Thermoregualtion In Racing

The physiological challenges faced by racing drivers when it comes to the heat and what can be done to minimise this.

Coping with the heat when competing in any sport is a challenge. It puts our bodies in a constant battle to maintain core body temperature in order to be able to survive and perform against the environment and the ability to maintain the desired workload when every muscular contraction generates heat.

Now in many sports this can be a challenge alone, in motorsport that is enhanced. In nearly all forms of racing and especially at higher levels we are asking drivers to be able to perform for up to 2-3 hours at a time while maintaining their performance level, concentration, decision making and reactions. 

Ordinarily in conditions that are hot, humid or a combination of both the body will have more than one method of helping to remove heat from the body: 

-       Conduction: The transfer of heat from the body to another surface or object if it is cooler.

-       Convection: The loss of heat from the movement of air or water molecules across the skin. This is dependent on the air or water flow.

-       Radiation: The transfer or heat away from the body to another object without any physical contact.

-       Evaporation: The conversion of fluid (sweat) to a gas as it evaporates from the skin.

 In order to function at our best we need to be able to maintain our core body temperature to as close to normal (37 degrees c) as possible. Any increase in this can lead to a drop in performance and the onset of fatigue, get close to 40 degrees and it can be life threatening. 

Therefore as we spend time in hot environments we will see an increase in sweat rates to enhance evaporative heat loss, if moving we will also get loss through conduction as we have air moving over the skin helping to take heat away. Its why people often look red when exercising in the heat to as more blood is directed to the capillary blood vessels in the skin to help with the heat transfer. 

In motorsport though these main methods of heat loss in conduction and evaporation are significantly reduced. With the drivers having to wear fireproof base layers, triple layer fireproof race suits, gloves and boots that cover every inch of skin from the foot to neck, then a fireproof balaclava and a racing helmet there is no surface skin left for conduction to occur effectively. The multiple layers of clothing also blunt the effectiveness of evaporative heat loss as the sweat then needs to get through the material before it can evaporate. 

So exercising even outside in these conditions would be pretty hostile for the body, add on top that in most GT or saloon racing cars temperatures can get as high as 60 degrees centigrade and in single seaters its not much cooler as most of the airflow passes right over the driver in the cockpit and it becomes a very hostile environment, one where you are then asking them to continually move which creates more heat from the muscles and to maintain concentration, reactions, decision making and physical strength. 

Even in moderate conditions like you might get on a British summer race meeting of low to mid twenty degrees drivers can often lose 2-2.5kg of fluid in a stint. Go somewhere hotter or with more humidity like Singapore, Malaysia, Brazil, Bahrian and this can increase to 4-5kg of fluid. 

 This loss of fluid can be as much as 6-7% of a drivers bodyweight, so putting them in a position that would ordinarily be classed as severely dehydrated. Enhancing the risk of heat exhaustion or heat stroke. Its widely considered a 2% drop can lead to a reduction in performance. 

SO WHAT CAN BE DONE?

In order to try and combat this there are a range of strategies that we can put in place to either try and minimise the effects of the heat or to give ourselves more of a buffer against a rise in core body temperature. Some methods being far simpler to implement than others.

Ahead of the event one option is to look at heat acclimation. In essence getting drivers to train in heat or environmental conditions similar to those of the race. Even better to spend time in that location training before hand. This is effective and used in many sports, however with motorsport can be harder due to the frequent travel demands and often constantly changing environmental conditions of each race. Limiting the time in which to do this and the time that can be spent there.

Another area is pre-cooling. Essentially trying to lower a drivers core body temperature slightly before they get in the car, giving more of a buffer against it rising above the 37 degree baseline and beginning to generate increased sweat loss and beginning to impact on performance. In order to help pre-cool the driver a few methods that can be used are:

• Staying in the cool or shade for as long as possible, you will often see drivers sitting in shade or with umbrellas to keep the sun off them. 

• Use of cooling vests, cool towels and ice packs. These have some use although the impact is dependent on where they are places. Cool towels round the wrists and neck can be great as blood vessels close to the skin to get effective conduction. The cooling vests have a bit less impact as asking them to work through a fireproof base layer and an area of the body where major blood vessels are deeper.

• Use of cold drinks and ice slushies. Again impact can be brilliant, but has potential too that can feel uncomfortable when then in a car and facing the forces that drivers face.

During the race the options to influence the thermal balance are limited. We can add drinks to the cars for driver to take on fluids but these are limited in size and in many cars often warm very fast. There is one area though that a company Walero have made a break through on which is the base layers drivers wear. Having switched up the materials used and taken technology from NASA their base layers store and release heat when needed keeping the skin drier and driver cooler. A bold claim to make but one that they have gone to great lengths to prove and when put to the test against other base layers in identical conditions and with the same driver. The results were a rise of only 0.6 degrees c wearing Walero vs 1.5 degrees (0.9 degree difference) in the standard base layer, average HR was 8 beats.min-1 lower, and 0.2kg (40%) less fluid loss over the same hour long stint. All of which helped reduce the strain on the body and improve performance and maintain concentration. In essence being smart about the race suits and base layers a driver wears can have a big impact without any extra effort. 

When competing on multiple days or having to recover from qualifying to a race the next day the post race strategy is key as well. Getting the drivers core body temperatures back down and under control, replacing fluid and electrolytes and rehydrating them are key. Here tools such as ice baths, cooling sprays, cold towels and strict rehydration protocols are key to implement. 

SUMMARY

In summary the thermal challenges faced by racing drivers often aren’t obvious, however they are significant. They will play a crucial role in determining performance especially over longer stints. 

Therefore to maximise performance a pro-active approach is needed. This means when possible doing what you can to acclimatise to the conditions, even if it is just getting to spend a day or two at the location before hand and getting in some physical activity. 

It means doing what you can given budget, time, space etc to keep the driver cool before the race and to try and lower their core body temperature to create a bigger buffer. It means being smart about the choice of racesuits and choice of base layer used to help minimise thermal strain and prolong the rise in core body temperature and reduce sweat rate as mush as possible to avoid dehydration. 

Finally it means maximising post event recovery. Paying particular attention to retuning the core body temperature to normal levels as quickly as possible and putting in place measures to replace the fluid and electrolytes the drivers have lost throughout the event or stint as efficiently as we can.