Pump Therapy for Athletes with Diabetes
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.
The ability to set temporary basal rates is also applicable to athletic events that actually raise blood sugar levels or post-exercise blood sugar spikes. In this case, an athlete can simply set a temporary basal rate that is 150% of normal rates, or even 200% of normal rates. I used this feature frequently after races when I expected a spike in blood sugar.
In addition, using a pump offers the opportunity to use a continuous glucose monitoring system (CGM), an exciting new piece of diabetes technology. Many of the larger insulin pump companies now offer systems that integrate the insulin pump and the CGM sensor into one device. Using a CGM offers the diabetic athlete serious benefits, most importantly the ability to monitor blood sugar levels closely during training without having to stop and do a finger stick. The CGM can also notify its user of trends, such as rapidly increasing or decreasing blood sugar levels, allowing for preventative action and the avoidance of severe situations.
Overall, the pump offers a number of obvious advantages to athletes with diabetes. However, the greatest advantage may not be found in one particular feature of the pump. In my opinion, the pump is most valuable to me because of the data that it offers. My pump stores all of the information regarding my basal rates, my daily totals, my bolus history, and temporary bolus patterns. When I relate this information to my training schedule, performance, nutrition, and blood sugar logs, I can often see patterns that may be helping or hurting my athletic performance. I have not only the tools, but also the information, to make small adjustments to my insulin regime in order to optimize how I feel. The ability to troubleshoot on a daily basis has allowed me to dial in a routine that allows me to feel good and be safe when I exercise.
Yet, the pump is not perfect, and there are several advantages of using a pump that are particularly noteworthy to athletes. An individual using a pump has to wear an infusion site, which includes a small subcutaneous catheter, all of the time. This infusion site, while usually painless, can still get sore, especially when it is jostled. For athletes in contact sports, the infusion site may be particularly sensitive and susceptible to coming out. For athletes involved in water sports, the adhesive of the infusion site may be weakened by prolonged hours in water. In this case, it may be necessary to use extra adhesives to prolong the life of the set.
While many athletes will choose to disconnect the pump altogether during events and training, there are some cases where this may not be possible or ideal. If the pump is not removed, it is essential that it stays in a secure place on the body where it will not fall, possibly damaging the pump or pulling the infusion set. The cord must also be positioned in such a way to avoid a kink, which can interfere with normal insulin delivery. For athletes that are training or competing outside, the temperature of the pump is also crucial. The biological activity of insulin is reduced if the insulin is subjected to extremely high or low temperatures, so the pump may have to be cooled or insulated specially to protect against the elements.
The pump is also associated with a greater amount of equipment than syringe therapy, and it may be necessary to carry extra infusion sets, reservoirs, and backup syringes. Particularly for endurance athletes who may be training at remote locations with limited means of carrying supplies, the extra equipment may be a turnoff.
The decision to use a pump is a different decision for each individual; this holds true for athletes as well. There are a number of factors related to the sport itself, such as intensity, duration, location, conditions, and contact level. In addition, the individual athlete needs to consider the accessibility to set site, the logistics of carrying the pump and other supplies, and the implications of wearing an infusion set and being connected to a machine. There is no right or wrong answer, and athletes with diabetes continue to be successful everyday with or without the pump. In my personal experience, I have found the advantages to outweigh the disadvantages, and I believe that using a pump, and analyzing the unique data that is offers me, allows me to be a better athlete. While it is not perfect, the access to precise information about my insulin history and the ability to make small adjustments has allowed me to optimize my athletic routine in a way that is not possible with injection therapy.