Why the best warm up may be keeping cool
When it comes to athletic performance one thing that we can’t influence is the environmental conditions that drivers and riders are faced with. As performance coaches and athletes, we can’t control the humidity, we can’t control the intensity of the sunshine, the wind, rain, or the temperature…. or can we? And can we limit the impact that they can have on performance?
THE BACKGROUND
Before we delve into answering those questions it’s important to consider just what impact the environmental conditions can have on the human body, the physiological responses and how these impact on performance.
The human body is brilliant at creating its little comfort zone called homeostasis in which it is happy to perform in. A steady core body temperature, sleep routines and more all driven by our circadian rhythms and our normal environment.
While we try to push our bodies outside of this little comfort zone and elicit adaptations that will raise the homeostasis bar for a variety of physiological variables with training, this little bubble of comfort that our body likes to operate in can be disrupted by the environment around us too.
The environmental conditions that we are facing will have a big impact on our core body temperature, hydration levels, sweat rate and concentration, energy expenditure, resting heart rate and more. While both heat and the cold will have an impact here, in this instance we are going to focus on hot and humid conditions.
While when we exercise, either training or competing our movement and constant contraction and relaxation of the muscles generates large amounts of heat. This in turn heats up our blood and begins to raise our core body temperature…starting to push the body out of the little comfort zone it likes to operate in. As the core body temperature begins to rise there are several mechanisms that the human body will subconsciously implement to try and bring the core body temperature back to its state of homeostasis.
Two of the main methods the body uses to achieve this, while there is an increase in blood flow to working muscles during exercise in this scenario and in hot environmental conditions at rest, we also get an increase in blood flow to the capillaries (smaller blood vessels near the skin). This increase in blood flow to the capillaries allows for the loss of heat to lower the core body temperature through convection of the cooler air passing over the skin’s surface.
At the same time when we get an increase in core body temperature, we get an increase in the rate at which we sweat. The increase in sweat rate will draw heat from the core away to the surface of the skin where it is then lost through evaporation. While an effective cooling method this does mean that we lose both fluid and electrolytes in the process.
However, the hotter the environment the greater the increase in the core body temperature, this means that the body has to work even harder to try and counter this. There are limits though to how much heat can be lost through convection and evaporation, once we have hit these limits core body temperature will begin to slowly increase.
An added extra complication is humidity. If we are training or competing in humid environmental conditions, we reduce the effectiveness of evaporative heat loss as moisture levels in the air become closer to those on the skin. This will mean that controlling the core body temperature becomes harder.
SO WHATS THE DRAWBACK?
A valid question as on the face of it there doesn’t seem to be anything wrong here. Our body is getting warmer, but it’s also got mechanisms in place to cope and counter this.
However, heat presents us with a number of problems. The most serious of which are that when our core body temperature gets to around 40 degrees Celsius there are severe health risks both from a cardiovascular and neurological perspective…the good news here is that outside of very extreme conditions the body is excellent as preventing us from getting to this point.
The bigger issues that heat and humidity pose are as follows:
- Muscular Fatigue: When our core body temperature and the temperature of the muscles increases too much outside of out comfort zone, we get a reduction in muscular power and an increase in muscular fatigue. This means impacted force production capacity and reduced time before lap times and performance in the car or on the bike begins to suffer. Also increasing the chance of making mistakes and errors.
- Dehydration: The second issue that faces us is that the increase in sweat rate means we are losing fluid from the body and from our bloodstream. While this is perfectly normal and in short duration competitions not a problem as the volume lost is small. Over longer durations and in harsher environmental conditions the volume of fluid lost can be significant. Well beyond the percentage of bodyweight that is associated with dehydration. As with the core body temperature rise a state of dehydration will impact our force production capacity, muscular endurance but also our cognitive performance and have a negative impact on our decision making, co-ordination and reaction times. Therefore, increasing the chances of errors and mistakes. There is one further impact though, as we lose fluid our blood volume drops, and our blood becomes more viscous. This then impacts on the ability of our body to pump blood to the muscles and to the skin, reducing our ability to not just lose heat but also to provide the energy to the muscles to fuel contractions. It will also mean that our heart is having to work harder, and we will see an increase in heart rate to account for not being able to pump the same volume of blood with each beat.
When we look at the above factors, we can see that the rise in core body temperature and the hot, humid conditions will have a big impact on performance, both in training and competition. Therefore, if we can limit these increases or create more of a buffer before our core body temperature begins to rise we can positively impact performance.
WHAT CAN WE DO TO KEEP THE CORE BODY TEMPERATURE LOWER?
So when we start thinking about how we can control core body temperature during competition one of the main factors we can use is pre-cooling and trying to lower core body temperature before hand to create more of a buffer during competition before there is an impact on performance.
While there are a wide range of methods that we can use to achieve this, the practicality and ease of application can vary significantly and is also impacted by each individual and their preferences. Below are some of the potential methods ranging from the simpler and easier to implement to the more complicated and harder to administer.
The pre-cooling strategies that we can use prior to competition are:
- Ice drinks: One of the simplest methods that we can use, by getting athletes to consume chilled or ice-based drinks such as slushies that will sit in the stomach, we lower the core temperature from within. While a simple and easy to administer method there can be drawbacks to this such as the palatability of the drink and how it sits in the stomach when competing. In this instance where an iced based drink will work best, if it isn’t palatable or the individual isn’t comfortable with it in the stomach then a chilled drink can be a better option although has a lesser effect at lowering the core body temperature. Both methods do influence hydration as well which is important in hot and humid environments.
- Cooling Vests: A commonly used method the colling vest worn prior to an event can have some impact on lowering core body temperature. However as cooling vests are placed across the main bulk of the torso, they aren’t near any of the major blood vessels near the skin and will generally have a layer of clothing between the skin and vest too. This means that there is limited effectiveness of the cooling although can provide a degree of placebo effect.
- Cooling neck and wrist wraps: These work in a similar manner to the cooling vests and use conduction as a means of lowering the core temperature by drawing heat away from the body. Simple methods to administer this are frozen of cooled towels placed around the neck or the inside of the wrist. While not as easy to administer as a cooling vest these provide a better cooling impact as the blood vessels are closer to the skin at these points. This means that there is a much greater heat transfer from the blood that is pumped from the core.
- Cooling mists are an additional cooling method that has been utilized in several team sports where competing in hot humid environments as a method of reintroducing evaporative and conductive heat loss. This method essentially requires the athlete to walk or move through a cool water mist, for example in rugby or football it is often used running though the mist as players exit the tunnel. While this covers the players in a fine layer of cool water that is cooler than the environment it draws heat away from the core body.
While these have a positive impact and can be a great way to administer a cooling strategy to a team of players where you need to cool many individuals, plus where you have the space at a stadium. For individuals such as drivers this is an expensive and difficult method to administer. There is little room for the fans and mist water spray required within the paddocks and both the cost and complexity to administer this means its not the optimal method.
- Ice Baths, these can be an effective method to administer pre-cooling and post event cooling to athletes. While initially this method used to be complex and expensive due to the lack of availability of ice baths. With the availability now of some of the pods such as Lumi that can be easily collapsed down and transported it has become far easier to administer. As we can chill the water to a cool temperature and immerse ourselves in it, even in very hot and humid environments we can re-introduce both conduction and convection-based cooling. The added benefit is that we get the cooling effect across the whole-body maximizing heat transfer and heat loss.
The big challenge with this method is that it isn’t the most comfortable to begin with and will take some time to get used to, therefore can require some acclimation with an athlete before using it at events.
- Shade, this might sound overly simple. However, it can make a big impact for drivers. When trying to minimize core body temperature increases before getting into a hot car staying out of the sun as much as possible before hand can play a big role. This doesn’t need to be overly complicated too and can be as simple as staying in the garage for as long as possible or by standing under an umbrella while on the grid and utilizing screen shades or umbrellas to try and keep the cockpit of the car temperature down.
While as I say this is one of the simpler methods it can help keep the environment immediately around the driver a few degrees cooler and keep core temperature down by reducing the radiation from the sun’s UV rays.
HOW CAN WE IMPLEMENT IT IN THE WARMUP?
So, while competing in hot humid conditions building in pre-cooling to the warmup routine can have a marked impact on performance and create more of a buffer to core body temperature increasing. Thus, creating more of a buffer before fatigue or a drop in cognitive performance kick in.
While we don’t want to move away from a physical warm up and this still needs to be part of the process, in these environmental conditions where we can we want to look at performing the warmup in the shade or in a cooler environment. This will allow us to get the benefits in terms of firing up the central nervous system, increasing blood flow and improving range of motion while minimizing the thermal impact.
Alongside this the cooling strategies that can be implemented will largely depend upon the individual and on the space and financial constraints, therefore there is no set protocol. However, in environments where there is a mild thermal strain or where time, space and budget are minimal utilizing the combinations of cool drinks, shade and cooling neck / wrist wraps can be an effective manner to start to reduce core body temperature.
In an environment where there is a greater thermal strain and where space and cost are less prohibitive, we can start to add in utilizing a ice bath before our physical warm up so we are starting from a lower core body temperature, and also build in the use of ice vests as well when on the grid or in the garage.
No matter which method used, or combination of methods used we are only looking for small changes in core body temperature, but this can make a huge difference. As with anything else a key element is to try these in testing or before we reach competition. Every athlete and individual is different and will have different preferences as to the method used and therefore the intervention strategy has to be built around the individual alongside the science.