The best strategies to keep bodies cool in a heatwave, according to researchers
Posted on 21 July 2016 by John Abraham
As we hit high-heat season in the Northern Hemisphere, it is useful to clarify tactics that can be used to help maintain healthy body temperatures. These tips are not commonly known and can be adopted by anyone, anywhere. While I am a climate scientist, my funded work is in the area of heat transfer, particularly in the human body. I work with medical companies to maintain healthy body temperatures during surgeries or other situations. I also deal with scald burns and I often serve in burn injury litigation.
Here are some key tips. First, avoid hyperthermia in the first place – drink plenty of fluids, avoiding direct sunlight, trying to get a respite from heat each day, avoiding physical exertion during the hottest parts of the day are all great suggestions. But, if you need to lower a body temperature, Dr. Robert Huggins, VP of Research and Athlete Performance at the Korey Stringer Institute suggests:
The general rule is to cool as much of the body’s surface as possible …. the larger the area you cool and the colder the device you use to cool it the faster the cooling rate. An appropriate goal is to use a method that cools at a rate of 0.15°C per minute. This can typically be achieved by immersion techniques using a tub or other basin filled with ice cold water or via rotating cold ice towels over the body.
During exercise if there is limited access to the entire body (e.g. football or fire-fighters), cooling the hands, face and feet will help, and if possible, use a fan to increase evaporation from these surfaces. However, when heat stroke is suspected, these strategies are not nearly as effective as whole body methods; opt for immersion cooling.
So how do you know if someone is suffering from hyperthermia or heat stroke? A great resource is the Korey Stringer Institute, which lists many symptoms for heat stress such as fatigue, weakness, pale appearance, headache, nausea, vomiting, fainting, dizziness, and others. The heat stroke treatment they recommend, while geared toward athletes, is still useful for the rest of us.
In many actual situations, full body immersion isn’t possible. What can people do then? Well, there is extensive evidence that supports the cooling of the hands, face and feet. The technical term for these areas is glabrous (non-haired). These areas are excellent at transferring heat and in fact, the body can increase the blood flow to these regions which, when cooled, flows back to the body providing core cooling.
One paper looked at the impact of cooling athletes’ palms on their ability to recover between exercise sets. They found that “palm cooling hastened heat removal”. Another publication, just out in 2015 in the journal Wilderness and Environmental Medicine compared cold packs applied to the neck, groin and armpit with cold packs applied to the cheeks, palms and feet. That study found that applying cold packs to the cheeks, feet, and hands almost doubled the cooling effect. They write: