Afternoon or evening is a good time for outdoor sports for three main reasons: First, the body's biological clock is at its climax in the afternoon, when the physiological function is at its best-human endurance is enhanced, muscle temperature is high, blood viscosity is the lowest, and joints are the most flexible: in a day, the maximum oxygen intake of people is around 6 pm; The most stable time of human heartbeat and blood pressure is from 17 to 19. According to the research of British physiologists, from 4 pm to 7 pm, the human body has the highest adaptability to the external environment and the best nerve flexibility. Therefore, choosing to exercise in the afternoon or evening can maximize the potential and adaptability of the human body and achieve the purpose of fitness. Second, the air quality is the best in the afternoon. Third, exercise in the afternoon is the best way to sleep at night. British medical scientists have found that people who exercise in the morning sleep almost as much at night as usual, while those who exercise in the afternoon sleep much better at night than usual.
The reasons for not exercising in the morning are as follows:
First, the lowest time of the human biological clock is the early morning.
In the morning, people have the lowest body temperature, the slowest pulse and the worst physiological function. If you exercise at this time, it is equivalent to suddenly entering more intense exercise from a state of rest or not awakening. This is a kind of "rash advance", which is not worth the loss. However, the muscles and joints of the human body quickly enter a state of tension and strength from a relaxed state, and it is difficult to adapt for a while.
Second, the most dangerous moment for the human body is early morning.
According to the statistics of the World Health Organization, 60% people in the world die in the morning. The early morning is not only the peak of heart attack, but also the high incidence of sudden cardiac death. Exercise in the early morning, especially when the amount of exercise is large, is equivalent to suddenly increasing the burden of cardiovascular and cerebrovascular diseases when the human body is at its most dangerous.
In the vast majority of people with normal blood pressure and about 70% patients with hypertension, the blood pressure at night is about 10% lower than that during the day. The specific situation is that people's blood pressure drops at night, and it drops to a minimum around 2 ~ 3 am. After getting up in the morning (6 o'clock), blood pressure rises sharply, reaching or near the peak at about 8 o'clock to 9 o'clock. At this time, the blood pressure is even 40 to 50 mm Hg higher than at night. This phenomenon is medically called "morning hypertension (peak blood pressure in the morning)". This is a dangerous moment for patients with hypertension, because at this time, patients' sympathetic nerves are excited, their heart beats faster and their blood pressure rises. In addition, due to not drinking water all night, the patient lost a lot of water through breathing and the blood viscosity increased. Moreover, if there are hypertensive patients with atherosclerotic plaques, the plaques will easily rupture at this time, leading to myocardial infarction and cerebral infarction.
Studies have shown that the risk of stroke in patients with hypertension in the morning is three times that at other times; The incidence of myocardial infarction at 9 am is three times higher than that at 9 pm; The peak of sudden cardiac death is also from 9 am to 12 am. Therefore, the one-day plan to control blood pressure lies in "morning". Getting up and exercising in the morning will undoubtedly increase the possibility of accidents.
Third, the worst time for air is early morning.
Meteorologists say that the fresh air in the morning is a "false sense". This is because people emit a lot of carbon dioxide and other waste gases overnight in the house, especially in winter, when the doors and windows are closed, the air is dirty, the air outside the house is better than that inside, and the temperature is lower than that inside, so when you go out in the morning, you will feel the air is fresh. But the fact is that the outdoor air is the worst in the morning.
In the morning, after a night of metabolism, plants absorb oxygen and exhale a lot of carbon dioxide, which increases the concentration of carbon dioxide in places with many trees and flowers; Various harmful substances, such as nitrogen oxides and hydrocarbons, produced by coal burning and automobile exhaust emissions gather in the air, and breathing these dirty air will have harmful effects on the human body. After the sun comes out, these pollutants will be diluted and decomposed in the air, and the air quality will be relatively better. So generally speaking, it is not advisable to do morning exercises before the sun comes out.
Fourth, it is easy to fog in the morning.
Fog is easy to appear in the morning in autumn, winter and spring. Due to the stability of atmospheric stratification, it is difficult to exchange and diffuse air in foggy days, which will aggravate air pollution. According to the measurement, the proportion of various harmful substances such as acid, alkali, salt, amine, phenol, dust and pathogenic microorganisms in fog drops is several times higher than usual. People who stay in the fog for a long time will inhale harmful substances, consume nutrients, affect oxygen supply, cause internal injuries, induce or aggravate illness, cause chest tightness, dyspnea and other symptoms, and in severe cases cause rhinitis, pneumonia, tracheitis, conjunctivitis and so on.
For those who have the habit of doing morning exercises, we should pay attention to three points: first, the amount of exercise in morning exercises should not be large; Second, it is best after 9 am; Third, drink some water before exercise to prevent blood viscosity and hyperlipidemia, as well as sweating and dehydration during exercise.