Wow. Summer is really here. When you wake up and head out for a morning run and its already 80 degrees and the humidity presses in like a warm blanket, you know another Austin summer is underway. Runners typically slow down considerably during this season. Physiologically, the body simply can’t perform as well in the face of high heat and humidity.

Stay hydrated and use caution when running in the heat

Hot weather raises the body’s core temperature, and blood is shunted away from working muscles to the skin’s surface in order to sweat, thus providing a cooling mechanism. However, high humidity throws a wrench in the works by preventing sweat from evaporating from skin—thus hampering the cooling effect. Even low levels of humidity make running difficult by increasing fluid loss and dehydration. This actually leads to “thicker” blood, which requires more energy for your heart to pump—a condition called cardiac drift: the heart needs to pump more quickly and forcefully to move viscous blood.

So, needless to say, summer running has risks. Run too hard on any given day from June through September and you risk a number of heat illnesses, including heat cramps, dehydration, heat exhaustion and heat stroke.

The first two are easily remedied: stay hydrated and take in plenty of electrolytes. With heat exhaustion, medical experts advise getting out of the sun into a cool environment and drinking cold fluids. But heat stroke is another story. Heat stroke occurs when the core body temperature rises to 105 degrees or more. When that happens, your body begins to shut down. You may become disoriented, clumsy, confused, and lose your balance. Another symptom is that you’ll stop sweating. This is not a laughing matter, and you should seek immediate medical attention, or if none is readily available, a cold bath or ice.

The good news is that not only does the body get better at dissipating heat and conserving electrolytes, but it produces more red blood cells and becomes more efficient at controlling core temperature. In essence, you adapt to the heat, and may find yourself even more efficient, come cooler fall weather.

Quick Austin summer running tips:

  • Run early before the sun comes out when the temperature is lowest
  • Run by effort, and don’t push the pace
  • Seek out shady trails
  • Embrace tech gear: it helps wick sweat away
  • Drink up before and after each run and carry fluids with you for runs longer than 60-90 minutes

Upcoming races: Freedom 5,000, July 4 at 8:00 a.m., Camp Mabry, Austin. Popsicle Run Four Miler, July 4 at 7:00 a.m., 5940 McNaughton, Kyle, TX. Capt’n Karl’s Muleshoe Bend Night Trail Run 60K, 30K and 10K, Sat. July 15, 7:00 p.m. at Muleshoe Bend LCRA Recreation Area, Spicewood, TX.