Yesterday I had an opportunity to take my first decently long ride of the year. So far I've only been out a couple of other times, with the longest ride being only about 12 miles, and that ride was cut short due to it starting to sleet.
I am Type II diabetic. I had been having trouble controlling my glucose levels, and along with diet, the long rides were helping. I had been taking 250mg of Glucovance 3 times per day. About a month ago, my doctor started me on a new prescription, adding a new drug called Januvia. The improvements have been dramatic!
Anyway, yesterday I started out intending to ride about 20 miles. I was feeling so good, however, that I decided to do 30 instead, with the simple expedient of riding 15 miles according to my Astrale 8, then turning around and riding back home.
When I got to my turnaround point I tested my glucose and it was 85. So far so good, as I carried a light snack and was intending to eat it then. For a snack I had a package of peanut butter and cheese crackers, which amounted to about two carbs. I thought, though, that with 15 more miles to go to get home, I better add something. A had a granola breakfast bar in my handlebar bag that was worth about one carb, so I ate that as well. I then started back.
After a few miles I was noticing a headache and some general tiredness and a touch of dizziness. I stopped for a rest and tested again, and was down to an 80. With about 10 or 12 miles to go, this wasn't looking good! I dug around in my handlebar bag and found three pieces of hard candy that I carry as a kind of emergency picker-upper. I rationed those three pieces of candy for the remainder of the trip, and did finally make it home without crashing (in both sense of the word).
Pre-Januvia I would not have had a problem with the consumables that I had with me. As a matter of fact, the peanut butter cheese crackers alone would have been sufficient.
So, the moral of the story is: After a med change, be very, very careful and monitor your condition during exercise, and be sure to carry enough supplies to carry you through any eventuality.