November 3, 2025, 3:03 am | Read time: 5 minutes
Many people ignore the first signs of a cold—after all, coughs, runny noses, or sore throats usually disappear on their own. But those who don’t take a break despite being sick risk serious secondary illnesses. What happens in the body during a cold, why rest is so important—and when it’s better to seek medical advice.
Warning Signs: When a Cold Is No Longer Harmless
In uncomplicated cases, health usually improves within a week. However, if the illness lasts longer or individual symptoms worsen, it may indicate a lingering infection.
“Typical warning signs are persistent physical weakness or fever that hasn’t subsided after four days,” says Jakob Maske. A recurrence of symptoms should also be a cause for concern.
A pressing sensation in the forehead, cheeks, or upper jaw can indicate sinusitis. “This usually becomes significantly stronger when bending over,” explains Torben Ostendorf. If the cough worsens, sputum appears, and fever rises, bronchitis may be present. “Many affected individuals also suffer from fever,” Ostendorf adds.
If additional symptoms such as chest pain, shortness of breath, or persistent fatigue occur, there is a suspicion of myocarditis. Heart palpitations or dizziness can also occur in this context—a rare but serious consequence of a lingering infection.
When to See a Doctor?
“Whenever the mentioned warning signs occur or if you notice unusual symptoms for yourself, you should seek medical help,” recommends Jakob Maske.
Fever over 39 degrees should also be medically clarified to determine if it’s an uncomplicated course. “This is especially true for patients at risk with chronic illnesses,” emphasizes Ostendorf. This includes people with lung diseases such as COPD or cardiovascular problems.
How a Cold Develops—and What Happens in the Body
A cold is almost always triggered by viruses that settle in the upper respiratory tract. The most common pathogens come from families such as rhino-, adeno-, or coronaviruses. Transmission usually occurs through droplet infection—when coughing, sneezing, or speaking—or via contaminated hands and surfaces.1
“It is usually an inflammation of the upper respiratory tract, such as the mucous membranes in the nose, throat, and bronchi,” explains Torben Ostendorf.
The body’s defense reacts by activating various protective mechanisms. “Here, the body responds with various defense mechanisms that can manifest in different symptoms,” says Jakob Maske. The formation of antibodies and memory cells plays a central role, allowing for a faster response upon later contact with the same viruses.
Infections That Frequently Affect Children
Watch Out for These COVID-19 Symptoms Now
Why Stress Increases the Risk
Those who don’t pause during an infection put additional stress on the body, which significantly hinders the healing process. “During a cold, it’s important not to further burden the body,” warns Ostendorf. Sports and other physical exertions should therefore be consistently avoided. “Otherwise, there’s a risk that the immune system can’t focus on fighting the inflammation,” explains the family doctor.
If this phase is not taken seriously, the infection can spread to other organs. “The consequences can be that a runny nose turns into sinusitis or a cough becomes bronchitis or even pneumonia,” Ostendorf says. Particularly critical: a possible myocarditis. “At that point, it’s no laughing matter,” he says.
Allowed or Forbidden? What to Consider During a Cold
If you feel well during recovery, you can cautiously move in the fresh air—without overexerting yourself. “Light physical activities are allowed, but of course, no sports during an infection,” says Jakob Maske. “Competitive sports should also not be performed at full intensity for up to two weeks after an infection.” This time frame serves for complete recovery.
Even in everyday life, it’s better to take breaks than to push through. “You should allow yourself as much rest as possible,” advises Torben Ostendorf. Physical recovery is a top priority—as is avoiding work-related or personal stress.
Course and Duration–What Is Normal
A cold often begins with a mild sore throat or a scratchy throat. Within a few days, a runny nose and cough follow. Often, one feels fatigued, and sometimes headaches or body aches occur. Generally, symptoms subside after one to two weeks. Sore throats and stuffy noses usually pass quickly, but a dry cough can persist longer—on average, up to 18 days, occasionally even three weeks.2
Antibiotics are not suitable for simple viral infections, as they only work against bacteria. Pain relievers or fever-reducing medications can alleviate symptoms but do not change the course of the illness.
Colds Are Common–But Rarely Dangerous If Taken Seriously
On average, adults catch a cold two to four times a year. Children bring infections home from school or daycare much more frequently—up to twelve times a year is not uncommon. The risk of infection increases, especially in the fall and winter.
Even if the course is mild in most cases, infections should not be underestimated. With sufficient rest, healthy caution, and a bit of patience, the risk of complications can be significantly reduced—and the path to full recovery is safer.
*with material from dpa