Thermoregulation and your rain jacket
Thermoregulation is a physiological mechanism of great importance in cyclists’ performance, which must be monitored, especially in bad weather conditions, either winter or summer.
The skin is one of the main responsible of regulating body temperature. We tend to pay attention to thermoregulation in summer, in extremely hot conditions, but we forget to do it in winter, when it becomes even more important, if possible.
To give some context, the intensity in which a cyclist works influences his general thermoregulation scheme, this is, the more watts we are moving the more calories we are burning.
When the body breaks down food for energy to perform an activity, only 20% of that energy is used to perform, the remaining 80% is lost as thermal energy.
Once this heat reaches the skin, it is transferred to the environment. If the temperature outside is lower than the body, the heat loss will be much higher.
In addition, evaporation by sweating is the most important form of heat loss.
Apart from these we add the third factor: heat loss increases considerably in humid environments.
Hence the importance of being extremely careful when choosing our layers of clothes on the bike. A bad choice of garments can even lead to hypothermia and dehydration, which can be more or less serious depending on their grades, but which in any case will directly affect our performance on the bike.
Most of us remember Van der Poel hitting the wall in the World Championships in Yorkshire 2019. The Dutchman, one of the favorites to victory, saw how his options disappeared 10 kilometers before the finish line.
Many were the factors that influenced this terrible circumstance, but some physiologists blame part of the problem on the terrible day of rain and cold.
The enormous loss of heat, excessive sweating and little perspiration due to the raincoats used in search of a heat that never came, contributed to dehydration, hypothermia and a definitive implosion of the rider.
Hydration, as important and complicated as forgotten, deserves a chapter on its own and will be discussed in later entries, with the help of our nutritionist, Carlos García Pelayo.
But let's focus this time on thermoregulation and the choice of our clothes.
Our first layer should be able to eliminate sweat and wick it, keeping us warm. A first layer which does not perspire enough and/or doesn’t wick that moisture correctly will cause heat loss to accelerate considerably.
We all have felt at some point how cold takes hold of us, being impossible to getting warm, no matter how many layers we wear.
If the first layer is wet, nothing we can wear will help.
The same will happen with the outer layer, which should keep away wind and rain being also breathable.
Hence the importance of paying special attention to your windbreaker and, especially, to your rain jacket.
We tend to use any waterproof jacket, basically a plastic garment which protects us from rain just like a supermarket bag would do.
But the membranes of your outer layer must have the ability to keep water out, while wicking moisture away from the body. How many times have we ridden in the rain and back home our clothes are more soaked in sweat than if we hadn’t worn any jacket?
One of our favorite pieces is the Shield Jacket, made by the Danes from Pas Normal Studios who, for obvious reasons, are experts in extreme weather conditions.
This jacket has a membrane called c_change® (Schoeller®)
Inspired by nature, the c_change® membrane works on the same principle as pine cones. They open when the outside temperature rises and close again when the temperature drops.
The membrane of this jacket reacts in exactly the same way to environmental conditions. Not only temperature but also humidity of the air and body are taken into account.
At higher temperatures or during sports activities, the c_change® membrane structure opens in response to elevated body temperature. Excess heat and humidity can escape outside. In the cold, or with low activity, the membrane remains closed.
The membrane adapts to the conditions since it is highly breathable and eliminates moisture and excessive heat. In addition, it offers ideal heat retention according to the situation, being windproof and waterproof.