Running in the Cold

I've been running for about a year and a half, primarily 5-Ks at around 10-minute pace. I'm now training for a 10-K I recently signed up to run a half-marathon. Training begins in July in St. Louis, which gets very humid and hot. I've found that I struggle in hot, humid weather. What's the best way to get my body acclimated to running in the heat and humidity? I'm also concerned that I won't be able to complete the longer distance. Thanks--Kimberly

Hi Kimberly. Much of the challenge you are experiencing may be due to the drastic shift in weather in the Midwest in the past week. It went from a continuous weather pattern of 40- to 50-degree temperatures to the low 80s and humid virtually overnight. Much like altitude, running in hot, humid weather is a lot more demanding on the body, especially in the first two to three weeks. You have to work harder to cool yourself, and often you'll notice heavier breathing and a higher heart rates, even at your normal running pace. Worse, in humid weather, sweat doesn't evaporate efficiently and your body really struggles to cool itself.
But you will acclimate given time. The easiest way to train is to run by your effort (how you feel and your breathing) and use your watch as a secondary source of information. In other words, when you head for your next run, instead of running at your normal 10:00 pace, run at the effort that feels like your normal 10-minute pace. It will be much slower, but you'll get in a solid workout rather than a crawl to the finish. It will be less taxing on your system, allowing your to recover faster and train sooner.
The key is to run at an effort that keeps your core temperature below the overheating point. You can do this by slowing your pace. If that doesn't work, weave in short walking intervals every few minutes. The idea is to avoid building up heat in your body and crossing the point of no return. It's a little like driving a car through the heat of desert in July. In order to avoid overheating, runners need to maintain an effort that keeps them under the red line. As you work with the heat, your body will adapt and grow more efficient at cooling itself all summer long.
Running on shaded trails or roads:

Running at cooler times of the day (early morning or after dusk).
below to ask, learn and win.
Run shorter 30-45 minute loops for your long runs and stash a cooler with ice, fresh cold water, and sports drink.
Wear an ice-dana (yes, I just made up this word but it s great way to describe putting ice in a bandana). Keeping your neckline cool will help keep your body cool.
Wear loose-fitting, light colored clothing, sunscreen, and sunglasses. These products will help you run and look cool.
Develop yourHow to Train for Your First Sprint Triathlon.
If you continue to struggle after three to four weeks, consider including some workouts at midday to acclimate. Keep these sessions short and easy. You can also take Hot Yoga to acclimate. Just be cautious with the timing of the hot workouts as they take more out of you physically and require more recovery time.
Pay attention to your body's stress signals and if you feel dizzy, light-headed, or experience cramping, stop running and seek shade. Try to find a way to cool yourself quickly.
Be flexible with the goal of your workout. Tomorrow may be a tempo run on paper, but the heat may get in the way of that. Modify, switch up the days, and, if needed, train earlier or inside on extreme weather and ozone alert days. Harsh summer conditions are much like that of a winter storm: they increase the risk of undue stress on the body and decrease the quality of the workout.