Every year, around mid-May, I lace up my shoes and head out the door for my usual morning run. Then I’m hit with a wave of heat and humidity . Ah yes, the all-too-familiar feeling of opening up a 400-degree oven to check on my frozen pizza—except the oven is just late spring in South Carolina, and I’m the pizza being burned to a crisp. Summer down here starts in May and ends around Halloween, so I’m no stranger to training through the heat . I fancy myself an expert, having trained through over a dozen summers to get in shape for fall cross-country seasons or marathons. In the past 12 years, I have only had to call someone to pick me up for fear of heat exhaustion once. I credit this streak of surviving summer training to my favorite hack: air-conditioning breaks. The concept is simple. When my heart rate gets too high or I feel overheated, I find a grocery store, gas station, or even my own apartment to stop in and spend a few minutes in the air conditioning.…