This is posted from http://www.enjoywinter.com/skipost-archives
Would you please respond to the issue of wearing hats to help maintain core temp and thus not jeopardize performance. Our middle school & high school girls are into looking good with brightly colored headbands that leave much of their hair & head exposed to the elements. Today at the JNQ Sprint races in Wausau we had pouring rain (it could have just as likely been heavy wet snow) coming down that was totally saturating their head/hair as well as their race suits. While coaches are concerned with the wax on their athlete's skis, it does not seem like they are as concerned with lessened performance due to inappropriate dress. I am not talking about sunny 30+ race days. I was always taught that if core temp was maintained or even increased - the extremities (legs/arms and the muscles in those legs and arms) would perform at a higher level than if the body was chilled and the blood was being shunted to the core. Is this old school thinking? I believe if an expert responds to this, I have a better chance of being listened to when I tell them to put a hat on!
Yes, the human body performs best when its core temp remains around 98.6 degrees Fahrenheit (37 degrees Celsius). Too cold (or too hot) and performance quickly drops. We lose heat through conduction, convection, radiation and evaporation. We constantly release heat in the form of radiation. Conduction occurs when our bodies give away heat to that other object that we are in contact with that has a lower temp, like snow or air particles. Convection occurs when we transfer het to air particle through motion i.e. "wind chill" Finally, when as we sweat, ( or get wet) we transfer heat through evaporation, as water on our skin transforms into a gas. Since our bodies naturally give away heat to colder, active particles, air particles in wind, and water particles (snow and rain) can accelerate that effect.
To combat rapid cooling, we shiver to generating heat by exciting our muscles. In the cold many parts of the body blood vessels in our skin tissue constrict, or tighten up to keep blood away from the cold outer layer of the body and helps circulate warmer blood to our core areas. But this tightening is not good for peak performance and racing.
Why a hat? Because areas around the head, neck, chest and groin don't constrict as effectively as the smaller ones near the skin and thus more even more susceptible to heat loss. Furthermore water is denser than air, so it absorbs more heat (up to 32 times more) than air. So when you are skiing in rain or snow you can get hypothermia quicker if the rain or snow is falling on your uncovered head and neck.
That's why Nordic racing attire includes a hat and often neck gaiter.
When your core temperature down to 95 degrees or below it is called hypothermia. When your re-warming reactions are not enough to overcome the cooling process, hypothermia can set in and skiing performance will decrease quickly. Mild Hypothermia includes shivering, goose bumps, difficulty with complex motor skills Moderate Hypothermia includes violent shivering, sluggish, speech problems, difficulty with fine motor skills. Severe Hypothermia includes rigid muscles, dazed, shivering has stopped, blue skin, erratic heart beat.
So dress properly, starting with your first layers and finishing with a hat and neck gator to race better.
Andy at SkiPost
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