Can a small towel, held every day, lower your blood pressure?

Popular saying: The "clench-and-relax" towel movement can produce a large amount of nitric oxide, which causes blood vessels to dilate and lower blood pressure.

Real points:

The claim that holding a towel can lower blood pressure is not groundless. It comes from a foreign hand-grip training study. However, if it can be lowered, it is also due to exercise. Exercise and improving lifestyle are all non-drug measures for treating high blood pressure. If non-drug measures cannot control blood pressure to the target, please take medication in time.

Verifier: Li Qing | Director of Nephrology Department, Tianjin University Teda Hospital

Recently, a netizen asked a question on Tencent: Can holding a towel lower blood pressure? Along with the question, there was also an article introducing "holding a towel to lower blood pressure". The article mentioned that the "holding-relaxing" towel action can produce a large amount of nitric oxide, which can dilate blood vessels and have the effect of lowering blood pressure. Is a towel really so magical?

1. The claim that towels can lower blood pressure comes from a foreign hand grip training study

The "holding a towel to lower blood pressure" mentioned in the circulating article comes from Japan's NHK health program "What Teachers Didn't Teach You", and professional guidance was provided by Professor Toshio Hisashiro of the Comprehensive Health Checkup Center of Nihon University School of Medicine.

(NHK program reminds everyone the key points of holding a towel: when holding the towel, the thumb and other fingers cannot be clasped together, hold the towel for 2 minutes; 2 times for each hand, 4 times in total; hold once every 1 day for 4 weeks)

However, before the Japanese professor proposed the towel gripping exercise, many medical institutions in foreign universities had already studied the relationship between hand gripping training and lowering blood pressure. In 2004, researchers from McMaster University in Canada used professionally designed hand gripping equipment to test the changes in blood pressure of participants, and finally found that this exercise can effectively reduce systolic blood pressure, but there is no significant change in diastolic blood pressure.

Based on these studies, the American Heart Association (AHA) also listed other alternative methods of lowering blood pressure in addition to drugs and diet, including aerobic exercise (Class I, A), dynamic resistance (Class IIA, B) and isometric handlebars (Class IIB, C), among which Class I, Class IIA, and Class IIB refer to the level of evidence, with Class I being the highest; A, B, and C refer to the level of recommendation, with A being the highest, B being the second, and C being the lowest. The isometric handlebars here can be understood as hand grip training. Why can isometric handlebars lower blood pressure? The AHA's analysis is that isometric handlebar exercises may cause acute stimulation of metabolic reflexes to restore muscle blood flow, leading to reduced tissue oxidative stress, improved endothelial function, favorable changes in baroreflex sensitivity, and long-term autonomic balance. However, existing research results are inconsistent. Therefore, the clear mechanistic pathway is unclear.

It can be seen that the claim that holding a towel can lower blood pressure is not groundless. It is just that the special hand-gripping training in the study is simplified into a towel. It is precisely because towels are easy to obtain in daily life that they can attract more attention. However, it should be noted that even if the changes in blood pressure data in some controlled trials with hand-gripping training cannot be directly equated with lowering blood pressure. In the Canadian study mentioned above, researchers do not recommend that patients with hypertension in real life use this method, because the hand-gripping equipment in the experiment is relatively complex and is different from the handgrips and other appliances purchased daily. And from handgrips to household towels, is the effect discounted again?

Second, the reason why holding a towel lowers blood pressure is that it produces a large amount of nitric oxide, which is too taken for granted.

In addition to the attractive point of holding the towel in the hand, the popular saying also mentions that the reason why doing so can lower blood pressure is that when the hand holding the towel is relaxed, a large amount of blood flows into the originally tight blood vessels. At this time, nitric oxide begins to appear in the blood vessels, and nitric oxide can contract and expand blood vessels, thereby lowering blood pressure.

If holding a towel can produce nitric oxide, can clenching a fist also produce it? Can the contraction of blood vessels in other parts of the body besides the hands also produce nitric oxide?

Nitric oxide (NO) is a biological messenger molecule with a wide range of effects. In terms of cardiovascular and cerebrovascular diseases, it can relax vascular smooth muscle and dilate blood vessels. Commonly used nitrate drugs such as nitroglycerin and isosorbide mononitrate promote the production of nitric oxide in the body to dilate coronary arteries, improve myocardial blood supply, and treat angina pectoris. Viagra also increases the content of nitric oxide to increase blood supply and treat ED.

The nitric oxide in the blood is produced by vascular endothelial cells, and is generated by L-arginine in the cells under the catalysis of nitric oxide synthase. The key to the production of nitric oxide is not its "raw material" L-arginine, but its synthase nitric oxide synthase.

There is no evidence that holding a handgrip or a towel can increase the release of nitric oxide. Moreover, the half-life of nitric oxide is very short, which does not meet the requirements for lowering blood pressure. Lowering blood pressure requires lasting vasodilation, so although nitrates can increase the content of nitric oxide in the body, they are not used for antihypertensive treatment. Intravenous infusion of nitroglycerin is only a temporary medication for acute hypertension, and it must be continuously infused. Once the drug is stopped, blood pressure will rebound.

3. Handgrip training is a form of exercise, and other non-drug measures also have the effect of lowering blood pressure

If we go back to handgrip training, it is essentially a form of exercise. In addition to this, many other exercises can lower blood pressure. Not only exercise, many non-drug measures can also lower blood pressure.

The "Guidelines for the Prevention and Treatment of Hypertension in China" clearly states that the treatment of hypertension includes non-drug treatment measures and drug treatment measures. Non-drug measures are to improve lifestyles, and all hypertensive patients should improve their lifestyles.

Lifestyle intervention measures mainly include:

1. Reduce salt intake: It is recommended that the daily salt intake of each person be gradually reduced to below 6 g, and at the same time, increase potassium intake.

2. Reasonable diet: A reasonable diet means a balanced diet. The diet should mainly consist of fruits, vegetables, low-fat dairy products, whole grains rich in dietary fiber, and protein from plant sources, while reducing the intake of saturated fat and cholesterol.

3. Control your weight: keep your body mass index (BMI) less than 24; waist circumference: less than 90 cm for men and less than 85 cm for women.

4. Quit smoking and limit alcohol consumption: Do not smoke, quit smoking completely, avoid passive smoking; do not drink or limit alcohol consumption.

5. Increase exercise: moderate intensity exercise is recommended, with aerobic exercise as the main form and anaerobic exercise as a supplement, 4 to 7 times a week, each lasting 30 to 60 minutes.

6. Reduce mental stress: maintain psychological balance, social support, individualized intervention, psychological adjustment, etc.

Therefore, exercise can be beneficial for controlling high blood pressure. Of course, we should pay attention to those intense and confrontational exercises, which will make people's blood vessels dilate and adrenaline secrete in large quantities. At this time, blood pressure will not drop but will rise.

4. Are the natural blood pressure lowering methods circulating on the Internet reliable?

There are also articles introducing natural methods of lowering blood pressure, most of which are reliable, but a few are not.

1. Deep breathing: Relax yourself, increase blood oxygen content, reduce sympathetic nerve excitement, and help control blood pressure.

2. Listen to music and relax: It is reliable and can also help you relax yourself and reduce the excitement of your sympathetic nerves.

3. Reduce the workload: Reliable and relaxing leisure makes people relax, and its effect is similar to listening to music.

4. Walk fast: reliable.

5. Active treatment of snoring can also help lower blood pressure: It is reliable. Sleep apnea is one of the causes of high blood pressure. For many severe snorers, their blood pressure is controlled once the problem of airway obstruction is resolved.

6. Understand the salt content in food: Reliable, reducing salt is one of the most effective measures to control blood pressure.

7. Eat more foods containing potassium: It is reliable. Potassium ions can promote the excretion of sodium ions and help control blood pressure. Potassium supplementation is one of the blood pressure lowering measures recommended by the World Health Organization. Many vegetables and fruits contain a lot of potassium ions.

8. Eat more dark chocolate: unreliable, with no theoretical or practical basis.

9. Vitamin supplements: unreliable, with no theoretical or practical basis.

10. Drinking in moderation: This is very unreliable. Alcohol can cause blood vessels to dilate temporarily, lowering blood pressure, but then blood pressure rises in retaliation. Moreover, a large number of studies have confirmed that alcohol is harmful to the cardiovascular system, even in moderation.

11. Drinking tea frequently: It is unreliable. If it has any effect, it is the effect of water.

In fact, the purpose of controlling blood pressure is to reduce the occurrence of cardiovascular, cerebral, and kidney complications, and to reduce the mortality and disability rates caused by hypertension. Controlling blood pressure to meet the standard is the main means.

Non-drug measures have the effect of lowering blood pressure, but if non-drug measures cannot control blood pressure to the standard, please be sure to take medication in time.

Editor of this article: yhxi