Body Temperature
Runners and racers vary widely in how weather and racing impacts their body temperature. I tend to struggle immensely with controlling (reducing) body temperature, running in warm weather.
Here are some tips and tricks for staying cool during a race.
Clothing
When in doubt, wear fewer clothes at the beginning of a race. I say that if I am comfortable at the beginning of a race, I am going to be uncomfortable later in the race. Races have gone best for me when I am shivering a little or quite cold at the beginning of a race.
Wear disposable shirts, gloves, and arm warmers that can keep you warm at the beginning of the race that you can discard as you warm up later in the race.
You can often find old shirts in your home or at a thrift store that you can dispose of during the race. Also you can find very cheap packs of gloves (often <$1 per pair) at a hardware store. You can make arm warmers by cutting off the toes of old full length gym socks.
For very cold or wet races, it is important to dress in layers, and in clothing that keeps you dry. Warm gloves and hat are most important, since most body heat is lost via head, hands and feet.
For wet races consider putting duct tape over tops of shoes to help keep feet dry. Also experiment with different socks to prevent blistering if your feet get wet.
Ways to Stay Cool During Warm Weather Races
Ice: If possible, find ways to apply ice to major blood flow places on your body during a race. This includes applying ice (or ice water sponges) to your head, chest and wrist areas. It has worked well for me to have small ice bags to put under my cap to keep my head cool. This method requires a dedicated support team/family member.
Water: Another way to keep cool is to keep as wet as possible during the race. A method to do this is to soak your running shirt in ice water immediately before the race. Also, I pour at least one cup of water over my head and upper body at each water stop. Keeping your body wet helps keep it cool, and helps regulate heart rate and body temperature.
Sauna: A method to use during training to help acclimate your body to a hot race is to spend time sitting in a sauna (or working out in one) a few times a week for a few weeks leading up to the race. Doing this has helped my body adjust to working hard or simulating a race in a hot climate. This adaptation has made any race day temperature seem cooler than it actually is, as my body acclimated to the warmer environment of a sauna.
It is important to research proper sauna usage, to not overdo it, by staying in saunas too long, or too frequently which can lead to negative health impacts.