Do You Need to Worry About Athletes’ Blood Sugar?

 

Blood sugar and monitoring blood sugar spikes using a continuous glucose monitor has been making headlines in the health, fitness, and wellness industries in recent years. But is monitoring blood sugar in healthy young athletes actually necessary, or even useful?

Here, TrueSport Expert Stephanie Miezin, MS, RD, CSSD, the Director of Nutrition for the NWSL team, KC Current, is explaining what blood sugar levels mean for athletes, whether monitoring these levels ever makes sense, and how coaches can spot early warning signs of low blood sugar during training and competition. Also note that this article is not referring to athletes who have Type 1 or Type 2 diabetes. For athletes who are diabetic, blood sugar must be considered and monitored in a different way.

 

Do You Need to Worry About an Athlete's Blood Sugar Levels?

For coaches who only see their athletes during practice, monitoring high and low levels of blood sugar simply isn't an effective use of time. "There is a lot of hype around things like blood sugar spikes and continuous blood sugar tracking, but most of what's out there is just noise,” says Miezin. “A lot of it is marketing and fear-mongering, making people think that things like blood sugar spikes are really bad."

 

What's the Difference Between High and Low Blood Sugar?

Low Blood Sugar: When it comes to blood sugar, low blood sugar is the most likely issue for young athletes. This simply means that the amount of available glucose in the athlete's body has dropped below the healthy range that allows enough glucose to flow to the brain for proper function. "If an athlete has low blood sugar—also referred to as low blood glucose—then a coach will likely notice that athlete exhibiting a low mood, feelings of fatigue, a lack of concentration, and declining performance," she explains. Under-fueling, and sometime exercise, can lower blood sugar and begin to cause these feelings. Low blood sugar, or blood glucose less than 55 mg/dL, is not very common in non-diabetic athletes. If it does occur, it can usually be easily corrected with a carbohydrate-rich snack like crackers or fruit, or beverage like juice or sports drinks. Although not typically dangerous for non-diabetic athletes, low blood glucose does impair both physical and mental performance.

How do athletes avoid low blood sugar? It's simple: "Help your athletes follow typical sport nutrition and timing recommendations," Miezin says. "If they're already following the regular recommendations around the amount of carbohydrates to consume and when, they are going to be inherently addressing this problem of not getting enough energy in the system. As long as they are having enough carbohydrates throughout the day, especially around exercise, then you probably don't need to worry about low blood sugar."

If you do suspect that an athlete is starting to feel that 'bonking' sensation where they suddenly become grumpy or fatigued, give them a small carbohydrate-based snack or drink and let them rest for a few minutes before resuming play.

High Blood Sugar: "High blood sugar is what happens when our blood sugar spikes up," says Miezin. "I think that the word 'spike' is interesting because it sounds inherently bad. But having blood sugar spikes, which we might categorize as a quick rise and fall of blood glucose, is entirely normal. If it goes up relatively high after eating a carbohydrate-heavy meal or snack, and then comes down relatively fast, that essentially means your body's working the way that it should. There really isn't good reason to be concerned about blood glucose spikes in an otherwise healthy person that doesn't have diabetes."

"When your blood sugar spikes and then drops, that indicates that the carbohydrates got into your bloodstream, your body recognized that the carbohydrates were there, and quickly moved them from blood into tissues like muscle or the liver," she adds. "And different foods can affect people differently. Some foods that are going to cause blood glucose to rise higher in one athlete may have a much lesser effect in another athlete. The combination of food and the speed you ate at can also affect whether your blood sugar spikes, as can your stress levels. And the same food can even result in different effects on blood glucose in the same person from day to day. It's extremely nuanced, which makes it unrealistic for a coach to offer any kind of useful guidance."

High blood sugar levels only become a problem when associated with high HbA1c, which represents the amount of glucose attached to hemoglobin in one's red blood cells. This measurement is a long-term trend and can indicate that an athlete is pre-diabetic. However, this test can only be done in a lab, so as a coach, it's not something you can check for yourself.