There are many aspects of your training and racing that you can control, but the weather is certainly not one of them. And whilst it is tempting to avoid training in inclement conditions, we may as well prepare ourselves for the worst on race day by training in all sorts! Especially increasingly, in the UK.

However there are many considerations when it comes to assessing risk and performance impact associated with weather. One thing you can control, is how well informed you are…

Weather can significantly impact performance and in extreme conditions lead to medical emergencies. However with some preparation and strategy adjustment you can still perform well in some challenging conditions.


Exercising in the heat increases our perception of effort, such that movement feels more difficult. In part this is a safety mechanism that discourages us from over exerting and causing ourselves serious issues from heat exhaustion. Fortunately our body is pretty good at protecting itself from damage, even if our egos sometimes aren’t. To dissipate body heat in high temperatures, our body will redirect blood flow away from our muscles to our skin. This reduction in blood supply to the muscles will obviously reduce performance and induce fatigue.

Training in the heat can offer some advantages. Heat training is sometimes called the poor mans altitude, as heat training can have some similarities to proper altitude training. The body adapts to heat by increasing blood plasma volume which allows greater capacity for red blood cells. This adaption can happen quite quickly, with measurable results in some athletes after just ten days of heat training.


Due to lower air pressure, being at altitude means there is less oxygen in the air available to be absorbed into the bloodstream. The lower blood oxygenation corresponds with a reduction in VO2 max. The effects of altitude of can be felt as low as 600m above sea level although many athletes are not affected until closer to 900m. Training at altitude produces a useful adaption, which is that it triggers an increase in the number of red blood cells. Consequently many elite athletes will use training camps at relatively high altitude when preparing for a race at near sea level.


As you might reasonably expect, training in the cold produces the opposite physiological response to exercising in the heat. Blood is again redirected, but this time away from the peripheries in order to maintain heat. When training in the cold, appropriate cloths are more important. Polyester clothing is preferable as it quickly wicks sweat away from the skin. Also wearing gloves and a hat will do a lot to reduce heat loss from the extremities.


Humidity impairs the bodies ability to lose heat through sweating, which will affect your heat tolerance and impede performance. One useful tool is the wet-bulb glove temperature, a method for measuring temperature which factors in humidity, solar radiation, wind movement and ambient temperature. This enables a reading that will estimate the aggregate effect of all these environmental conditions upon the human body. This technique is being increasingly adopted by sports bodies and event organisers to establish how suitable it is to race at a given location on a set day. If you are training in hot humid conditions then acquiring a WBGT is a good investment. You should also familiarise yourself with recommended guidelines in this respect.


Whist rain can make it hard to step outside, once we are out then it can be very pleasant training in the rain. As you would expect it will help keep you cool comfortable once you are warmed up. The issue arrises when it is both cold and wet, as once your body is wet it will be hard to retain heat. Being drenched in rain has the same cooling effect that your body is creating when it drenches itself in sweat. Being unable to retain body heat can lead to hyperthermia and other heat related complications. It is surprising how big an impact a good running jacket and appropriate headwear can make to your safety in cold & art conditions.

Air Pollution

This is a concern for many athletes training in large urban areas, there are several considerations when training in air pollution zones. The amount of time you are exposed to pollution pre-training matters. Driving for an hour in a heavily polluted city to reach a gym and then run on a treadmill probably makes very little sense (at many levels), and a shorter session that minimises pre-exposure may well lead to better training results. Planning your outdoor training time to be early mornings or late evenings is also helpful, as pollution is generally lower at these times. Consider the location you are actually training in and where possible arrange your route to give yourself some distance (even a small distance makes a noticeable difference) to the main sources of pollution, consider natural barriers such as tree lines. The decline in pollution levels is exponential as you move away from a road for instance. Whilst pollution is a consideration, there is also a case for pragmatism. Cutting out training sessions, or reducing exercise more generally in the broader population, is likely to have a more significant health and fitness impact than pollution exposure.


Different types of terrain provide different physical challenges and therefore opportunity for subtly different training adaption. It takes practice to run or cycle up hills. Likewise running on uneven surfaces utilises different muscles to a flat smooth surface but also presents a different injury risk profile. And as previously noted changing the altitude will make even an easy jog potentially feel much harder and therefore present an injury risk from form breakdown.

Variable Surface

Running on a firm, even surface like a road or treadmill can produce fast, consistent results, but may increase the risk of overuse injury. Conversely, running on variable terrain such as trails will increase stride to stride variability which will change pace and impact running economy. The risk of overuse injury is reduced but there may be an increased risk of strain through lack of (untrained) stability. Factors such as mud, sand or loose gravel will also affect performance and change muscle requirements.

In Conclusion

We can’t change the weather, but we can make use of it change training stimulus and therefore adaption. It can help us create “surrogate” conditions to better align our training to be more aligned to a specific race demands. Also we don’t have to always train in the same place. Being more thoughtful around location and the characteristics that different places offer, allow us to create different training sessions.

Of course come race day the terrain will have been predictable but the weather will always be a variable. Ultimately, the more varied weather conditions we have experienced in training the better equipped we will be to maintain performance when it matters.

Photo by Florian Schmetz on Unsplash

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