May 17, 2024 is World Hypertension Day, and this year's theme is "Accurate Measurement, Effective Control, Healthy and Longevity".
The heart is the pump of blood throughout the body, the beginning of arteries and the end of veins. Therefore, the harm of sitting for a long time and immobility of the lower limbs to blood vessels and blood pressure is bound to affect the heart.
What is sedentary
Sedentary refers to the act of exerting energy ≤ 1.5 METs in a sitting or lying position while awake. MET, or Metabolic Equivalent, is an indicator of the relative level of energy metabolism during various activities based on the energy expenditure during a quiet, sitting position. 1MET is approximately equivalent to the energy expenditure (oxygen consumption) of sitting quietly, i.e. 3.5 millilitres of oxygen per minute per kilogram of body weight.
To put it more simply, sitting for 90 minutes can be considered sedentary, such as sitting at work, playing video games, watching movies, taking high-speed trains or planes, sitting and driving, etc. It can be seen that "sedentary people" abound.
A 2022 study published in The Lancet found that people who spent > 6 hours a day had a 26.7% increased risk of 12 chronic diseases, including cardiovascular disease, compared to those who spent < 2 hours a day sedentary.
Sedentary and deep vein thrombosis
Sitting for a long time leads to a decrease in metabolic levels, affects blood circulation, increases the risk of varicose veins in the lower limbs, and over time, there will be leg swelling, soreness, and some people will also have lower back pain.
Because everyone's physique is different, the degree of harm caused by sitting for a long time is also different. There is one situation that is more serious - deep vein thrombosis, which is at the top of the "sudden death list" of cardiology! Deep vein thrombosis of the lower extremities is also known as "card table syndrome" and is easily associated with sitting for long periods of time. People who sit for a long time and do not move their lower limbs have a slow return rate of venous blood and are prone to blood clots. If the blood clot flows back down the venous blood vessels to the inferior vena cava, right atrium, right ventricle, and then from the right ventricle into the lungs, once the blood vessels in the lungs are blocked by a large area of blood clots, the patient will have symptoms such as dyspnea, chest pain, and even death.
Sitting and high blood pressure
Although there are various tests and medications for hypertension, the most convenient and economical is lifestyle modification. Among them, avoiding sitting for long periods of time is very important to promote blood pressure and cardiovascular health.
Sitting for a long time can lead to abnormal endothelial function of blood vessels, causing vascular endothelial cells to release substances that can cause blood vessels to constrict and increase blood pressure. In addition, sitting for a long time causes poor blood circulation, and some metabolic wastes in the blood cannot be removed in time, which will also lead to an increase in blood pressure.
High blood pressure increases the load on the heart, especially the left ventricle. Long-term loading eventually leads to structural changes in the heart, with left ventricular hypertrophy likely to occur at first, just as athletes may experience muscle hypertrophy. The load brought about by high blood pressure in the heart is beneficial at first, but as the load increases, it will eventually decompensate. Long-term hypertension can also aggravate atherosclerosis, induce coronary heart disease, and lead to serious complications such as angina, myocardial ischemia, myocardial infarction, heart failure, and renal insufficiency.
Be sure to "get moving"
Nowadays, the way people live and work has changed a lot, and many tasks need to be done at the desk for a long time, and they are increasingly inseparable from computers. Research statistics show that adults usually sit for 7~11.5 hours a day, and 18.8% of them not only do not like to exercise, but also sit for more than 6 hours a day. Sitting too much time increases the risk of cardiovascular disease. A number of studies have proposed that "less sitting, more activity" should be used as an important method to prevent and manage cardiovascular diseases.
Exercise can increase the basal metabolic rate, so that the metabolism of cells, tissues and organs throughout the body is significantly increased, reaching a level higher than that of sedentary state, thereby reducing the risk of triglyceride levels, blood viscosity, vascular plaque formation and various cardiovascular events.
By "interrupting" sedentary periods by making small movements at regular intervals, people who sit for a long time are able to improve blood vessel function and blood flow in the lower limbs and protect the blood vessels in the legs. The blood circulation throughout the body becomes smooth and light, which is beneficial for patients with high blood pressure and those at high risk. In addition to ensuring that you spend active time each day, you should also reduce the total amount of time you sit, which means avoiding "physically active but sedentary" situations.
Adults tend to spend a lot of time sitting throughout the day. Specifically, in the 16 hours other than sleeping, a retiree who sleeps 8 hours a day and does not work spends a total of 14.5 hours sitting (eating, chatting, watching TV, and reading) in the 16 hours other than sleeping, although the cumulative activity time is 1.5 hours. According to the physical activity guidelines, although the level of activity is up to the standard (considered to be physically active), most of the time is spent sitting except for sleeping.
The "Healthy China Action (2019-2030)" encourages individual workers to pay attention to relieving muscle tension through stretching activities and other means, such as getting up every 1~2 hours to rest, bending over, lifting shoulders, and doing chest expansion exercises.
The author recommends a simple and effective "ankle pump exercise", which is like stepping on a sewing machine. This is done by hooking the toes upwards so that the toes are facing you for about 10 seconds, then extending the toes down for about 10 seconds, and then flexing and extending the ankle repeatedly.
Of course, lifestyle changes should be gradual and choose the type and intensity of exercise that suits you. If conditions permit, you can carry out body composition analysis, cardiopulmonary exercise test, etc., and gradually exercise under the guidance of science, lighten up and become healthy.
Text: Wang Fang, Chief Physician of the Department of Cardiology, Beijing Hospital
Editor: Liu Yang, Li Shiyao
Proofreading: Yang Zhenyu
Review: Guan Zhongyao, Xu Bingnan
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