood vessels contract, and blood pressure rises. Moreover, long-term hypoxia will affect the function of vascular endothelial cells, accelerate the process of atherosclerosis, and further aggravate the condition of hypertension. In the long run, metabolic syndromes such as hypertension, diabetes, and heart disease will quietly sow the seeds of disaster.

After listening to my explanation, Mr. Li suddenly realized: "It turns out that the reason why my high blood pressure couldn't be lowered was because of the 'invisible killer', snoring!"

Finally, after treatment, Mr. Li's snoring symptoms gradually improved. At the same time, after a multidisciplinary consultation with the internal medicine department, his blood pressure was also significantly controlled.

In medicine, each discipline is a star, and the stars connect to form a brilliant galaxy, illuminating the path to health. Diseases often cross boundaries, and we doctors also need to broaden our horizons and explore the causes of diseases with a holistic perspective in order to relieve patients' suffering.