Happy July! Are you planning out your July 4 food already? I’m on the fence between a hot dog and a burger. It’s always a tough call for me!
July also brings with it some of the hottest days of the year for most of us. As a runner, I need to pay particular attention to what the heat does to my body. As a type one diabetic, I need to pay particular attention to what working out in the heat does to my blood glucose.
I have an air conditioner in the room where I work out, but what about summertime runs in the middle of the day or after work? I need to be prepared for the heat and prepared for a drop in blood glucose when the temperature is not what I’m used do. (This is why I was very concerned before my marathon this year that the Florida heat would be a shock to my system that was used to running the distances in my January cold environment—I can run through a lot, but I cannot run when I’m low, and my first few runs in the summer heat usually cause me to drop. I was lucky that the freakish cold snap meant I froze but I could keep running!)
I went to a lecture last year by a running expert, Jason Karp Ph.D. I like what he has to say and most of my experiences mirror his information amazingly well. (I also get a kick out of his corny jokes.) I’m summarizing his July newsletter here that discusses the main concerns for summertime workouts:
Running in the heat presents a number of thermal and cardiovascular challenges. The two most important things you can do to prepare for your summer outdoor training sessions is hydrate and acclimatize.
HYDRATE
Beginning the workout fully hydrated or even ‘hyper-hydrating’ before a workout can delay dehydration during exercise, maintain exercise performance, and decrease the risk for heat-related illnesses. Pre-exercise fluid intake enhances your ability to control body temperature and increases plasma volume to maintain cardiac output. Drink before you run in the heat so you begin every workout fully hydrated, and continue to drink during workouts longer than one hour. A good indicator of your hydration level is the color of your urine. The lighter the color, the better. The best hydrating drinks are those that contain sodium and glycerol (you can buy glycerol and mix it into your drink).
ACCLIMATIZE
Chronically exposing yourself to a hot and humid environment simulates adaptations that lesson the stress. Cardiovascular adaptations to exercising in the heat (e.g., decreased heart rate, increased plasma volume) are fully complete after 2 weeks, as the increased sweating response catches up to other adaptations. You should take 2 weeks of slowly introducing yourself to the heat to be fully acclimatized and prepared for longer runs. When preparing for high-intensity workouts such as interval training, however, you may not need as long to acclimatize. Research has shown that just four 30- to 45-minute sessions of intermittent exercise in the heat is enough to cause acclimatization and results in an improvement in intermittent running workouts. While exercising in the heat will always present a stress, acclimatization has a moderate prophylactic effect, minimizing the stress and reducing the risk of heat-related illnesses.
I also point out for all of us living with diabetes that the first few workouts of the summer heat are NOT the workouts to push through feelings of exhaustion or low energy. They are NOT the workouts to skip the basal rate reduction or to skip the snack before you start. They are NOT the workouts to add on a couple miles when you don’t have glucose with you. Save those workouts for a few weeks, when you’re used to the heat, you’re properly hydrated, and ready to rock it.
