I always wanted to get into running and my New Year's resolution was to be able to run 30 minutes straight, four times a week. I've kept it up until the Summer sun and heat got the best of me. Now I can barely do 15 minutes and I'm exhausted. I tried pushing myself, thinking it'd just take some getting used to, but now during my runs I get headaches, stomach cramps, sweat uncontrollably, and a few times felt dizzy and nauseous. I don't want to give up on running outside since I'm training for a half-marathon this Fall. I also don't have access to a treadmill in an air-conditioned gym. Any tips?
Being too hot to exercise the way you want to is so frustrating. I have some suggestions though so
Summer is generally a hot time of year, but certain times of the day are hotter than others. Try to do your runs early in the morning or late in the evening when the sun is out of the sky. Stick to shady places like the woods, or breezy areas such as near the ocean or a lake. Make sure you hydrate before you head out and bring water with you to drink and pour on your body to help cool you off.
Wear a heart rate monitor to keep track of your heart rate. When exercising in the heat, your heart rate will rise in order to send more of your blood supply to your skin to cool it down. A heart rate monitor will allow you to keep track of the intensity of your workouts. This means you'll probably have to run at a slower pace, or even walk, which just means your normal run will take longer. If you don't want to compromise your pace, then break up your workouts. Do 15 minutes in the morning and 15 minutes at night. Or you can slowly train your body to acclimate to exercising in the heat. Gradually increase the duration of your runs until you're able to go for 30 minutes.
I must say that the most important thing to consider when running in heat and humidity is to listen to your body and not overdo it. Some of the symptoms you described above sound like they could turn into heat exhaustion, which means your runs will be doing more harm than good. In that case, think about using this time of year to cross train with cooler cardio activities such as swimming, kayaking, and water aerobics.