Obesity and Cardiovascular Disease: A Direct Link Between Hypertension, Stroke, and Brain Injury

Obese individuals are more prone to hypertension.

Obese individuals are prone to hypertension. The pathogenesis is as follows: Obese individuals have a significant increase in body fat, leading to a corresponding increase in blood volume. This increases external resistance in the arterioles, forcing the heart to work harder and increase cardiac output to ensure blood supply to peripheral tissues. This resulting arteriole sclerosis promotes hypertension. Furthermore, the water and sodium retention present in obese patients further increases circulating blood volume, exacerbating hypertension.

If blood pressure remains high for a long period of time, it can damage the cardiovascular, cerebrovascular, and renal blood vessels, eventually leading to serious and life-threatening complications such as myocardial infarction, stroke, and kidney failure.

Although obesity can cause high blood pressure, clinical observations show that many obese individuals have normal blood pressure, which may be related to the body's compensatory abilities. Of course, these compensatory abilities are limited, and once they are lost, blood pressure will rise. Weight loss is an effective measure to prevent high blood pressure; even for obese individuals who already have high blood pressure, weight loss through a low-calorie diet can alleviate the condition.

Genetic factors also play a role in the development of hypertension in obese individuals. Recent studies have found that hypertension is often accompanied by hyperinsulinemia, including some hypertensive patients with normal weight. The direct or indirect effects of hyperinsulinemia on blood vessel walls have a significant impact on the development of hypertension. These patients often have a familial predisposition to the disease.

Medical research indicates that the prevalence of hypertension in overweight adults is approximately four times that of adults of normal weight.

Obesity can easily lead to pulmonary vascular obstruction.

Medical research has shown a close relationship between obesity and fatal sudden pulmonary artery occlusion. This type of blood clot, which blocks the pulmonary artery, often travels with the bloodstream from the thigh to the lungs.

Researchers, through an analysis of 20 years of hospital medical records, found that obese patients are 25 times more likely to die from sudden pulmonary embolism than the general population. This risk is even higher in people under 40. Sudden pulmonary embolism is the third leading cause of cardiovascular death after myocardial infarction and stroke.

Obesity can trigger cardiovascular disease.

Cardiovascular disease has gradually become the leading cause of death among humans, affecting people of all ages, genders, and regions. Globally, 17 million people die from cardiovascular disease each year, with 80% of these deaths occurring in low- and middle-income countries.

The incidence of obesity in my country is increasing, and heart health problems are becoming increasingly serious. In 2006, the "National Nutrition and Health Status Report of Chinese Residents," jointly released by the Ministry of Health, the Ministry of Science and Technology, and the National Bureau of Statistics, showed that obesity is a serious problem in my country. One in five adults is overweight, and one in ten is obese. The current number of overweight and obese individuals is over 200 million and over 60 million respectively, with a childhood obesity rate of 8.1%. Moreover, the number of obese individuals is increasing year by year. Compared with the 1992 National Nutrition Survey, the overweight rate among adults has increased by one-third, and the obesity rate has doubled.

Another survey of 27 countries, including China, revealed that 6 out of 10 doctors recognized abdominal obesity as a significant risk factor for heart disease; only a small percentage recognized that excessive waist circumference increased their risk of heart disease, with only 1 out of 5 saying their doctor had measured their waist circumference. This survey, supported by the World Heart Federation, showed that while there is awareness of the link between abdominal obesity and heart disease in China, neither doctors (38%) nor patients (23%) took action to address it. Only a small percentage of patients recognized that increased waist circumference also increases the risk of cardiovascular disease; on average, only 19% of patients with risk factors had their waist circumference measured.

Obesity can damage the brain.

Swedish medical researchers have shown that obesity can have adverse effects on the brain. Obese women in adulthood are more likely to experience brain tissue loss, a condition known as brain atrophy, which can lead to impaired brain function and dementia.

This study followed 290 women for 24 years, with four follow-up examinations. At the final examination, the women, aged 70-84, all underwent computed tomography (CT) scans to measure brain atrophy. Researchers compared the CT results with the women's BMI values ​​and found that being overweight or obese increased the risk of brain damage, specifically in the temporal lobe, which is responsible for language, memory, and hearing.

This study showed that women with brain atrophy had an average BMI 1.1–1.5 kg/m² higher than women with normal BMI. Overall, women's BMI increased during the 24-year study period, but the increase was greater in those with signs of brain tissue damage. Furthermore, researchers found that if these women's BMI increased, their risk of brain atrophy also increased by 13%–16%; women with high BMI are at risk of dementia, and other studies have yielded similar findings.

Researchers believe that more research is needed to explain the relationship between obesity, brain atrophy, and dementia, but the findings provide another important reason to maintain a healthy weight.

**Stroke is closely related to obesity.**

Stroke, also known as cerebrovascular accident, is a general term for acute cerebrovascular diseases, including cerebral hemorrhage, subarachnoid hemorrhage, cerebral infarction, and cerebral embolism. Cerebral hemorrhage refers to bleeding from a ruptured blood vessel in the brain; cerebral infarction is caused by arteriosclerosis, narrowing of the lumen, and thrombus attachment within the blood vessel, resulting in stagnation of blood circulation; cerebral embolism is caused by a thrombus formed in the coronary artery, carotid artery, or vertebral artery breaking off and traveling into the brain via the bloodstream, blocking small blood vessels in the brain.

The brain is the "command center" of the body's control system, much like the central processing unit (CPU) of a computer. Various central nervous systems converge here, such as the sensory center, motor center, auditory center, olfactory center, visual center, and visceral activity center. Important commands are issued from here. The brain has a very high blood demand because vigorous metabolism is necessary to meet the brain's needs for performing complex physiological functions. More than 20% of the oxygen required by the human body is consumed by the brain, making brain cells highly sensitive to ischemia and hypoxia. Therefore, when cerebral blood circulation is impaired, brain tissue can die due to ischemia and hypoxia, directly threatening health and life.

Currently, stroke has become the third leading cause of death after cancer and heart disease. In 2002, 1.65 million people died from stroke in my country, ranking first in the world. Stroke not only has a high mortality rate but also a very high disability rate. Approximately one-third of stroke patients in my country die, and one-third suffer permanent disability.

Studies have found a close link between stroke and obesity, because obesity easily leads to complications such as hypertension, arteriosclerosis, diabetes, and dyslipidemia. These complications greatly increase the risk of stroke. Sustained high blood sugar damages the inner walls of blood vessels, dyslipidemia increases blood viscosity, and hardened arteries lose elasticity and are prone to rupture. Coupled with the induction of hypertension, it becomes inevitable that cerebral blood vessels will be blocked or rupture and bleed.

**Excessive obesity affects intelligence**

Swedish scientists have discovered that obesity can affect intelligence. The temporal cortex of the brain is responsible for learning and thinking, and obesity can impair the function of this area, affecting memory and language abilities.

Research has shown that one of the most important functions of the temporal cortex is to understand and process received language and find the most appropriate way to express it. Language is one of the most important aspects that distinguishes humans from animals. It is language that provides humans with the best vehicle for complex thinking, while the inability to correctly understand language will hinder thinking. In addition, the temporal cortex is also related to medium- and long-term memory. Once the function of the temporal cortex is impaired, it will seriously affect a person's memory and make learning activities very difficult, which is a prerequisite for intellectual development.

Researchers believe that obesity affects intelligence by influencing the physiological function of the temporal cortex. One major reason is that obesity reduces cerebral blood flow. Reduced cerebral blood flow directly damages brain function, causing sparse areas in the cerebral cortex, which interferes with mental activity and behavior. In the case of sparse areas in the temporal cortex, this can lead to memory loss, impaired language comprehension, and unclear thinking. Another reason is that under normal circumstances, the production and consumption of lipids in the human body are in a dynamic balance, and blood lipid levels remain at a relatively stable level. If one or more of these indicators fail to maintain normal levels, abnormal blood lipid levels occur.

Obese individuals often have unhealthy lifestyle habits such as overeating, a preference for high-fat foods, and lack of exercise. Due to excess body fat and insufficient fat processing capacity, the body's tissues mobilize and utilize free fatty acids less, leading to abnormally high blood fat levels. Extensive epidemiological data shows that the degree of obesity is directly proportional to elevated levels of triglycerides, total cholesterol, and low-density lipoprotein cholesterol in the blood, and inversely proportional to elevated levels of high-density lipoprotein cholesterol.

The role of low-density lipoprotein cholesterol (LDL-C) is to transport cholesterol from the liver to other tissues. During this transport, it often leaves deposits that adhere to the walls of blood vessels, causing arteriosclerosis. Therefore, it is also known as "bad" cholesterol because high levels can increase the risk of cardiovascular disease.

High-density lipoprotein cholesterol (HDL-C) has the opposite function of low-density lipoprotein cholesterol (LDL-C). It can transport cholesterol from various parts of the body back to the liver for processing, reducing the risk of cardiovascular disease. Therefore, it is also known as "good" cholesterol.

Obese individuals often have higher levels of triglycerides, total cholesterol, and low-density lipoprotein cholesterol than normal, while their high-density lipoprotein cholesterol is lower than normal, thus posing a higher risk of cardiovascular disease.

Numerous studies have found that if obese individuals adjust their diet to reduce energy intake and increase appropriate exercise to burn more energy, their abnormal blood lipid levels will improve significantly as they gradually lose weight.