Running and exercising in warmer weather tends to be more taxing on your body and requires more energy to remain cool.

Most running experts suggest performance impairments of between 1.6% and 3% in marathon times for every 10 degrees above 55 degrees Fahrenheit.  The exact ideal temperature (approximately 45-55 degrees Fahrenheit) is debatable and based also on humidity.

When you’re not acclimatized to running in heat, it takes even more effort to keep your running pace.  This increases your risk of muscle cramping, bonking (hitting the wall), and/or being unable to maintain your goal pace (which leads to a longer finishing time).  Continue Reading