Guest Blog Post By: Matthew Schoenherr

This past weekend I raced in my first triathlon of the summer.  My time was average but the most exciting part was the lack of bonking!  (For those not familiar with the term, it means running out of energy.)  I cannot remember ever finishing a triathlon without bonking on the run.

There can be a lot of factors that could lead to bonking.  So what did I do differently?

Did I have better hydration?

I had one 24 oz bottle of water mixed with 3 scoops of GU electrolyte brew, totaling 39g CHO. That’s less than normal.

Did I Over-train for previous races?

No, I am currently in the midst of the hardest part of my training program.   I did not taper for this event.  I am as close as you can get to over-training.

Did I have more consistent training?

Well yes, but that’s not the point.


I avoided HYPOglycemia, not only during the race, but for the entire month of training.  I have had less than 2 lows per week, and was only below 70mg/dL for less than 30 minutes this month according to my CGM data.  When your blood sugar is low, the brain steals glycogen from your muscles and liver.  And when that happens, there is less available for your race.

I also avoided HYPERglycemia.  In the past races my blood sugar would skyrocket the morning of the race.  It actually did that twice:  once while eating breakfast, and once right before I entered the water.  To avoid this, I made sure I took insulin for my breakfast, in-full, three hours before race time, then waited 20 minutes to eat.  I also had 40g of fast-acting carb 20 minutes before entering the water.  This took care of any extra active insulin and compensated for early-exercise insulin sensitivity.

The acute aquaphobia-induced hyperglycemia was most definitely pre-race adrenaline mixed with hyperglycemia earlier in the morning.  There are different ways to avoid this:  breathing exercises, music, and sports psychologists are a few examples.  Personally, all of these create more stress for me.  My cure:  racing with friends.  Nothing calms the pre-race nerves like having a few laughs with your friends right before you jump in.   Also, avoiding hyperglycemia kept me well hydrated.

THE SECRET TO SUCCESS with diabetes is KEEPING RECORDS and learning from them.  If I took better records four years ago, I would have had more successful races ever since.  Everyone’s body is different, so start recording and find out what works for you!

Keeping records of your diabetes

Here is my race day CGM data.  I did have a sharp rise in glucose after finishing (not shown).  Find out why and how to anticipate and prevent this by making an appointment at Integrated Diabetes, where I just completed a 7-week internship under the tutelage of Gary Scheiner, Lisa Foster-McNulty and Jennifer Smith – truly an amazing team!

Follow me on my blog site at and twitter @activediabetes. To see what adjustments I make for the taper phase of my workout program and for my “big race” in September, the Nation’s Triathlon in Washington, DC.

Blogmasters’s note:  Matthew Schoenherr is a graduate student studying exercise physiology at George Washington University in Washington, DC.  He has had type-1 diabetes since age 4, and uses a pump and CGM.  Matt hopes to focus on diabetes and athletics after he graduates this coming spring.