by Kevin Gault
When springtime rolls around, athletes and other active people with type 1 diabetes (T1D) have to do more than buy new running shoes, repair a bike, or search for a baseball glove in the basement. Many athletes with T1D agree that there are important considerations about managing the disease during strenuous activity. Exercise burns glucose, so it’s no surprise that hypoglycemia is a major concern. In fact, it has been reported as the number-one reason that more people with T1D do not exercise on a regular basis. And what roles do diet, stress, hormones, and other factors play?
Someone very familiar with exercise and T1D is Brian MacCallum, 42, a production manager in broadcast television in New York City who was diagnosed with T1D at age six. Brian completed his first marathon at age 33, and has since completed 10 more. If that weren’t impressive enough, he also completed the 2011 Ironman World Championship triathlon (photo, right). Early on in his training, Brian learned an important lesson—the hard way—about exercise and blood-sugar control. In 2006, after a 22-mile afternoon training run, he had dinner with friends and turned in for the night. The next thing Brian remembers is waking up to paramedics giving him glucose—his wife had called 911 after Brian’s blood sugar plummeted to a dangerously low level.
“That incident taught me to look at the bigger picture, not just at the specific time that I’m training,” says Brian. “You have to plan for the time after that. This is very important because low blood-sugar levels can occur hours after exercise. Long before you do any sort of exercise, look at your entire day and think long-term. What will happen with my body before I do the activity, during the activity, and after? Will I adjust my insulin dose to keep from going low? Will I adjust my food intake? What is my plan for after the activity to keep my blood-sugar level on an even keel?”
Science gives similar advice. “One of the first things to consider is adjusting your insulin dose before you exercise,” says Hirofumi Tanaka, Ph.D., associate professor of kinesiology and health education at the University of Texas, Austin. “Exercise makes your muscle tissue more sensitive to insulin, which can make your blood-sugar level drop too low. Furthermore, your muscles may remain insulin sensitive for 24 to 48 hours after an activity. So if you’re new to exercising, you should monitor your blood-glucose levels well into the recovery phase—every two hours after finishing exercise.”
Blood-sugar patterns can be tricky to predict, but it gets a lot easier if you write it all down, says Josh Maio. A writer and editor, Josh, 34, has coached kids’ soccer and basketball and now trains marathon runners—he has coached the JDRF team in the New York City Marathon for the past two years (photo, right: the JDRF 2011 team). “There are advantages to taking a scientific approach to managing type 1 diabetes when exercising, and that includes keeping a training journal,” says Josh. “If you record your blood-sugar level before, during, and after an activity, you can chart your high and low blood-sugar levels alongside your nutrition and hydration patterns, and you can start to see what works best for you.”
“It is important to remember that despite having T1D, you are an athlete, and you need fuel in order to perform,” says Joe Largay, a physician assistant and certified diabetes educator at the University of North Carolina Diabetes Care Center. If your glucose is too low or high, your muscles cannot perform as well. “During endurance events lasting longer than an hour, it may be helpful to consume extra carbohydrates at regular intervals to reduce the chance of glycogen depletion and resulting hypoglycemia later in the event. Athletes need 30 to 50 grams of carbohydrates per hour to maintain energy levels.“
Hydration also plays an important role in energy levels, and it can be difficult for people with T1D who do not want to consume a lot of sugar to stay hydrated. Fluids with different carbohydrate levels can help. Some people carry one bottle of water and one bottle of low- or high-carbohydrate sports drink to give themselves a choice, depending on which way their glucose is trending. Don’t forget the electrolytes you need to replace because of sweating. You can even get electrolyte tablets to drop in your water bottle—and skip the extra carbohydrates.
Whether you’re a morning person or a night owl, the time of day that you exercise can make a difference as well. “Your blood-sugar level is different when you wake up in the morning compared to later in the day, and you might also have to factor in a high-stress job or less-than-optimal nutrition during a hectic day,” says Josh. “It’s good practice to know your blood-sugar level about one hour before you exercise. That way, if you need insulin or food, you have enough time for either to get into your system by the time you start exercising.”
Hormone levels can also affect how your glucose level changes in response to activity. “Typically, counter-regulatory hormones—including glucagon, adrenaline, and cortisol, among others—are highest in the mornings and lower in the afternoons,” says Mr. Largay. “Some people thus experience a less dramatic lowering of their blood glucose during, for example, a morning run than an afternoon run.” Women and girls sometimes experience more dramatic changes than men. And some people actually experience a rise in glucose when exercising. “It is fairly well known that resistance exercise such as weight training usually raises or has a neutral effect on glucose levels, while aerobic activity such as running, cycling, or swimming lowers it,” says Mr. Largay.
Simply put, everyone’s body responds differently—just ask Karen Sayre. A business analyst in Jacksonville, FL, Karen plays competitive tennis, sometimes for five hours a day (photo, right). Instead of fending off low blood sugar like most athletes with T1D, however, Karen fends off high blood sugar. “I suppose it’s because of the adrenalin when I play a fast-paced, challenging tennis match,” Karen says. “To counteract the rise in my blood sugars, I actually increase my basal rate for a portion of the match time, then decrease it for several hours after the match. I keep my insulin pump on when I play, tucked in the back of my waistband where it’s least intrusive. Since tennis matches can go on for a long time, I keep a mini testing meter in my bag.”
For younger athletes, parents and coaches are often key to keeping blood sugar in check. Ethan Toone, an 11-year-old from Murfreesboro, TN, was diagnosed with T1D at age nine. He wrestles at a local club, taking after his father who also wrestled when he was young. Ethan (photo, right: boy in blue), who uses an insulin pump, strives for tighter control during wrestling season. “I test my blood-sugar level before and after every match. I take off my pump before I start a match, and if my blood-sugar level is high when I’m done, I put the pump back on until the next match,” he says. And Ethan’s parents are paying just as close attention. Wrestling events can last many hours, so on match days, his mother, Andrea, plans far ahead. She packs Ethan’s meals and snacks for the entire day, and includes carbohydrate-rich foods to raise his blood-sugar level if necessary.
Throughout the day, Ethan’s parents rely on him to let them know when he needs help. “We use hand signals so we don’t draw too much attention to ourselves,” says Andrea. “If Ethan gives us a thumbs down, it’s not because he’s having a bad match, it’s because he’s got a low blood-sugar level. He then shows us the number with hand signals. It’s a good way of communicating in hectic situations.”
Shelby Pate of Columbia, TN, is the mother of 10-year-old softball player Haddie (photo, right), who was diagnosed with T1D when she was five. She takes as much action as possible before a game to keep Haddie’s blood-sugar level in check and keep her on the field. “We start checking Haddie’s sugars about an hour before the game and try to get the level where we want it,” says Shelby. “We usually like to start the game a bit high—a perfect starting blood sugar for her is about 175—because we know it’s going to come down during a game. If she starts a game lower, we lower the basal rate on her pump and have her drink some low-carbohydrate Gatorade. If her sugars are high, we adjust her insulin pump to bring them down. It’s a lot easier if you tackle these things before a game rather than battling high or low blood sugars during a game.”
Of course, curve balls happen. In those cases, Haddie’s coach gets into the act. “He helps me out a lot,” Haddie says. “I give him a ‘thumbs down’ if I feel low or a ‘thumbs up’ if I feel high. Then he calls a timeout and takes me out of the game so I can check my blood sugar and take care of it,” Haddie says. “As soon as I’m ready, my coach puts me back in the game.”
If you’re like most people, that last mile or that final push up the hill can be the most challenging, and many people with T1D have difficulty distinguishing between fatigued muscles and hypoglycemia. “Many of the symptoms you experience during exercise, such as fast heart beat, sweating, and fatigue can mimic the symptoms of hypoglycemia,” says Mr. Largay. Following a routine of monitoring your glucose and keeping good records of insulin and food intake can help you begin to notice patterns, and to be better prepared for the big event. “Of course, with all the variables in play that may affect your glucose on any given day, it is important to be prepared for anything.”
And after all this effort figuring out what works best for you? Marathon runners have an old saying—nothing new on race day. Stick to familiar foods and drinks, so that you know what glucose response to expect. If you have never eaten pancakes before an event before, don’t start now. (But dig in on another day!)