Infection risk gym

Aerosol-borne virus transmission during exercise


“Breathing under physical exertion releases more aerosols – and thus potential virus particles” – warn sports physicians.
Fitness studio operators have long since accepted their responsibility and use ventilation systems to “vent” aerosols.

In the cooler months, however, it becomes more and more difficult to ventilate – because it is hardly possible to ensure that the incoming fresh air is heated up quickly.
That is why indoor air experts recommend the installation of air purification devices.

Sport favors aerosol emissions

Woman breathes
People run through the forest in winter

Physicist Bert Blocken from the University of Eindhoven published a study in which he showed that a cloud of the finest bioaerosols can spread up to 10 meters behind a runner . A minimum distance of 2 meters is not enough here. When cycling (Velo-Sport) the recommended minimum distance is even 20 meters .

Perikles Simon, a renowned sports scientist at the University of Johannes Guttenberg University in Mainz, also points out that humidity is a decisive factor in the transmission of viruses through the air. “[…] depending on the weather , a virus like smoke spreads in the air,” explains the doctor and advises athletes to use sunny weather instead of planning the daily lap in fog and haze. 

The background behind this professional advice: Enveloped viruses, and thus also influenza and Sars-CoV-2 viruses, like it humid: If the humidity rises above the critical value of 60 percent , viruses have an easy time of it. But what does all of this have to do with exercise in the gym ?

Fitness studios ensure healthy air

If sport – like in the fitness studio – is done in closed rooms, the aerosol load in the room air increases by leaps and bounds. People exercising on the machines can do sports on the spot in the studios. If the court or the exercise equipment now re-occupied, the following athletes breathe in the worst case in the very same aerosol cloud that his predecessor in front of him left has. 

Disinfecting and cleaning the devices and grip points is also not a sufficient measure to master the risk of infection via bioaerosols. Studies show: Without measures, the finest droplets can be detected in the room air for up to 5 hours .

Regular ventilation plans should further minimize the risk in the warm summer months. In autumn and winter, however, experience has shown that the windows remain closed for most of the day: 

Many operators of sports facilities react preventively in order to give sports-loving customers a feeling of security during training and to prevent infections based on the latest findings.

Air hygiene in sport is the be-all and end-all

Areas and industries in which many people are in confined spaces in closed rooms are concerned about air hygiene and take measures to prevent the spread of viruses or to keep them as low as possible. Airlines show in an unprecedented way that high-quality air hygiene is also possible in closed rooms in which many people are staying at the same time : 

Advanced ventilation technology ensures that all of the cabin air in the aircraft can be completely exchanged in just three minutes. In addition, HEPA filters are used to filter out virus particles from the portion of the filtered air. 

What is possible above the clouds also works on the ground:
Air purification systems with ION HEPA filters ensure that the ambient air is free of germs and viruses. Virus transmission is  inhibited , while viral genetic material is rendered harmless in an active, destructive process  .

Suitable air purifier models for fitness studios: 
high-frequency systems and air purifiers from the GRAN 900 model series .


FAQ: humidifiers

Does a humidifier make sense? Which humidification methods are suitable for your own individual needs and requirements and what can a humidifier actually do? These questions are probably at the top of the list for all those who deal with the topic of air humidification. Reason enough to take a closer look at the most frequently asked important questions …

Does a humidifier make sense?

Woman at the PC with glasses hand

Many of those affected are familiar with the problem in the cold months of the year, when there is strong heating: if the room air is too dry, it irritates the eyes and respiratory tract and can even lead to chronic headaches.

The solution is a humidifier that keeps the relative humidity in the room at a constant optimum . If you are thinking about buying a humidifier, you should consider a few points and be aware of the fact that air humidification does not automatically mean air purification.

If the air humidity is also in an optimal reference range, which counteracts the above-mentioned complaints and symptoms, other dangers come to the fore at the same time , which threaten as potential risks in the event of improper use and insufficiently hygienic cleaning.

Air humidification: yes, but correctly and with a sense of proportion

For people who suffer from irritated mucous membranes or who even complain of headaches due to insufficient humidity, a professional air humidifier is an acquisition that is worthwhile and counteracts the symptoms quickly and effectively .

However, if the humidity is too high, mold growth can result. Therefore, it is important to have the right setting for a comfortable and healthy feel-good climate with optimal humidity. The relative humidity in living spaces should be between 40 and 60 percent , but never below 35 percent and above 65 percent. 

With a hygrometer, the humidity in rooms can be measured reliably with just one movement. A preliminary test helps you decide whether you should consider purchasing a humidification system.

Analog hygrometer and thermometer

In some rooms, the use of an air humidification system can be particularly recommended: This applies, for example, to rooms in buildings where the fabric of the building consists to a large extent of building materials with high sorption properties . Some building materials such as chipboard, wood or plaster of paris absorb the air humidity to a greater extent than conventional masonry.

What is a humidifier good for?

A humidifier regulates the relative humidity in closed living and working spaces. In this way, an air humidification system can help to alleviate or prevent typical symptoms and complaints that are directly attributable to excessively dry air .

A correct and needs-based setting of the humidifier is important: If the humidity is too high, not only mold has an easy time. The risk of germs, viruses and bacteria being transmitted also increases.

Which humidifiers are the best?

Humidifiers come in all shapes and colors. This is due to the fact that the various humidification processes are based on different technologies . A distinction is made between passive and active air humidification: All processes aim to regulate the air humidity, whereby there is no risk of overhumidification with passive humidification processes.

Before deciding on one of the technologies mentioned above, personal needs and requirements should be weighed and taken into account. The decision can be influenced by the following aspects:

  • Volume of the device
  • Energy costs
  • Hygiene and maintenance needs
  • Water hardness
  • Risk of potential overhumidification of the room air

Where should a humidifier be located?

There are many potential places where a humidifier can be found in everyday life. However, there is one important aspect that you should keep in mind when choosing the right location for an air washer : to avoid mold formation, a distance of at least 10 to 30 centimeters should be maintained (depending on the model) to furniture standing around .

Placing the air washer directly in front of cupboards or walls is also not recommended: the moisture threatens to condense on the directly adjacent surfaces. The risk of mold growth is increased.

A location that is as free as possible in the room not only reduces the risk of mold formation, but also guarantees that the air enriched with moisture is optimally distributed in the room.


Damp basement – what to do? Cellar drying solutions

If the basement is damp, this also means moisture for the things that are stored there and, with certain moisture values, also a health hazard for you as a resident. We explain how moisture is created and what you can do about it.

basement damp

Many cellars are damp and therefore have a very limited usability. With certain humidity values ​​there are also health risks for you as a resident . But how do you find out if your basement is too damp?

First there is the gut feeling. If you have the impression that the basement is damp, then your basement is damp too. You can check it with a good hygrometer *, which shows you the humidity in percent exactly. 

All values ​​above 70% humidity are a major health risk, as mold can then form. 

If you don’t have a hygrometer in the house, put a piece of paper, wrapping paper or cardboard in the room that appears damp to you. 

If the paper appears damp or even wavy after a day or two, this is an indication of moisture and it is time to find a solution!

Cellar drying against mold

Now it’s time to act and dry the cellar . Ventilation is not fundamentally wrong, because an exchange of air prevents mold. 

But: Whenever you ventilate and it is only three degrees warmer outside than in the basement, the outside air condenses as it flows in and forms even more moisture. 

Even if it is very wet outside, i.e. there is already a high level of humidity outside, you do not want to let this moisture into your basement. 

So what to do

Combat seasonal humidity with a dehumidifier

If it’s a seasonal problem, an excellent solution to moisture is a dehumidifier. 

You can set it so that it switches itself off again at a certain level of humidity. The dehumidifier keeps the humidity at the desired level. 

If you also hang up and dry your damp laundry in the basement, an excellent side effect of the dehumidifier is that your laundry dries faster and the moisture is collected. 

The dehumidifier acts here as a clothes dryer.

Do you have any further questions, comments or a story about your cellar?


How useful is air disinfection?

A lot of money for nothing – or is air disinfection an effective weapon in the fight against Covid-19 / Corona and flu viruses?

The fact that the new Sars-CoV-2 virus is transmitted via ultra-fine droplets, so-called aerosols, is considered to be certain. Air disinfection is currently being discussed in order to keep the risk of infections as low as possible. Companies and service providers specialize in a new type of air purification, which is viewed in a critical light by experts.

warning sign

With air disinfection against Covid-19?

Active ingredients for air disinfection split the shell of the enveloped corona virus and render it harmless. If it is up to the manufacturers and distributors, the more or less environmentally friendly means should make an important contribution to combating the pandemic. However, medical professionals and health professionals are concerned.

Air disinfection through chemical aerosol nebulization?

Air disinfection in the restaurant

The Robert Koch Institute considers air disinfection to be “not very effective and, for reasons of occupational health and safety, questionable, as disinfectants can be inhaled.” The BfR is also unequivocal and advises against the use of disinfectants for air disinfection in private households.

Room-air disinfection using vaporized disinfectants may at least be viewed critically, but the question remains whether spray disinfection is not a suitable, holistic process for cleaning and disinfecting surfaces?

The German Advisory Center for Hygiene also firmly rejects this approach: Not only the fact that aerosols enriched with disinfectants remain in the air for a long time – the fine mist only partially and unevenly wets the surfaces to be disinfected.  Mainly formaldehydes and hydrogen peroxides are used, which – if they are exposed to the human organism – are ascribed to have a harmful or carcinogenic effect. A disinfectant that is constantly released into the room air and can be inhaled without hesitation has not yet been invented

Pitfalls of indoor air disinfection

Effective air disinfection is more difficult to implement than it appears at first glance. The duration of application of the measures for indoor air disinfection is usually longer than that for the decontamination of surfaces. Apart from the increased risks that spray disinfection poses for the human organism when inhaling aerosols, upholstery and furniture present a further difficulty: Many surfaces absorb the disinfectants, which makes it impossible for the germicidal antiseptics to completely penetrate the room air. Any air currents also complicate the sustainable and effective real-time disinfection of the room air.

Gentle air cleaning and healthy air humidity as an alternative to aggressive disinfectants

Air purifiers and air humidification systems are currently in high demand. Modern room air conditioning technology has brought technical innovations onto the market that, in times of corona and influenza viruses, represent an equivalent and sustainable alternative to aggressive air disinfection: The cleaning of the air using highly effective ION HEPA filter devices and direct evaporators. Extremely effective – and without any health risk.