The Atlantic Ocean's surface temperature is at a record high for this time of year while Antarctica's sea ice is at an all-time low.  Earth just broke records for the hottest day, the hottest June and is pending a record for the hottest ever recorded July.  Amongst the countries setting records highs are China, India, and Spain, as well as the U.S.

In Louisiana, Baton Rouge recently saw it's hottest day on record and New Orleans is broiling.  What does this mean for runners and walkers?

Consider this definition and explanation from the National Weather Service:

The heat index, also known as the apparent temperature, is what the temperature feels like to the human body when relative humidity is combined with the air temperature.  This has important considerations for the human body's comfort.  When the body gets too hot, it begins to perspire or sweat to cool itself off.  If the perspiration is not able to evaporate, the body cannot regulate its temperature.  Evaporation is a cooling process.  When perspiration is evaporated off the body, it effectively reduces the body's temperature.  When the atmospheric moisture content (i.e. relative humidity) is high, the rate of evaporation from the body decreases.  In other words, the human body feels warmer in humid conditions.  The opposite is true when the relative humidity decreases because the rate of perspiration increases.  The body actually feels cooler in arid conditions.  There is direct relationship between the air temperature and relative humidity and the heat index, meaning as the air temperature and relative humidity increase (decrease), the heat index increases (decreases).

HEAT INDEX CHART:

RECOMMENDED GUIDELINES:

In addition to the facts and charts provided by the National Weather Service, check out this information on hydration and guidelines vetted by the NCAA to help you determine if you are properly hydrated.

 NCAA Hydration Standards and Protocol: