How Does The Flu Affect The Body?

Thanks to scientific studies, we have made progress in understanding the effects of influenza on the body. Most of us have suffered from this disease at some time and know that it is not pleasant. In this article, we’ll find out where the flu symptoms come from.

Influenza is a viral illness, mainly seasonal. Many of us have had it at some point and know from experience how the flu affects the body. However, there are mechanisms that are activated in the face of infection and that cause symptoms.

Typically, the signs of the flu are fever, headache, muscle aches, and fatigue. When it evolves normally without complications, all are resolved without leaving any sequelae.

But some cases of the flu are more serious. When the virus becomes fixed in organisms weakened by immunosuppression, by extreme ages or by the presence of another basic pathology, evolution to death is possible.

We also need to be clear that when we talk about the flu it is not the same as the common cold. Colds are much milder and the consequences are minor and superficial. The way the flu affects the body is different because the aggression is greater.

The influenza virus also has social effects. Four in ten people with the flu miss work during their illness, and almost all are confined to reduced sports and social activities.

Among the symptoms perceived by individuals, according to various surveys, the most annoying is the feeling of fatigue. Almost half of people with the flu report that the lethargic period is intense. Although fatigue is the most notorious and annoying, we will see that it is caused by fever and muscle pain. Behind it is the inflammation of the tissues.

The microscopic process of influenza

The outwardly manifested signs and symptoms of the disease are expressions of how the flu affects the body at a microscopic level. Various cellular mechanisms explain why we have fever, headaches and myalgia.

Once the influenza virus enters the body, it has about eight hours to replicate before it is detected by the human immune system. Its gateway is the airway, and it relies on the epithelial cells of the lung.

By entering human cells, the virus takes hold of the organelles of cells that produce proteins. He then puts these organelles at his service. In short, it takes advantage of what the host already has to multiply and survive. The new viral copies then search for other cells to infect.

When the human immune system is activated to fight the influenza virus, several reactions are triggered. These reactions establish the known symptoms of the flu and explain how the flu affects the body.

The first thing to activate for defense is white blood cells. These cells will be the first line for the subsequent activation of substances that mediate inflammation: cytokines.

Cytokines can be understood as small hormones that carry a message in the immune system. Their mission is to cause the activation of organs and tissues to eliminate the virus from the body as quickly as possible.

How the flu affects the body: fever

When we talk about the effects of the flu on the body, inevitably we have to refer to fever. The pathology is accompanied by fever, and this is one of its characteristic signs.

Fever occurs when the hypothalamus gives the command to raise the body temperature. This order is given because the hypothalamus senses the presence of substances that we call pyrogens. Among the pyrogenic substances we have the components of bacteria and viruses and cytokines.

By increasing the body temperature, our white blood cells become more efficient. In reality, fever is a defense mechanism, rather than a pathological consequence. In addition, at high temperatures, microorganisms have a harder time reproducing.

Headaches

It is not entirely clear how the flu affects the body to produce headaches . It is understood that when there is a fever, a headache makes sense. But that’s not just what happens with flu syndrome.

Cytokines have also been associated with headaches. One in particular, called interleukin-1, is an inflammatory cytokine, just like interferon.

Both cytokines and high temperature cause vasodilation. The vessels in the body widen and this blood flow can explain the headache by an intrinsic mechanism similar to that which explains migraines.

How the flu affects the body: muscle pain

Finally, myalgia is also a hallmark of the flu. Scientific studies have found a genetic explanation for this muscle pain due to the flu and there is, of course, the action of cytokines.

During infection, our body increases the expression of certain genes which are promoters of myocyte destruction. Myocytes are the cells of muscle tissue.

At the same time, inflammatory cytokines cause muscles to ignite in order to fight off the virus. Inflammation of the muscles is painful and depletes them, because cellular resources are stubbornly strained in the fight against the virus. This is where the great fatigue that people with the flu report is.

In conclusion

We know a lot about the mechanisms that explain how influenza affects the body, but there is still a lot to study. The truth is, when we are infected we experience fever, headaches, and muscle pain.

Symptoms are expressions of the fact that our immune system is fighting the virus. At the same time, we must do our part to speed up the process, with adequate rest and timely medical consultation.