Question from Dayton, Ohio, USA:

I am a competitive swimmer diagnosed with reactive hypoglycemia several years ago, and my doctor suggested I check my blood glucose before races and intermittently throughout the season. It is not uncommon for my readings to be in the 50-80 mg/dl [3.8-4.4 mmol/L] most of the time, which causes headaches and makes it hard to focus in class and swim well. However, lately, I have been noticing that when I get up in the morning, my readings are 130 mg/dl [7.2 mmol/L] and higher much of the time. Sometimes when I feel low, I test and find I am over 170 mg/dl [9.4 mmol/L]. In addition, I have been uncharacteristically thirsty lately. What confuses me further, however, is that usually after I eat, my sugar drops an hour or so later, down to 60 mg/dl [3.3 mmol/L] or so.

I am confused. How this could be happening, given that my body previously never reacted this way to sugar? Should I schedule an appointment with a doctor?