Strengthen the immune system against colds

When it gets cold, the cold virus attack begins. This is how the attacks can be fended off successfully

Fit in wind and weather: The immune system makes an important contribution to this

© Shutterstock, Inc. / Olena Yakobchuk

When the breath forms white clouds in the morning air, one thing is clear: winter is coming. And with it often the first cold. Pathogens float from person to person in tiny drops, lurking on the next door handle.

Respiratory infections spread rapidly, especially in the cold season. Although they are mostly harmless, they are always annoying. It is understandable that many want to arm themselves by strengthening their defenses.

Killer and phagocytes: protection against disease

The survival of our organism depends on the immune system, in summer and winter. Without our noticing it, we are constantly surrounded by pathogens, bacteria, viruses, fungi. But they must first overcome the sophisticated system of our defense.

Immediately after penetrating the body, they hit the foremost, innate front for all of us: killer cells recognize which body cells are already infected and destroy them. Phagocytes attack the intruders and digest them.

At the same time, they activate the second line of defense, the so-called specific immune system. It produces tailor-made substances that attach to the pathogen and make it immobile. They also mark it so that the defense can recognize it more easily. The better the interaction of the immune cells, the less chance there is of an infection.

The immune system is difficult to see through

But how do you know whether your own defense is fit or weak? We know that some diseases and some medicines increase the risk of infection. People who have poorly controlled diabetes or who have to take cortisone for a longer period are at greater risk.

In a fundamentally healthy person, however, it is far more difficult to make a statement about the state of the defense. While a heart expert has a few tests on hand to assess the condition of the organ, this has not yet been possible with the immune system.

"Only severe immune defects can be recognized. These are rare, however," explains Professor Thomas Kamradt, head of the Institute for Immunology at Jena University Hospital.

Frequent infections? Can be just bad luck

If the immune system is damaged by a disease such as advanced HIV infection or insufficiently developed due to a genetic disorder, this can also be seen in the blood. It is different with a basically healthy immune system: "It is not so easy to test whether the immune system is in top shape or if it is working properly," says Kamradt.

Even the number of infections is not a sure indicator of weakness or strength, unless these are particularly severe. "More than three febrile infections are considered suspicious, each of which lasts for at least four weeks."

Maybe you were just unlucky and got coughed up by someone with a cold in the S-Bahn. Or had contact with unwashed hands. Pathogens stick to the handrail in the bus and the banister leading to the office. Frequent hand washing is considered one of the most effective ways to prevent infection.

First hurdle for pathogens in the nose

© W & B / Veronika Graf


© W & B / Veronika Graf

The cilia move back and forth quickly and thus carry viruses and bacteria out of the nose. Immune cells drift through the body in the blood and migrate from the vessels into the tissue.

© W & B / Veronika Graf

When you have a cold, the goblet cells build up more mucus in order to transport the pathogens out of the body.


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In order to make us sick, cold viruses have to penetrate the body's first barrier: the mucous membrane, for example in the nose. This is equipped with various defense mechanisms

Mostly a stable equilibrium

A hallmark of a healthy immune system is not just its clout. If it becomes active when it shouldn't, it can be dangerous. This is the case, for example, with autoimmune diseases in which the immune system attacks structures in the body. Even in allergy sufferers, the immune system is misdirected and attacks harmless intruders. "It's about the right balance," explains medic Kamradt.

Fortunately, our body's defenses are not that easily unbalanced. "The immune system is quite robust," says Kamradt. You can also give them important support so that they can do their job in the best possible way.

"You sleepyhead!" For Dr. Tanja Lange is not insulted by this. A good night's sleep, the researcher from the Clinic for Rheumatology and Clinical Immunology at the University Hospital Schleswig-Holstein is convinced, means a still underestimated source of health and well-being. It is well known that good sleepers are better at warding off infections. Even a single night of wakefulness makes us more vulnerable.

The defense never sleeps

But what happens to our defenses when we are asleep? In a study by Lange's team, participants were allowed to sleep on one trial night while they lay quietly but awake in bed on another.

Differences could actually be seen in the blood: If immune cells encountered components of bacteria, they reacted more strongly after a restful night. Other immune cells were found in fewer numbers after sleep.

"We suspect that they migrated to their main workplaces in the lymph nodes or in the spleen," says Lange. Overall, scientists assume that a kind of "reset" of the immune system takes place during sleep: it shuts down its activity and goes back to its basic setting. If pathogens have penetrated, it can then fight them with full energy.

Stress inhibits the immune system

You should therefore sleep well even after a vaccination. Test persons who stayed awake the night after developed a weaker protection. "A difference was measurable even after a year," says Lange.

The cause of these effects are, among other things, changes in the endocrine system. During sleep, for example, the level of the stress hormone cortisol, which inhibits the immune system, drops. In addition, more immune-stimulating growth hormone is released.

Food for the immune system

You are what you eat. Recent research has shown this ancient wisdom in a new light. Our menu determines, among other things, who feels comfortable in our intestines. Billions of microorganisms live there - an ecosystem of their own.

It has long been known that the germs help break down food. New research also shows that this so-called microbiome interacts with the organism in a variety of ways.

Even with our defense. "Without the germs that live in us, no functioning immune system can develop," explains immunologist Kamradt. They represent a kind of training camp that keeps the immune system fit and in balance.

It should be varied

Substances that the human body cannot produce itself, such as short-chain fatty acids, also very likely play a role. Intestinal bacteria produce these from our food and thus influence the immune system.

The intestinal flora differs from person to person. Not every type of ecosystem seems cheap. But we still don't know enough about it to be able to give specific nutritional tips. In any case, a varied diet with little sugar, little meat and little animal fat, but lots of fiber, plant fibers, minerals and vitamins is advisable.

For example, vitamin D, which the body produces with the help of the sun, is important for the immune system. Especially in winter the level in the blood goes down. Many experts therefore recommend taking vitamin supplements. The pharmacy can also advise on this.

Fit by doing without

If you want to avoid infections, you should avoid toxins that weaken the immune system. "Alcohol and cigarettes in particular play an important role," says immunologist Kamradt.

Smoking damages the mucous membranes in the airways. The cilia that catch pathogens and transport them out of the body are also paralyzed and destroyed in the long term. Therefore, those who smoke suffer more often from respiratory infections and pneumonia.

Those who drink over thirst must also expect more infections. Studies have shown that alcohol paralyzes important cells of our immune system.

As researchers from the Loyola University Health System in Chicago (USA) were able to show, the activity of the immune system increases at the height of an intoxication - only to decrease drastically a few hours later. A few glasses too many, the experts conclude, make us more susceptible to infections.

Vaccination trains the immune system

A quick pikse - and we are protected. "Vaccinations are good training for our defense," explains Kamradt. You bring them into contact with viruses and bacteria without making you sick.

For this purpose, weakened pathogens or dead parts of them are injected. The latter is also the case with the flu vaccination. Because the viruses are constantly changing, a new vaccine comes out every year.

The immune system recognizes the vaccinated substances as foreign. The defense receives the signal to produce antibodies: tailor-made defense substances against the pathogen. This knowledge is not lost.

"Our defense has a kind of memory," says Kamradt. If the pathogen penetrates again, we do not fall ill. The training made us immune. So far, however, there is no vaccination protection against cold viruses.

Hard by hardening?

Sauna, cold showers or ice baths: Many swear by the fact that hardening protects them against cold viruses. What is certain is that the alternation of heat and cold improves blood circulation. For the muscles that widen and constrict our vessels, the stimuli are like exercises in the gym.

The blood is, so to speak, the highway for our body defenses. Due to the hardening effect, immune cells get better to the places where the pathogens penetrate, for example in the mucous membranes. At least that's the theory.

Saunas and alternating showers have a positive effect

So far, this effect has hardly been proven in studies. "There is no good evidence that hardening has an effect on the immune system," says Professor Karsten Krüger, sports immunologist at the University Clinic in Hanover.

A small study by the Competence Center for Naturopathy at Jena University Hospital was able to determine an effect on chronic obstructive bronchitis (COPD). The test subjects received cold washes and washes for ten weeks. After that, the number of important immune cells in her blood had increased by 13 percent. In addition, the number of infections fell. Experts agree on one thing: if you like going to the sauna or start the day with alternating showers, you are doing yourself something good.

Run away from the infections

Hardly anything gets our immune system up to speed as effectively as exercise. Research has shown that people who exercise regularly have fewer infections. Tests have shown that more activity in life improves resilience.

Those who pulled themselves up from the sofa and started walking, for example, were less sick afterwards. "It is important not to overload yourself, but also not to take too long breaks," says Krüger.

An effect can even be demonstrated in the blood. "We examined the number and activity of individual immune cells," reports Krüger. And indeed: when test subjects are physically active, the ability of natural killer cells to recognize and attack pathogens improves, for example. They also divide faster and produce more signal substances to get other immune cells going.

Sporty fountain of youth

In addition, exercise keeps you young - including the immune system. Like all organs, the human defense also ages. "If a 60-year-old catches the same virus as a 30-year-old, the older person is more likely to get sick," says Krüger.

Fewer functional immune cells circulate in his blood. In addition, the defense can no longer differentiate so well between foreign and endogenous - the risk of some autoimmune diseases such as rheumatism increases.

In addition, there is an unfavorable permanent activation, which leads to a basic inflammation in the body. "All of these changes can be turned back a little," says Krüger. So an anti-aging effect.

Relax sometimes

But how does exercise affect the immune system? "The muscle can be compared to a hormonal gland," explains Krüger. When it is active, so-called myokines, i.e. muscle messengers, enter the blood.

Many of them affect the defense. Hormones such as adrenaline and noradrenaline, which are increasingly released during acute stress, also have a stimulating effect.

As with any active ingredient, the dose has to be right for exercise. Those who put too much strain on themselves are more susceptible to infections. The defense needs a few days to recover after a marathon.

"Regeneration is important for a positive effect," says Krüger. According to the immune expert, which type of exercise you choose does not play a decisive role. "The main thing is to do them regularly."

This is how your local pharmacy can help

  • Well protected? Vaccinations are also important for adults. Some pharmacies offer advice on this. Ask for!
  • Have you already caught a cold? If you take zinc tablets (daily dose at least 75 milligrams) at the first symptoms, you can shorten the period of suffering a little.
  • Undersupplied? Experts assume that many people in our part of the world have too little vitamin D in their blood in winter. Diet supplements can help.