Human Limits

The big news in the first game of the NBA finals was the air conditioning failure in San Antonio. This surely contributed to Lebron James cramping up and being unable to play the final four minutes of the game as the Spurs pulled away.

As the game wore on, ice packs and cold towels were used in an effort to keep the players cooler, and Lebron apparently changed his uniform at half-time to try to cool down. Might there have been a better strategy to deal with a warm and humid environment with a temperature that was apparently in the 90s at game time? The simple answer is yes.

When our core temperature increases a degree or two, the internal thermostat in our brains activates nerves to sweat gland and we start sweating. The internal thermostat also activates nerves that dilate the blood vessels in our skin and blood flow to our skin increases. If the sweat evaporates the skin stays cool and the blood flowing to the skin cools off. This evaporative cooling system lets the heat generated inside the body get out. When we exercise we produce more heat, and this heat transfer system is even more important.

So, the problems for Lebron and his colleagues included the heat they were producing while playing, the temperature in the building and the reduced ability of their sweat to evaporate due to the humidity. All of this then probably his lead to a viscous cycle of higher body temperatures, more sweating and more skin blood with the extra sweating not helping to cool the body but instead causing more fluid losses. Any extra skin blood flow might also have led to less blood flow for the player’s muscles.

So, what might have been done differently? First, wear less clothing. Any observer of the modern NBA can’t fail to notice the extra clothing and gear a lot of the players are wearing. All of this extra swag creates a microenvironment that makes it harder for the sweat to evaporate and cool the skin. So, if happens again Lebron, ditch the tights. Second, forget the ice and cool towels, they may feel good but if they are too cold they might actually reduce skin blood flow and make core temperature higher. Third, get some fans. The key to the evaporative cooling system I described above is evaporating the sweat. My bet is that there were high capacity fans somewhere in the arena and the best strategy would have been to have players take their shirts off on the bench while the fans created the airflow needed to evaporate their sweat and keep them cool and ultimately in the game.