If there are many people around you, even if most people are quarantined at home or wear masks, the infected person may still transmit the virus to others, otherwise so many people will not be infected.
So, does it mean that the invisible viruses that are exhaled by infected people are floating in the air from time to time?
Is it safe for runners to run outdoors?
Today we will explain this issue in detail.
How does the new coronavirus spread?
1, contact transmission
Touch the surface of a contaminated object, such as the intermediate animal host, and then touch the mouth and eyes with dirty hands, so that the virus can enter the body fluids of the human body. This is why people have a high chance of infection due to sexual transmission.
Give a typical example☟
Handler of the virus wiped his nose and quickly touched the bus handrail he was riding. In a short period of time, you also touched the handrail of the virus carrier. This is when your eyes were itchy and rubbed your eyes with your hands. At this time, you have a higher risk of being infected.
Therefore, frequent hand washing is the most important measure for contact transmission.
By washing your hands, you can effectively rinse or eliminate viruses. At the same time, don’t be used to touching your mouth, eyes, nose and other parts with your hands.
2, droplet transmission
Drop transmission mainly utilizes human mobility, that is, as long as people pass through the space where droplets flow, they may be infected.
. For droplet transmission, masks are the most important and effective protective measures. Viruses do not exist alone in the air. Viruses that exist alone are more likely to die. Droplets are the main vector of the virus, and masks have a clear effect of blocking droplet infection.
In this sense, positive infections should wear masks more than the general public because they are potential virus spreaders. They wear masks to effectively block droplets transmitted by cough and reduce the spread of the virus through droplets.
According to research data, when we sneeze or cough, the droplets produced quickly spread like a cloud, which can bring bacteria or viruses to a distance of about 2 meters.
3, aerosol spread
According to the currently being implemented, the new coronavirus is transmitted through aerosols in a relatively closed environment.
Sneezing is a violent atomization process. The airflow speed of sneeze is very strong, reaching 50 meters per second, comparable to a level 15 typhoon. This picture shows the trajectory of droplets after sneezing with high-speed cameras.
sneezing high-speed photography image
green represents what we usually call droplets, with strong inertia and a range as far as two meters, but then quickly settled to the ground. The red part is a small droplet of several microns. Due to its low moisture content, the moisture evaporates under the action of air friction and becomes particles of micron-scale, also known as droplet cores.
droplet cores are very light and very small in weight, so they can be suspended in the air and drift around with the air. They belong to the category of aerosols, and the droplet cores are also aerosols.Does the virus in
Before inactivated, does it mean that it can spread to a longer distance and infect more innocent people?
The propagation of aerosol is stronger than contact infection and droplet infection. This exists. If you do not contact patients at close range, in fact, the risk of droplet transmission and contact transmission is very small. However, due to the existence of aerosol, the possibility of air transmission is increased. For example, the distance of contact transmission is zero and the distance of droplet transmission is about 2 meters, so the distance of aerosol transmission may be larger.
But don't ignore one thing, the further the aerosol spreads, the smaller the chance of the virus survival. It is unscientific to say that aerosols can transmit viruses arbitrarily from space distance, and we cannot fall into a stubborn debate.
Therefore, in the "New Coronavirus Pneumonia Prevention and Control Plan (Ninth Edition)", the new coronavirus is transmitted through aerosols in a "relatively closed environment", and the risk of infection due to aerosols in an open environment is minimal.
Is the virus like a ghost
everywhere?
NO!
Although the possibility of droplet transmission mentioned above does exist clearly, the public cannot imagine that viruses float in the air at any time like PM2.5, everywhere, and will enter the human body if you are not careful.
Because droplets will not always exist permanently, the spatial degradation and natural selection effects of the natural environment will effectively resolve droplets. The main mission of the
virus is to replicate, which is to copy its genetic material in the host cell and then spread it.
has only one purpose of leaving the host cell - it is to spread to the next host, so the virus can be transmitted through droplets and contact, and the shorter the time, the higher the transmission efficiency. The aerosol containing the virus can indeed survive in the air for a period of time, because the protein envelope outside the virus can ensure that its genetic material RNA exists in the air for a certain period of time.
But if it keeps floating in the air, it will generally cause damage to genetic materials due to dryness, lack of water/ultraviolet irradiation/oxidation, etc.
There is no evidence that this time, coronavirus can survive in a dry environment for a long time.
In other words, the virus will not float away independently from the vector (the so-called vectors include blood, body fluids, saliva, etc.). In other words, the public imagines that there is virus everywhere in the air and there is nowhere to escape is impossible.
droplets are sprayed out through the oral cavity, and the distance reached is limited after all. After the moisture in the droplets evaporates, it is basically difficult for the virus to survive for a long time, and the virus degrades and dies at any time.
Therefore, in general, the virus density is very low or does not exist in air circulation places. In addition, potential virus carriers are also likely to have higher virus density, because they may sneeze or speak at any time and droplets will spread.
The essential reason is that the more people there are, the more potential virus carriers there will be.
Please remember that there is no separate virus in the air!
In addition, the coronavirus is more sensitive to heat. It can lose its infectivity by 56 degrees for 30 minutes. The coronavirus is sensitive to organic solvents and disinfectants. 75% alcohol , ether , chloroform, formaldehyde, chlorine-containing disinfectants, peracetic acid and ultraviolet rays can all inactivate the virus.
Running in outdoor open places is safe
According to the above analysis, even under the current circumstances, the possibility of infected people being infected with aerosols or droplets is very slim.
Not only brings all-round benefits to the body, exercise can also effectively improve mental health. Especially when the epidemic causes general anxiety among people, exercise can have a good effect of alleviating adverse emotions.
And bad emotions themselves will lead to a reduction in the human body's resistance, so exercise plays an irreplaceable and important role in balancing the immune system and enhancing the human body's resistance.
We all know that the human body has certain resistance to viruses, and this resistance may play a very important role during the epidemic. Exercise can significantly improve the human body's resistance. Therefore, when the epidemic is epidemic, we should pay more attention to physical exercise.
Of course, you must be stubborn. I said that when I was running, a person passed by me. This person was Yangxin infected or asymptomatic infected person . His breath was caught by me. Will there be infection?
As early as 2020, the technology company Ansys released a video to remind people who are running outside to pay attention, even if they are 2 meters away from the carriers of the new coronavirus, you may be infected.
video shows that the risk of side-by-side movement is lower than the risk of vertical following, because it depends on the direction of droplets infected with the virus.
In side by side, when a person coughs or sneezes, most droplets fly behind the runner rather than next to him. Those droplets will hang in the air.
If you are more than two meters behind him and just run over, you will directly crash into the droplets without enough time for them to spread.
The same situation above, if you do not run directly behind him, but are obliquely behind and maintain social distance, it is relatively safe.
So, choose an open place and keep a safe distance of 2-3 meters from others. Even if the passerby you pass by is a virus carrier and is in the detoxification stage, the risk of your infection by aerosols or droplets is very low.
Once again it is emphasized that you don’t have to wear a mask when running
Three years have passed, and this should become a consensus: that is, do not wear a mask when running.
First, wearing a mask to hinder breathing and increase the burden on the heart and lungs. Secondly, the ventilation volume during exercise increases significantly, and the effect of water vapor will cause the mask to be wet very quickly, and the protective effect of the moist mask is greatly reduced.
versus the impact of running without wearing a mask, wearing a normal mask and N95 mask on the heart and lung system
Figure 1 represents the actual ventilation volume, the so-called ventilation volume refers to the total amount of gas actually entering or out of the lungs per minute.
As the speed increases, the ventilation volume increases significantly, but running with a mask will lead to a significant reduction in ventilation volume, that is, a decrease in gas intake. This is related to the significant increase in ventilation resistance caused by masks, and wearing an N95 mask will further reduce the ventilation volume compared to ordinary masks. At the pace of
700 and 600, the ventilation volume decreases by about 15%, while at the pace of 500, the ventilation volume decreases by nearly 20%, that is, the faster the speed and the more it needs to increase the ventilation volume, the ventilation volume decreases more significantly.
Figure 1 Comparison of ventilation volume for wearing masks at three speeds (liters/min)
Oxygen intake represents the body's blood circulation through the heart and lungs blood circulation. From the actual oxygen intake, the oxygen intake increases with the speed of speed. However, compared with not wearing masks, the oxygen intake decreases significantly, and the oxygen intake decreases most significantly when the N95 mask is inhaled.
In other words, wearing a mask, especially N95 mask, makes the body unable to inhale enough air, insufficient oxygen supply, and insufficient oxygen supply, so the natural oxygen utilization will have no source, which aggravates the body's lack of oxygen.
When running with N95 at 500 pace, the oxygen intake only reaches the level of running at 700 pace without wearing a mask, and the actual oxygen intake at 500 is logically greater than 700.
Figure 2 Comparison of oxygen intake for running with masks at three speeds (ml/kg/min)
It can be seen from Figure 3 that as the speed accelerates, the heart rate of increases. At the same time, the heart rate of is significantly higher than that without a mask when running with masks.
This point is also logically clear. Running with a mask, there is insufficient oxygen intake, and the blood flows through the lungs is insufficient oxygenation, but muscle exercise requires an increase in oxygen supply. At this time, the heart can only make up for the insufficient oxygen content in the blood by accelerating the beating, that is, wearing a mask artificially creates an oxygen-deficient environment.
However, the increase in heart rate will significantly increase the work burden of the heart and lungs. At the same time, the heart beats desperately and requires blood oxygen supply, but the blood oxygen supply is not so sufficient, and the heart is also in a relatively hypoxia working state, which aggravates heart fatigue.
Figure 3 Comparison of heart rate for running with masks at three paces (times/min)
summary
is currently in a relatively epidemic period. In a sense, if you run a group to make an appointment, it is not very suitable at the current stage, because not only are the members of the running group gathered, but they often gathered together during the running process. The risk of aerosol transmission of is greater than that of individual running, which may increase some unfavorable risks at this time.
Therefore, it is recommended that the running team can currently suspend routine running and instead run by runners.
Coronavirus does not float in the air everywhere like PM2.5. You will suck it in if you are not careful. It is safe to run in an open place.
again emphasizes:
Don’t have to wear a mask when running, don’t run when wearing a mask!
The important precautions you should take when exercising are to maintain a physical distance of at least one meter from others.
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