Fast running woman in the forest ocr train outside

When we begin to work out, most of us will get a gym membership. We’ll jump to this decision because of a lack of time, a lack of self-confidence or simply because it’s become norm, perhaps thanks to the legacy legacy of ancient gymnasiums and training grounds. There’s a certain irony in needing go to go to a place just to be active.

The one thing we hear little about however, is the bad side of exercising indoors. Limited air supply and air toxicity due to mold particles and airborne bacteria are only a couple of known downsides. For an obstacle racing athlete a gym can be a subpar exercising environment for a bigger reason – the inability to simulate real obstacle race terrain and conditions.

On the other hand, the outdoors has long been proven to be beneficial not only for your body, but the mind too. Those benefits are countless, especially for obstacle racers. With the weather warming up, now is a great time to take your next training session outside and we’re here to convince you of it.

Significantly better air quality

It’s a poorly kept secret that in urbanised areas old buildings have a high humidity concentration. In Europe it is often the basements of these buildings that tend to be transformed into gym facilities and unfortunately these are often polluted by toxic exhaust fumes (sulphur, carbon monoxide, asbestos etc.), microbes and most importantly mold. All of these pollutants can affect your performance. For example, speaking of short-term effects, they can trigger asthma[1] and other respiratory problems. Since breathing is a key element in any athletic activity, obviously any impetus to breathing will also hinder performance. Although this might sound crazy, the negative effects of exposure to higher concentrations of these pollutants are well documented[2]. We’re just very good at omitting the problems which are not seen by the eye.

But my gym has air conditioning, you might say. Eeek. The typical air-conditioning systems found in indoors facilities, can only filter out a small amount of pollutants, if any at all. Try to be fully present the next time you go to the gym – how does the air and the atmosphere feel when you enter? Whenever I enter the gym, and I’ve been a member of several franchises, there’s always that same feeling – I instantly know that this is not a place where I can perform my best. Not to even mention how poor quality air can reduce your endurance during more longer workouts.

Restores ionic balance

Training outdoors will not only help you avoid toxic and microbial pollutants, but it will also boost your mood, help you de-stress and it will restore your ionic balance. Why does this matter? The closed up rooms and buildings we spend most of our time in, all have wiring, wifi and other technology that produces electromagnetic fields (EMFs). These are positive ions which our bodies tend to ‘sponge’ up and store because of the natural opposite conductivity. However, positive ions then act as a nervous system stressor causing headaches, fatigue, worsening depression, and various problems with skin, eyes and other organs. Interestingly, there are some hospitals in the UK which have introduced air ionisers in their systems to help improve patients’ recovery and to avoid the serious health issues EMF environments might cause[3].

In order to restore your ionic balance, you need to literally ground the body. This transfers positive ions and replaces some of them with negative ones. Think of your body as a conductor which is open to different electromagnetic fields, and you can reset the conductivity by introducing more negative ions through entirely natural surroundings: dirt, grass, stones, water – that’s why it feels so refreshing to be outdoors. To escape our daily, EMF- rich world. Such conditions are essential for athletic performance and will improve recovery rates as well.

A treadmill run is a poor simulation of a trail run

There’s a world of difference between these two and, if you’ve ever done a trail run or an obstacle race, you might already be nodding along. It’s the difference between running on a flat, consistent and shock absorbent surface, where your foot can land perfectly every time, and between a unique, muddy and unpredictable terrain. Trail running can lead to misplaced feet, twisted ankles; the shock absorption is totally different from a treadmill as it spreads to both your muscles and ligaments. A treadmill won’t get you strong enough and versatile to be ready for this type of running. How often will you find a consistently flat trail outside? The outdoors is often an unpredictable mix of hills with variable inclines that also come on faster than they would on a treadmill. In a race, you’ll battle with the grass feeling slippery under your foot, your shoes being full of mud and lacing in grip. Can you really prepare for these conditions on a perfectly clean treadmill?

Few conventional gyms these days have ropes, monkey bars, tires and other equipment which can bring your training closer to the real obstacle racing experience, though arguably still not close enough. Some experienced athletes and elite racers like Patrick Austin of HEXT, who we recently interviewed, design their own obstacle courses in their backyards, to better prepare for the reality of an obstacle race.

Temperature and acclimatisation

The amount of calories which you tend to burn while training outside, especially in colder climates, is a lot higher than what you’d burn indoors. Alongside this, climate acclimatisation and getting used to harsh, colder conditions is another huge part of training for obstacle races.

During a race your skin will be exposed to the conditions. More often than not, you’ll might run for miles in wet clothing. This puts your body under stress and if you’re not prepared, in spring/autumn conditions (in arctic circle to subtropic zones), you can get hypothermic. Same applies to subtropic climates and steaming hot environments – will your body be used to cooling itself down efficiently?

Training inside a gym with extremely unnatural temperature adjustments will not prepare you for any of this. This is by far the biggest disadvantage of training indoors. Less experienced racers first complain, not about the physical strain of the legs hitting the ground or generally tired limbs, but of how cold or unbearably hot it was.

To prepare for both extremes you should take your training outside. Expose your body to a cold river, lake or sea water for an extended amount of time. Though remember that this is training, so pushing yourself only just past your limit is good enough. If you’re dead set on staying indoors, you might at least want to try taking cold showers. I actually find cold showers far more pleasing, especially if I’m trying to cool down after a run or countless burpees. Similarly, if it’s a hot climate that you need to adjust to, you should start training in similar conditions.


One of the best things you can do as an obstacle racer is to take your training outside and test it out on real terrain. If you want to improve your performance and dominate the race obstacles, you should train like you’re in a race.


1. Ambient Air Pollution and Adult Asthma Incidence in Six European Cohorts (ESCAPE) –
2. Fine Particulate Air Pollution and Mortality in 20 U.S. Cities, 1987–1994 –

3. Air ionisers wipe out hospital infections –

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