There’s a saying in Virginia that “if you don’t like the weather, wait five minutes, it’ll change.”
Well, the weather has changed in the course of a few days from a cool and rainy late spring to a sunny, warm and humid early summer and with it the conditions that runners face when they step out the door to start their daily run.
Summer, like winter, presents its own climatological challenges to runners with the foremost, and most potentially dangerous of them, being the combination of temperature and relative humidity.
The human body normally cools itself by perspiration, or sweating. Heat is removed from the body by evaporation of sweat. A high relative humidity reduces the evaporation rate, resulting in a lower rate of heat removal from the body and bringing about the sensation of being overheated.
The calculation of this combination of temperature and humidity is called the heat index (it is also sometimes referred to as a ‘real feel’ temperature.) For example, let’s say the temperature is 86 degrees and the relative humidity is 60%, that will result in a heat index of 91 degrees or what is considered an ‘extreme caution’ zone. But if the temperature remains at 86 degrees, and the relative humidity increases to 90%, the heat index rises to 105 degrees or what is considered to be in the ‘danger’ zone.
If the body cannot properly cool itself a person may experience muscle cramping from the heat, heat exhaustion, or in the more extreme form, heat stroke.
There are several precautions runners can take to limit their risks from the summer heat and humidity.
1. Stay hydrated. Carry a hand-held or waist-belt hydration product from Nathan or Amphipod filled with an energy replacement drink such as Nuun or SKRATCH that replaces electrolytes lost through perspiration. Also drink early and often during your workout, not when you start feeling thirsty.
2. Wear loose fitting, well-ventilated, light colored clothing.
3. Wear a hat to protect your head and face from the sun, sunglasses to protect your eyes from the glare of the sun and a sunscreen with an SPF of 30 or higher. You can also wear Buff neckwear that offers UV protection for your neck. There is also apparel that also offers UV protection from the sun.