Cycling and dropping BG

I decided to start cycling again after I got my Dexcom. I thought I would be able to control my BG while riding now that I have this device. Yesterday I went out for a 30 minute ride at a steady pace. I had an omelet and waffle for breakfast; which was around 30 carbs. I bolused for the carbs and did not reduce the basal rate. When I started my ride my BG was at 189. 20 minutes into the ride I was at 107. I had 15 grams of carbs while I was riding. When I got back to the house I was at 82.

How do you prep for a bike ride to keep your BG high enough so you can ride for longer periods of time? Any advice would be greatly appreciated; because I am truly confused about what to try next.

Cycling lowers my BG very fast and it sounds like you are the same. A lot of it will be trial and error. Variables are when you ride, how hard you ride, how long you ride, when you last ate and the temperature.

I often ride after dinner. I will eat maybe a 45 g dinner and dose for for 25 g (20 grams less). I will start riding about 30-45 minutes after dinner. This often works pretty well for 30 minute rides at a decent pace. I have not perfected longer rides, but my best plan is to add a temp basal to the mix. I suspect an 80% temp basal for about 1 hour and starting 1 to 1.5 hours before exercise would be a good start.

I know that pumping insulin had a chart in one of the last chapters that discuses how sternuous the exercise is, how long you will be exercising and the ways Walsh recomends to cut your insulin dosing. It is a decent starting point as well.

Of course bring lots of carbs and test often.

Would drinking Gatorade help with the carb intake or would that push my BG to high?

It could. Some diabetics use that strategy well and can time their consumption well, especially runners. I have not had much success.

I also want to cut insulin to promote weight loss as appossed to eating energy to fuel your workout.

Today I cut my basal rate to 50% an hour before I rode. I ate a 17 gram protein bar just before I started to ride with a BG at 131. After I began riding I ate a couple of peanut butter crackers a total of 15 grams. Then the downward arrow started on my CGM; So then I started eating everyones favorite; glucose tablets. One every 5 minutes. It kept my BG stable till the end of my ride. My BG finished up at 92 and I consumed 62 carbs for an hour long bike ride. This is the first hour long ride I have done in over 20 years. My cardio sucks and legs are fried but other than that I feel pretty good about this.

If there is anything I should have done different; I welcome the advice.

Watch the next 24-48 hours as well. The exercise will improve your insulin sensitivity even after you stop exercising, especially when you are just starting back at an activity like this. You may find yourself having to adjust your basal rates and I:C ratios overall as your insulin sensitivity increases.

If your BG stayed between 92 and 131 while exercising then you are doing pretty well.

How long before exercise and for how long did you run a temp basal of 50%? “Pumping insulin” recomends cutting them about an hour before exercise and running it close to the completion of exercise. A 50% reduction is large. Monitor your BG post-exercise and see if you get a spike as it may be too much. Also, be concerned about lows for the next 24 hours if you exercised that hard. I often lower my basals overnight if I over do it to avoid a hypo.

I don’t know what else I can tell you? Exercise metabolism is very individual and you will likely have to experiment. As I mentioned earlier, I try to lower my insulin as much as possible to get the most weight loss benefit (insteady of feeding the exercise with tabs). I often still eat 15-20 carbs per ride, but it could easily be more.

Scroll down towards the bottom of the page on this link and it shows “Pumping Insulin”'s exercise chart I mentioned that suggests basal reductions (hope the link works):

I started spiking a little while after the ride; so I gave myself a bolus and it started coming down into normal range. Right now I'm holding steady at 120.

I started the reduced basal an hour before and kept it reduced for an hour. I guess as I want to start riding longer I will need to keep it reduced longer. As I get back in shape should the use of less carbs happen because of getting more efficient.

Will exercising help with DP?

Thanks for your replies.

I agree that cutting bolus back if you bolus before exercise is important. I usually try to have all the IOB gone before I blast off, if it's more than 1/2 hour or so. It can be quite challenging as it involves slotting aside extra time to get ready to run. I really prefer running/ biking after work but with chores, family, etc. AM makes sense. Plus I've always found that I can run off DP pretty safely. Several years ago, before I got my pump, I'd wake up and, if I was high (most of the time...) I'd bolus (R, not quite as fast...) and walk a mile and a half or so.

To add about the chart (I think that might be from "Think Like a Pancreas"?), it also is a guideline (with the provision that you test and see how it works...) to reduce boluses. If you do moderate exercise for the period of time it suggests, you cut the bolus by 1/3 to 2/3, depending on how hard you're pushing it. I've bolused during longer runs, to cover Gu packets or other snacks I've run across, using their 1/3 the dose formula for long duration/ high intensity, and it seems to work well. I'm not entirely sure I'm at high intensity as I'm not particularly fast, kind of in the middle of the pack for my age group so for a 1/2 marathon, it takes about 2 hours. I've only done one marathon (+ bunches of training runs, w/ our group...) so that's a much smaller sample size but I haven't had too many BG issues running recently.

I use Gatorade for running (with an Amphipod belt) and have a couple of bottle racks on my bike. I've used the powdered GA for a while as if you have 2x racks is that you can mix some high octane, w/ like 30-40G/ serving and some lower octane, maybe 10-12G, to use for "balancing" fuel. These days, I usually opt for "regular" as I've gotten to where I can pretty reliably have a shot of it every 3 miles or so and end up sort of where I started?

I am not familiar with Gu packets or GA. I was looking at the bottles of gatorade and it only has 21 carbs per 12 ounces. At that rate I would had needed to drink around 24 oz to keep my BG up. I think tomorrow I am going to reduce my basal rate to 70% and see what happens.

When I started my ride yesterday my Dexcom had my BG as steady. Should I wait before I start riding for the arrow to be going up. Seems like I read this somewhere and it makes sence.

If you don't have IOB when you start will that help with not needing as many carbs while I exercise?

I think it might be best to think of boluses or basals as percentages. I often exercise with IOB, but it may only be 50% of what I would take if I had not planned activity (i.e. dosing for 25 grams of a 50 gram meal). I think this is pretty similar to setting a temp basal of 50%. The main difference is that you want to time your exercise to try to be when your Post paradianal spike will hit and the effects of the basal reduction will be more gradual.

My nightly DP is sometimes stunted by exercise. If I go really hard then my DP is often noticably diminished. If I only go moderately, then my DP is not really impacted. YMMV.

If you are exercising at a moderate rate, then you will likely need to supplement your exercise with some carbs at some point in time. But, I believe reducing you insulin will limit this and lead to better outcomes from your exercise.

I found a good article on exercising with T1D at JDRF: They interview a few active T1s and they explain how they deal with exercise. I especially like that one of the subjects is Sheri Colberg-Ochs, Ph.D., professor of exercise science at Old Dominion University and a T1 for 44 years.

This is a discussion that I will be following. I am riding my recumbent tricycle for 1hr 2x/week and then going for longer rides 3+hrs on the weekends (or whenever I can fit it in).

I frequently see huge drops in the first hour (down to 50 mg/dl). I usually start with a tempy basal of at least 50% 1 - 2 hours before, but sometimes run @ 0%. Still doing a lot of experimenting.

I am fortunate in my trike setup has a bag on the back that lets me carry 50 glucose tabs, a banana (or two) and a protein bar.

If I go really low during the ride, I usually find myself way too high 2hrs after (250+). I know that if I can reduce the lows that should help reduce the highs later.

Thanks for the link Capin101. I started eating more protein before my rides. That seems to be helping with keeping my BG more level during my ride and I'm not dropping as bad. Since right now I am only riding for an hour only time will tell as I start riding longer. I'm not bolusing for any of the food before I ride and I'm doing a 50% basal reduction an hour before the ride. After the ride my BG starts shooting up within 30 minutes. I started increasing my basal rate 100% for 2 hours after the ride plus a 3 unit bolus. I don't really understand why my BG shoots up after the ride because all during the ride my basal will be at the normal rate.

Hopefully with time this will get easier.