How Does Playing Outside Boost Your Child’s Immune System

Kid playing with water hose
February 2nd, 2021 0 Comments

Do your ever get the sense that kids are becoming less resilient than previous generations? And just to be clear, I am not strictly talking from a mental perspective here.

Over the last few years, you may have begun to notice that children are becoming less physically robust. Within this, they not only appear to be moving less, but they also seem to be getting sick more often.

Well, there could be a reason for it – and it relates to outside play.

What is a strong immune system?

Sand toys


Your immune system is a complex piece of machinery.

It is collectively made up if a variety of organs, cells, and chemicals, that help fight against invading pathogens. Some of the most well-known components of your immune system include white blood cells, antibodies, your lymphatic system, spleen, thymus, and your bone marrow.

Within this, there is also a growing body evidence suggesting that the trillions of bacteria living in your gut – also known as your “microbiome” – are also an integral part of your immune system [1].

These little guys ultimately act as your first line of defense against the outside world. As such, they help to fight and destroy any harmful bacterial, fungi, and viruses, that enter your digestive tract from the external environment.

Taking all of this into consideration, a strong immune system is comprised of a healthy microbiome, in conjunction with well-functional immune organs and cells.

Now, many people believe that they are helping boost the function their children’s immune system be keeping them clean – but if what if I told you it might be doing more harm than good?

The problem with too excessive hygiene

When you are a child, you get exposed to various germs.

Putting it simply, this exposure allows your immune system to develop the ability to fight of these same (and similar) germs in the future, making it stronger and more effective.

However, over the last few decades we have seen an increase in hygiene standards across the globe – which has given rise to the “hygiene hypothesis” [2].

This unique hypothesis suggests that because hygiene products have become more effective and more readily available, home environments have become cleaner and cleaner. As a result, kids are no longer exposed to the level of germs as previous generations, and their immune systems are becoming compromised.

Importantly, this effect seems to be compounded even further when we consider that children are also playing outside less – meaning that their exposure to germs outside the home is also being impacted.

But is the hygiene hypothesis true?

While it would be unethical to conduce a randomized controlled trail on the topic, over the last few decades the incidence of asthma, allergies, and flu have increased significantly in developed countries like the USA [3],

This does provide some sound evidence indicating that it might not be far from the truth.  

The dirt connection

Kids running on a trail in the woods

The main reason behind this finding appears to com back to your child’s microbiome.

When your children play outside, or are exposed to germs, they are exposed to bacteria. These bacteria enter the digestive tract, adding to their microbiome. This can lead to an increase in microbiome variability (i.e., the number of different bacterial species within the gut), while also increasing its size.

All of which strengthens that first line of defense, making your immune system much more robust as a result.

But when they do not get this exposure, their microbiome becomes less efficient. This leads to more pathogens enter the body (rather than being destroyed in the gut), which can overload the immune system and result in illness [4].

So, the take home message here?

Get your kids outside and in the dirt to build a robust, resilient, and well-functioning immune system.

How much outside play time is enough?

Now you might be wondering if there is certain amount of time children need to be outside for these benefits to occur – and to date, we do not have any research answering this question.

However, we can look to physical activity guidelines for encouragement.

Most health organizations around the globe recommend children get at least 60 minutes of moderate to high intensity exercise in per day. This should also include 2-3 days per week of high-impact exercises, like sport, rough play, or even resistance training.

Taking these on board, it would be worth trying to get half your child’s physical activity outside to ensure a decent amount of exposure.

I would also encourage you to pursue outdoor play in a variety of different locations throughout the year. This will ensure exposure to different types of pathogens, which will further contribute to the development of a robust immune system.

Related Article: Kids Need To Move To Improve

Tips for getting outside during the pandemic.

kids balancing on a wooden fence in a yard 

Now I certainly appreciate that getting out and about for outdoor play in the middle of a worldwide pandemic can be easier said than done – which is why I wanted to finish with some tips that can help you get outside during COVID-19:

  • Scope out the local area: my first suggestion would be that you jump on google maps and look for any parks in the area. These offer the perfect place for you and your kids to get in some dirt play outdoors in a brand new location, without having to travel around.
  • Make walking more exciting: when I go on afternoon walks with my kids, I try and set challenges that result in them getting their hands dirty. This could be something as simple as practicing hand stands or cartwheels every time we get to a patch of grass, or even trying to climb every third tree we come across.
  • Use your own backyard: if you are hesitant to get out to any local areas, look to your backyard for inspiration. Set aside a specific area where your kids can dig, build, and just have fun. This is a great way for them to get their hands dirty and use their imagination too.
  • Still social distance: if you do go out to a crowded park and there are people around, try and keep your space. Remember, we want the germs from the ground, and NOT germs from other people’s lungs.
  • Take up some new hobbies: and lastly, taking up some hobbies like fishing or hiking is a great way to get your kids exposed to a variety of different environments and avoid people in the process. This is great for microbiome diversity and can help them build a host of new skills.

And there you have it – five great tips to take you outdoor play to the next level during COVID-19.

Take Home Message

It might come as a shock, but excessive hygiene practices that have seeped into modern society might be making your kids sicker.

Which is where outdoor play enters the equation.

By exposing your kids to germs found in the environment, outdoor play can boost the robustness of their microbiome, making their immune system more effective. This can reduce risk of illness, making them healthier and happier in the process.

So, what are you waiting for – get outside and get dirty.


  1. Belkaid, Yasmine, and Timothy W. Hand. “Role of the microbiota in immunity and inflammation.” Cell 157.1 (2014): 121-141.
  2. Bloomfield, S. F., et al. “Too clean, or not too clean: the hygiene hypothesis and home hygiene.” Clinical & Experimental Allergy 36.4 (2006): 402-425.
  3. Liu, Andrew H. “Revisiting the hygiene hypothesis for allergy and asthma.” Journal of Allergy and Clinical Immunology 136.4 (2015): 860-865.
  4. Leung, Marcus HY, and Patrick KH Lee. “The roles of the outdoors and occupants in contributing to a potential pan-microbiome of the built environment: a review.” Microbiome 4.1 (2016): 1-15.

TAGGED : , , ,

Leave a Reply

Your email address will not be published.

Virginia Davies, CEO
“We the people” must come together and make some real change. Read this message from our CEO and social entrepreneur, Virginia Davies.