Secondary hypertension diagnosis and treatment and exercise prescription for obese patients: Clinical guidelines for etiological identification and scientific intervention

Secondary hypertension differs from primary hypertension. It refers to elevated blood pressure that occurs as a complication of certain diseases, where elevated blood pressure is merely a clinical manifestation of the underlying condition. The causes of secondary hypertension are complex, and it accounts for less than 10% of all hypertension cases. This figure is only a rough estimate due to factors such as the subjects surveyed, sample size, and diagnostic criteria. In recent years, with ongoing research, the causes of some cases of secondary hypertension have been clarified, potentially leading to a fundamental cure.

The main causes of secondary hypertension include: endocrine disorders, such as primary aldosteronism, pheochromocytoma, thyroid dysfunction, and hyperparathyroidism; kidney diseases, such as renovascular hypertension and renal parenchymal hypertension; aortic coarctation, i.e. localized or widespread stenosis caused by congenital malformation of the aorta; genetic and familial diseases; and drug-induced hypertension, such as elevated blood pressure caused by oral contraceptives, growth hormone, androgens, and sympathomimetic drugs.

Secondary hypertension often presents with certain unique or unusual characteristics, manifesting as abnormal clinical features such as younger age of onset, excessively high blood pressure, difficulty in treatment, vascular murmurs, and cardiac arrhythmias. It may also be detected during physical examinations by finding findings such as hypokalemia, proteinuria, and retinopathy. These are preliminary clues for diagnosing secondary hypertension. Because secondary hypertension is diverse, with complex and varied clinical manifestations involving multiple disciplines, screening and diagnosis can be challenging. If clues of secondary hypertension are found, or if a patient has uncontrollable hypertension, relevant examinations should be conducted based on the individual's specific symptoms.

Blood cholesterol, triglycerides, fundus examination, kidney function, and measurements of renin, aldosterone, and catecholamine activity are of significant indicative value. Pheochromocytoma of the adrenal medulla can cause episodic hypertension, a typical type of secondary hypertension. Pheochromocytoma can increase the synthesis of adrenaline and noradrenaline. When these pressor substances are secreted into the bloodstream in large quantities, the heart's pumping capacity suddenly increases, and at the same time, small arteries constrict significantly, causing a sudden increase in peripheral resistance, resulting in a sudden rise in blood pressure that can last for hours or even days.

Because pheochromocytomas of the adrenal medulla intermittently release pressor substances, blood pressure can remain within the normal range during the intervals between these releases. After surgical removal of the pheochromocytoma, arterial blood pressure tends to normalize. The treatment for secondary hypertension differs completely from that for primary hypertension. Secondary hypertension has a clear primary cause, and treatment should focus on identifying and addressing the root cause. Drug or surgical treatment of the primary disease can stabilize and improve the patient's hypertension. Early detection, diagnosis, and treatment of secondary hypertension are also crucial to improve detection and cure rates.

Among the comprehensive treatment interventions for obesity combined with hypertension, physical exercise is an important and effective measure. Appropriate physical exercise can lower blood pressure in hypertensive patients and simultaneously burn excess body fat, reducing the degree of obesity. Before starting any weight-loss exercise program, obese patients with hypertension should undergo a physical examination, medical examination, and exercise stress test to determine the appropriate exercise intensity, ensuring the safety and effectiveness of the physical exercise.

Medical examinations include a series of tests related to obesity and hypertension, mainly fasting blood tests (lipidemia, insulin, and blood glucose), resting blood pressure, heart rate, and electrocardiogram. Exercise stress testing can be performed using a step test, stationary bike, or treadmill, recording blood pressure and electrocardiogram before exercise and immediately after each level of exercise load. Based on the test results, an exercise prescription suitable for obese patients with hypertension is developed.

Generally, exercise intervention is considered effective based on the patient's tolerance for exercise. As long as the patient can tolerate the exercise, it can have a positive effect on lowering blood pressure. Exercise therapy programs for hypertension emphasize exercise intensity; moderate to low-intensity exercise is more effective at lowering blood pressure than high-intensity exercise. Moderate to low-intensity aerobic exercise is precisely the most effective way to burn body fat. In addition to traditional aerobic training, strength training also has some effect on lowering blood pressure and cholesterol; however, for safety reasons, strength training must be conducted under the supervision of a professional.

Therefore, it is recommended that obese patients with hypertension choose regular moderate-to-low intensity aerobic exercise. The intensity should be chosen based on the results of the aforementioned medical examinations and exercise stress tests. Heart rate is generally used as a monitoring indicator for exercise intensity, with the upper limit of the target heart rate set at 40% of the heart rate reserve. However, this should be adjusted based on individual blood pressure and exercise tolerance. It is recommended to retest the exercise stress test every 1-2 months to adjust the exercise intensity. Studies have confirmed that each exercise session must last for more than 40 minutes to achieve good fat loss results. It is recommended that obese patients with hypertension maintain 1-2 hours of aerobic exercise daily, maintain good exercise habits, and pay attention to gradual progression and consistency.

Numerous studies have demonstrated that physical exercise interventions have positive therapeutic effects on obesity and hypertension. Exercise intervention is a crucial component of comprehensive treatment interventions for both conditions. While physical exercise does not have a specific effect on health promotion, the intensity, duration, and type of exercise should vary depending on the specific disease and health condition.

For patients with hypertension, the following precautions should be taken when participating in physical exercise: Exercise is best done in the afternoon to avoid peak secretion of adrenaline and noradrenaline. 5:00 AM to 11:00 AM in winter is a high-risk time for stroke and myocardial infarction. Hypertensive patients should not exercise in the early morning when the weather is cold. Pay attention to keeping warm and appropriately extend the warm-up time. Avoid competitive or high-intensity exercises that cause significant fluctuations in blood pressure. Consciously relax all muscles during exercise and try to avoid holding your breath. When blood pressure is not under control or when you are not yet accustomed to exercise, avoid bending over or lowering your head; keep your head at heart level.

If any discomfort occurs during exercise, it should be stopped immediately to avoid causing or worsening adverse reactions. Exercise should follow the principle of gradual progression. The intensity of exercise should vary from person to person, starting with low intensity and gradually increasing the amount of exercise until the prescribed intensity is reached. Persistence is key. The blood pressure-lowering effect of exercise training is reversible; if exercise is stopped, the training effect may completely disappear. Therefore, long-term exercise is necessary to achieve satisfactory blood pressure-lowering results.