Hippocrates, the father of medicine, once said:
sunlight
air
water
sports
This is the source of life and health.
Exercise is a good medicine for everything.
Especially in the current epidemic situation.
It is very necessary to have a healthy body.
Everyone knows that life lies in exercise, but few people realize that maintaining an active life is actually something that most of us can do, and it is also the top priority for us to improve or maintain health. Regular exercise can not only reduce the risk of heart disease, stroke and diabetes, but also prevent some cancers, improve mood, strengthen bones and muscles, increase vital capacity, reduce the risk of falls and fractures, and help maintain a healthy weight. And these are just the benefits of some sports we are familiar with.
In the past few years, the research in this field has developed rapidly, and the research on the health benefits of exercise has also been deepened. Among other benefits, physical exercise seems to improve brain function (especially the ability of attention, organization and planning), relieve some individuals' symptoms of depression and anxiety, and enhance the immune system's ability to detect and resist certain cancers. In addition, researchers are no longer limited to describing the obvious health benefits of regular physical activity, but begin to study in detail the positive effects of physical exercise on atherosclerosis patients and diabetic patients at the cellular and molecular levels.
Many projects study how physical exercise affects various human systems (cardiovascular system, digestive system, endocrine system and nervous system, etc.). It is found that most of the health benefits come from the moderate improvement of various physiological activities by physical exercise, rather than the great changes of a few physiological processes in specific cells and tissues.
The researchers also found that not only triathletes can benefit from sports. Twenty years ago, preventive medicine experts almost only focused on the health benefits of high-intensity exercise. Nowadays, they also begin to emphasize the benefits of regular moderate-intensity exercise. In two large-scale research projects "Nurses' Health Research" and "Women's Health Initiative", Manson, one of the authors of this paper, participated in a comparative study on the health benefits of moderate and high-intensity exercise. Based on these research data, the latest "American Sports Guide" (published in 2008) advises the public to do moderate-intensity exercise for 30 minutes at least five or more times a week (for example, brisk walking), or 75-minute high-intensity exercise (for example, jogging) once a week, and at least 30 minutes of muscle strengthening exercise twice a week.
Further careful analysis of these findings can help us understand how physical exercise unconsciously protects our bodies and keeps them functioning normally.
be effective immediately
In order to fully understand these latest findings, let's first understand how the body responds to increased physiological needs. For different individuals, physical exercise may mean completely different sports. From snowshoeing to swimming and walking on the beach, there are various forms of physical exercise and the intensity of exercise is also different. Aerobic exercise can significantly increase the oxygen demand of muscles, which requires high-intensity work in the lungs. Its health benefits are the easiest to understand. But other persistent exercises (such as weight lifting or balance exercise) also have their advantages.
Scientists have developed a strict method to measure the intensity of aerobic exercise in the laboratory. An effective way to measure exercise intensity more economically outside the laboratory is the talk test. When physical activity reaches a moderate intensity, your heart starts to speed up and your breathing starts to get heavier. As long as you can talk or recite poems while exercising, the exercise intensity is still medium. If you can only say one or two words at a time when you exercise, you are doing high-intensity exercise. If you can still sing while exercising, then your exercise intensity is very slight.
Whenever the human body starts to speed up the rhythm, the nervous system will adjust all the organs of the body to the corresponding motion state. At first, a person may notice that his perception becomes more acute, his heartbeat and breathing begin to accelerate, and his body begins to sweat slightly. At this time, the blood flow of non-essential organs such as gastrointestinal tract and kidney began to decrease. At the same time, the blood vessels in exercise muscles begin to expand to ensure sufficient oxygen supply in muscle tissue and achieve the best working condition.
Oxygen entering muscle cells will further penetrate into an organelle called mitochondria, which use oxygen to make energy for cells. The human body digests and absorbs large food particles and breaks them down into glucose molecules, which are used as the basic fuel in the process of mitochondrial productivity. In mitochondria, oxygen promotes the effective oxidation of glucose molecules. Under aerobic conditions, the productivity of glucose molecules in mitochondria is nearly 20 times higher than that under anaerobic conditions.
The body first uses glucose molecules in the form of glycogen in liver and muscle tissues. However, with the progress of exercise, the available glycogen in the body is quickly exhausted, and triglyceride (a kind of fat) molecules become the main energy source. All these oxidation reactions in the body will produce some by-products, such as lactic acid and carbon dioxide. These by-products will penetrate into the blood from muscle tissue and flow to all parts of the body. The increase of these by-products will trigger a series of biochemical reactions in the brain, lungs and heart, and remove these wastes from the body more effectively and easily.
Once physical activity becomes a habit, the benefits of exercise to the body really begin to accumulate slowly. The body began to adapt to the various physiological needs of increased physical activity, the individual's endurance improved, and the body became healthier and healthier. For example, with the deepening of breathing, the amount of oxygen processed by the lungs increases, and the amount of blood pumped by the heart also increases. These adaptive physiological reactions usually occur within a few weeks after the individual's physical activity reaches or exceeds the recommended standards of the US government. These physiological reactions will also cause some physiological changes in the human body and improve the individual's health for a long time.
Molecular change
About the influence of physical exercise on all aspects of human body, from the influence on major organ systems to the influence on various gene activities, a huge amount of research data has been accumulated so far. The chart "Benefits of Exercise" lists some main research conclusions. However, we are concerned about some newly discovered mechanisms in this paper, which can help explain why physical exercise can expand our cognitive ability, improve our ability to control blood sugar and strengthen our cardiovascular system. Among the benefits of exercise, these changes have the greatest impact on the quality of our daily life.
Athletes have long found that exercise can improve mood and mental health. However, it was not until 2008 that scientists were finally able to directly measure the so-called "runner's high"-a kind of pleasure that individuals feel after long-term exercise. They found that during long-distance running, people's brains will release more endorphins (an opioid hormone that can produce pleasure), which will act on the areas of the brain that control strong emotions. Previous studies only found the increase of endorphin content in blood, but not related to the changes in the brain. )
Recently, researchers began to pay attention to the brain chemical changes caused by exercise and how they can improve people's attention, thinking and decision-making ability. On 20 1 1 year, a rigorous scientific experiment (that is, a randomized controlled experiment) was conducted on 120 elderly people aged 60-70. The results showed that exercise increased the volume of hippocampus in the brain. The author of this research paper mentioned that the part of hippocampus affected by exercise is actually the part that controls people's memory of familiar environment, and it is also one of the few areas in the brain that can produce new nerve cells (at least in rats). Newborn nerve cells are thought to help individuals distinguish between similar and different things. Animal studies further show that exercise can improve the level of brain-derived neurotrophic factor (BDNF), which is a molecule that induces the growth of newborn nerve cells.
At present, many scientific studies are challenging our understanding of preventing heart disease through exercise. At first, scientists thought that daily exercise could reduce the risk of cardiovascular diseases, mainly by lowering blood pressure, reducing the content of low-density lipoprotein cholesterol molecules (bad cholesterol) and increasing the content of high-density lipoprotein cholesterol molecules (good cholesterol). This conclusion is actually only partially correct. Exercise can indeed significantly lower the blood pressure of some people, but for most people, the benefits of exercise are relatively small. Moreover, it takes several months to increase the content of HDL cholesterol in the blood through exercise (especially resistance exercise such as weight training), even if it is only a few percentage points.
Further research shows that the effect of exercise on low-density lipoprotein cholesterol is more important to change the characteristics of this molecule than to reduce the level of this molecule in the blood. Strictly speaking, low-density lipoprotein is different from cholesterol. It is actually a carrier of cholesterol in the blood, just like a truck carrying goods. The lipid component of cholesterol makes it insoluble in the water environment of blood, so it must be wrapped in water-soluble substances. Low-density lipoprotein particles also come in many different sizes, just as the cargo can be a van or a big truck.
In the past few years, more and more scientists have found that low-density lipoprotein with smaller molecules is particularly dangerous. For example, they can easily release electrons, rampage through blood vessels and destroy other molecules and cells (think of it as a broken van driven by crazy drivers). On the other hand, LDL with larger molecules is much more stable. It flows with the blood and won't hit anything (just like a big truck driven by a professional driver).
Current research shows that exercise can increase the number of larger and safer LDL, while reducing the number of smaller and more dangerous LDL. Exercise can increase the activity of lipoprotein lipase in fat and muscle tissue, thus changing the ratio of larger and smaller low density lipoprotein. If two people exercise differently, even if their blood cholesterol levels are the same, their risk of heart disease will be very different. There may be a large number of low-density lipoproteins with small molecules in sedentary people, while people who exercise regularly may have a large number of low-density lipoproteins in their blood. Even if the cholesterol levels of these two people are exactly the same, the risk of heart attack of the former may be several times that of the latter.
Regular exercise can also have a positive impact on another important component of blood sugar. Whether at rest or during exercise, the liver, pancreas and skeletal muscles (the muscles that turn the head, arms, legs and body) usually work together to ensure that all parts of the body get the sugar they need. Exercise will undoubtedly increase the human body's requirements for skeletal muscle, which needs more glucose to meet these requirements. In the long run, exercise will also make muscle fibers use glucose more effectively, thus making muscle fibers stronger.
When the body signals that it needs more energy, the liver will immediately release sugar molecules into the blood, while the pancreas will secrete insulin, instructing cells to absorb the increased glucose in the blood. You may think that this process may lead to a sharp change in blood sugar level after meals or exercise, but in normal people, the blood sugar level has been controlled within a limited range of 70 ~ 140 mg/dl (fasting blood sugar is maintained below 126mg/dL). The blood sugar level must be kept above 70mg/dL, because glucose is the main energy source of the brain, and the brain is very sensitive to the change of blood sugar concentration. Although extreme hypoglycemia may lead to coma and death within a few minutes, it is equally important to avoid long-term hyperglycemia from a physiological point of view. Generally speaking, too much sugar in the blood can easily worsen the physical condition and lead to premature aging of cells.
When physical exercise becomes a daily habit, the sensitivity of human muscle tissue to insulin will increase. This means that the pancreas does not have to work so hard to keep blood sugar stable in the body; Low concentration insulin can achieve the effect that high concentration insulin can achieve in the past. This is of special significance to patients with type 2 diabetes, because it is difficult for them to maintain normal blood sugar levels, which is largely due to their tolerance to insulin. Moreover, insulin can also promote the proliferation of cells (that is, quickly produce new cells), so high concentration of insulin will increase the risk of breast cancer and colon cancer.
Recent studies have found that physical exercise can also promote another way to absorb glucose, which is independent of insulin. One more method to remove glucose from blood and transfer it to muscle cells without relying on insulin may open up a new direction for the treatment of diabetes.
Interestingly, diabetics who do many different exercises seem to benefit more from exercise. Two large-scale randomized controlled experiments found that the combination of aerobic exercise and resistance training is more helpful to control human blood sugar level than single exercise. However, in the first study, because of its experimental design, it is impossible to determine whether individuals who participate in aerobic and resistance training benefit more than those who participate in single exercise, because of the relationship between the two exercises at the same time or because the total time of exercise is longer. Church, one of the authors of this paper, decided to launch a second experiment to solve this problem. He divided 262 sedentary diabetic patients into four groups: aerobic exercise group (walking on a treadmill), resistance training group (rowing in a sitting position, leg press, etc. ), comprehensive group (aerobic exercise combined with resistance training) and control group.
During the nine-month experiment, the physical activity time and intensity of each experimental group were almost the same (about 140 minutes per week). All participants in the experiment reduced their waistlines, and both groups became healthier after aerobic exercise. However, the content of HbA 1c in the blood of individuals in the comprehensive group decreased significantly-HBA1c is a protein index reflecting the average blood sugar level in the past few months. The superposition effect of the two kinds of exercise suggests that aerobic exercise and resistance training have different influence mechanisms on the body. At present, researchers in Pennington Biomedical Research Center and other places in the United States are actively exploring the reasons.
Exercise can also strengthen muscle tissue by promoting the formation of prolific mitochondria. Daily physical exercise will make muscle cells produce a kind of protein called PGC- 1α, and this protein will prompt cells to produce a large number of new mitochondria. The more mitochondria in cells, the more cells can use glucose, thus increasing muscle strength and resisting muscle fatigue.
The harm of sedentary life
Since moderate-intensity exercise is so good for your health, you might think that everyone will tie their shoelaces and start going out to exercise. But many Americans don't even get moderate-intensity exercise for one and a half hours or more than five times a week. Only 52% of American adults meet the aerobic exercise guidelines in the American exercise guide, and only 29% will complete 30-minute muscle training twice a week. Only 1 in every five Americans meets the standards of aerobic exercise and resistance training recommended by American sports guidelines.
It is not easy to change people's habit of sedentary and not exercising at once, so scientists began to study whether lighter and shorter exercise is also beneficial to health. They hope that positive research results will encourage those who curl up on the sofa all day to move as much as possible. So far, the preliminary research results show that even the smallest amount of daily exercise can help to prolong life. In 20 12 years, the data of 655,000 American adults in six studies during 10 years were analyzed. The results show that individuals who spend only 1 1 minute on leisure activities live longer than those who are inactive 1.8 years. It is true that those individuals who meet the exercise standards live longer, and their life expectancy is 3.4 years longer than that of inactive individuals. Those who do 60-90 minutes of physical activity every day have a life expectancy of 4.8 years longer than those who are inactive.
Even the least amount of exercise is beneficial. Moreover, a comprehensive review of sports research so far shows that most people will benefit from increasing exercise. For example, if they generally exercise lightly, they should exercise moderately, or if they generally exercise moderately, they should increase their strenuous exercise for a short time. The worst news for knowledge workers sitting in the office today may be that even if you are doing a little intensive training, it is harmful to sit for more than six hours in your spare time every day. Whether this is the cause of sitting posture itself or the lack of exercise caused by sedentary is still unknown.
In view of more and more evidence that sports activities are beneficial to health, its enlightenment is obvious. Regular long-term exercise-keeping the intensity level within a safe range-needs to become everyone's daily habit, and the whole society needs to form an exercise atmosphere. Exercise should be as common as people jumping into cars as soon as they go out now.
We strongly recommend that doctors and other health care workers write "regular exercise" on their prescriptions when people come for routine check-ups. In addition, in today's society, people often sit for a long time, but there are also some behavior patterns. The change of public health movement and urban design is conducive to improving people's level of sports activities. We suggest further study of these factors.