Sport with a cold: continue exercising or take a break?

A cold and sport - do they go together?

When we're in top form and training is going really well, it's difficult for many of us to take a break from running or road bike training. But when we catch a cold in winter, this is often exactly what we need. Our body needs rest, recuperation and time to recover.

But not all colds are the same and sometimes exercise in the fresh air can even help you recover. What your body needs now depends on the type and severity of your symptoms.[1]

Colds with mild local symptoms

In winter, most of us get a runny nose more quickly than in summer. The dry heating air and the change in temperature between indoors and outdoors put a strain on our immune system and mucous membranes. If you only have isolated local symptoms such as a slight cold, but otherwise feel fit, there's nothing wrong with moderate exercise.[2]

So you can go for a walk, Nordic walking or relaxed jogging or cycling, but you should make sure that your training is gentle and involves little physical exertion.[3] The intensity and volume of training should be significantly reduced compared to regular training and you should skip speed runs and interval training until you are 100% fit again.[4]

Cold with systemic symptoms

However, if you notice that you have several different symptoms and feel weak and exhausted , you should take a break from training and refrain from even moderate exercise.[5] The following symptoms often occur together with a flu-like infection:

• Cough

• scratchy throat

• a cold

• headache

• aching limbs

You should definitely avoid exercise if you have a sore throat or a cough.[6] This is especially true if the symptoms occur together and are perhaps accompanied by aching limbs and a fever. However, exercising when you have a cold without a fever is also not a good idea as soon as several symptoms occur. You should also stop exercising as soon as you notice increased heart palpitations with a cold.

Exercising despite the flu or Covid-19?

With a flu-like infection, the symptoms often come on gradually and slowly and are mild. However, if you are incapacitated from one day to the next with a fever, aching limbs, chills or other symptoms, you may have caught the flu.[7]

In this case, bed rest and a complete ban on exercise apply. Your body is busy fighting the pathogens and regenerating. Exercise would overtax and overload your body and could significantly delay the recovery process and have health consequences. The same also applies to endurance sports after corona.[8]

Why does sport harm the recovery process?

But why is it actually bad to exercise when you have a fever, aching limbs and other cold symptoms? Although exercise is good for the immune system when you are healthy, this is unfortunately not the case when you are ill. Your body now uses a large part of your energy to fight off pathogens and regenerate your damaged cells.

When you exert yourself physically, you put your body under additional stress and use valuable energy that it actually needs for the defence and recovery process. As a result, your immune system works more slowly and less effectively. You take longer to recover and 'drag out' the cold.[9]

Unfortunately, the myth of 'sweating out a cold' is not true either. The warmth of the bed promotes blood flow to the mucous membranes and leads to an increase in the release of antibodies. Too much heat, such as when exercising or taking a sauna, puts a strain on the body.[10]

Sport with a cold: possible consequences

We often find it difficult to overcome our inner ambition and really take a break from training. You may also be afraid of missing out and losing the hard-earned training progress. But if you don't recover sufficiently and drag out a cold, your training will ultimately suffer even more and, above all, for longer.[11]

But it's not just your training routine that can suffer from a protracted flu or flu-like infection. If you don't recover sufficiently and push yourself too hard physically, this can result in long-term health problems.

The pathogens can then spread further and an infection of the upper respiratory tract organs can spread to the bronchi, sinuses or even the lungs.[12] In the worst case, the cold can even lead to myocarditis.[13] You can recognise this serious complication by the following symptoms:

• Shortness of breath

• Tightness in the chest

• palpitations

• dizziness

• Fainting

• Water retention in the legs [14]

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When to start exercising again?

In order to avoid these health problems and to be fit again as quickly as possible, it is better to recover from a cold or flu, get plenty of sleep and drink warm tea. Once you are fit again, you can slowly return to your daily training routine.

But when can you actually start exercising again? The answer to this question also depends on how seriously ill you were. If you have a mild cold, you should wait until you have been symptom-free for at least two days.[15]

If you had a high fever of 38°C (100°F) or above, a real flu or Covid-19, then you should stop training for at least two weeks in total.[16] It is best to wait until you have returned to your normal resting heart rate before training.[17]

You can then slowly start training again. Pay particular attention to your body and its needs during this phase. If you return to training too quickly and too intensively, you will soon be back in bed with a fever. It's best to start with brisk walks, then move on to slow basic units and finally increase the intensity of your training step by step.

Preventing colds with sport

If you already have a cold, unfortunately the only thing that will help you to recover properly is bed rest and a good amount of sleep. Exercise is out of place during this time, delays the recovery process and, in the worst case, causes health complications.

However, if you are fit and healthy and want to toughen up for the winter and strengthen your immune system, endurance training such as cycling or jogging is just the thing for you.

Not only does exercise and sport strengthen the immune system, but the fresh air is also good for us. The humid air outside offers a healthy change from the dry heating air, as it strengthens our mucous membranes. This makes it harder for viruses and other pathogens to penetrate our respiratory organs.[18]

So don't shy away from the cold winter air, get out of the house and start exercising.