For any person with diabetes, deciding to go on a pump is a big decision that involves a careful analysis of the pros and cons of both pump and injection therapy. Many endocrinologists encourage diabetics of nearly every age to consider a pump for optimized glucose control and increased flexibility. However, it is important for each individual to assess whether a pump is the right options for them. For diabetic athletes, the decision is particularly important, as the pump provides both distinct advantages and disadvantages in terms of athletic training and competition.
The pump system includes an infusion site, tubing, an insulin reservoir, and the pump itself. Pump users program their insulin in terms of a basal component and a bolus component. The basal rate is an hourly “background” rate of steady insulin; it can vary throughout the day and be adjusted to one tenth of a unit of insulin per hour. The pump delivers the basal rate consistently without any input from the pumper. By contrast, the bolus component refers to the amounts of insulin that are manually programmed and delivered. These include meal-time boluses and correction boluses. The dosages are calculated based on a carbohydrate and correction ratio that can be determined with the help of an endocrinologist. The advantages of the pump are well-known. Pump-wearers do not have to do individual insulin injections, take insulin at any time with just the push of a button, and have much more flexibility in terms of sleeping and meal schedules. The pump delivers more accurate insulin dosages than a syringe and eliminates some of the unpredictability associated with long-acting insulin.
One feature of the pump that is particularly important for athletes is the “suspend” feature- pumpers can simple suspend the pump before exercise, stopping the delivery of all insulin, to avoid exercise lows and the obligation to consume carbs before a workout. As long as the pump is connected right after the workout, this strategy is effective in eliminating lows that would be unavoidable with a fixed basal rate from an injection of long-lasting insulin.
Yet, the pump offers some more subtle benefits for athletes. While the ability to suspend all insulin deliveries is useful, there are cases when this may not be ideal. For example, endurance athletes may be training for hours at a time; this duration of time is too long to omit insulin all together. While it is not a good idea to disconnect the pump entirely for these times, the basal rates can still be decreased in order to counteract the blood sugar lowering effects of exercise while maintaining safe levels of insulin in the body. I found that for training sessions of one hour or longer, a temporary basal rate of 40% of my normal basal rate prevented both exercise lows and illness associated with not enough insulin.
