Does exercise temporarily weaken your immune system?

Some people think that question is silly. We have been taught since childhood that exercise is good for health. Exercise strengthens the immune system and resistance. Being active will help you combat all germs, including the new SARS-CoV-2 virus, which is causing the Covid-19 epidemic.

However, try to remember the first day you went to the gym or ran 5 km and, like many people, you had to go home with a dry throat and sniffed nose. Then it looks like you got sick from exercise.

An adult since the 1980s, which means they are now under 40 years old, can tell you: Do not practice quickly, translating Covid-19 is not a good time for beginners sex will weaken the immune system in a short time.

Remember the dry sensation in your throat and wondered if it was real or not? Does exercise really temporarily hinder your body's immunity?

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' Open window ' hypothesis: When immune cells are missing from the blood stream

John Campbell, a professor of health sciences at the University of Bath in the UK, and the author of a comprehensive review of influential studies on exercise and the immune system, said:

In the 1980s, there were actually studies reporting a strange phenomenon, that marathon runners were very ill with the symptoms of an infectious disease within days to weeks of their race.

Starting with this study, a hypothesis has been formulated that when your body is overloaded by exercise and sports, your immune system is overloaded, making infectious pathogens more vulnerable. This hypothesis may be especially true in case you are a beginner and often overworked on the first day.

Some studies suggest that a single hard workout also temporarily reduces our immune responses soon after, putting us at higher risk for opportunistic infections after a workout. .

This ability is called open-window theory, and it has been reinforced by several experiments on animals and humans showing that after each exercise session, immune cells will spill into their bloodstream. me, but then they suddenly disappeared.

Some researchers tested the volunteers' blood just before, during and immediately after training and found missing immune cells. They thought that they might have been killed because the exercise intensity was too heavy.

The disappearance of a large number of immune cells seems to leave a window open for opportunistic pathogens to invade and infect the body, before new immune cells recover.

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Virtual solution: Exercise basically does not weaken but also strengthens the immune system

The truth is that the open window hypothesis only exists for a period in which some researchers make a mistake. More thorough studies have confirmed that, because your blood has fewer immune cells, your body will be more vulnerable to pathogens.

In a highly sophisticated experiment on rats, the researchers marked some of their immune cells with a fluorescent dye, and then forced the mice to run until exhausted. They tracked the luminescent cells in the blood of mice and saw their numbers soared and then plummeted, just like the model previous studies had found.

But the later findings were really interesting. After exhausting exercise, only a few immune cells of the mice died. The majority of other cells disappear in the blood stream, because they have traveled to the lungs, intestines and the most vulnerable organs of rats.

They go there to protect their bodies from opportunistic pathogens. After a few hours on duty in these organs, immune cells have returned to the bloodstream. They are not diminished.

Similarly, in a study published in 2019, scientists injected pathogenic bacteria into two groups of mice. One is the sedentary mouse, and the other is the mouse just run tired.

As a result, mice that run to fatigue still fight bacteria better, since immune cells in their blood are more concentrated and cling to pathogens. In the blood of lazy mice, immune cells tend to be more dispersed and do not clump together to fight off bacteria effectively.

But why did you sniff after the first workout?

Going back to research on marathon runners, the scientists who made it also made mistakes in experimental design. They rely solely on the athlete's self-diagnosis report on respiratory symptoms or stuffy nose.

A number of subsequent studies have examined the results of this study, conducted based on objective monitoring of marathon runners after races showing the fact: very few of them are infected. Respiratory. They only have symptoms such as illness due to airway irritation during the race, or other non-infectious conditions.

The same may be true for beginners who exercise early on. At that time, people often exercise too much and do not adequately replace water. This can cause your throat and airways to dry out, which in turn gets more irritated and causes symptoms such as sore throat and runny nose.

However, subsequent studies determined that marathon runners and other endurance athletes had fewer sick days a year than the average person, implying that their immune systems were not overload due to exercise but also strengthened.

Since then, numerous studies in both humans and animals have supported this new hypothesis. For example, a series of 2005 experiments with mice showed that if mice jogged gently for about 30 minutes a day for several weeks, they were more likely to survive under a fatal exposure to the flu germ. than untrained mice.

Therefore, exercising will really help you to be healthier, not create opportunities for germs to invade and make you sick.

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Do not overdo and be vigilant about gym surfaces

Studies that support the 'open window' theory of the immune system and exercise have all been dismissed. Instead, the latest science shows that there is no reliable evidence that direct exercise increases the chance of getting any virus, Professor James said.

Therefore, it is safe for people to exercise and start exercising in the Covid-19 epidemic. Exercise can help you reduce your risk, he adds.

However, there are two things you need to pay special attention to. Those are two situations that can make you sick when you exercise.

Firstly, you should not overdo it. A 2005 study of mice and influenza viruses found that exhausted mice were more susceptible to symptoms with symptoms that lasted longer than mice that only ran moderately, although the difference was small.

To be fair, when you're exercising too hard for too long, especially in beginners, it can have temporary negative effects on the immune system, Jeffrey Woods, a professor of public health at the University of Illinois at Urbana-Champaign, said.

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Dumbbells, rails, slabs, and treadmill handles are the most likely pathogens to spread germs in a gym.

The second thing to keep in mind when exercising during the epidemic season, is that the gym itself can also become a high-risk infection site. A 2019 study found that treadmill, bar, plate and handle on treadmill are the most likely pathogens to spread germs in the gym.

Therefore, you need to consider when you intend to go to the gym. If you feel unwell, you should avoid exercising. If at the gym there is a person who has symptoms of coughing, sneezing, it's best to keep your distance from them.

Don't touch your face at the gym and wash your hands before and right after you finish your workout. You can also ask the gym to regularly wipe disinfectant on high contact surfaces to keep members safe.

A 2019 study found that up to a third of gym surfaces have the potential to become an intermediary for infection.

Refer to Nytimes