I'm not currently on Lantus, but when I used to be on it and doing long activities, I would often take 50-75% depending on the upcoming activity. If you do 2hr rides often, than the impact won't be nearly as much. If this is a one time thing, than you'll want to make a pretty big adjustment.
One thing that I found helpful was splitting up the doses. Though Lantus does last about 24 hours, you can take it multiple times in a day. It's common for some to take 2 doses in a day, so that you could still have a regular "basal" at night, but a lower amount during the day (or however you time the doses).
Once I get into cycling all the time, my basals don't need much adjustment. I guess my body got used to activity better. I do still adjust during exercise, eat a bit more, and don't need as much insulin for meals afterwards, but I no longer need to reduce basals for long periods of time after being active.
Thanks Andy. Appreciate the history. I'm currently splitting my Lantus daily quantity into two injections; one at 6 AM, the other at 6 PM (breakfast and dinner essentially). That would allow me to reduce the evening dose if the day was extra-active to possibly help prevent a night-time low. During the long ride, I'll probably compensate by taking in more carbs as the ride lengthens. Hate to be just chasing lows with food, but only if the activity is well-planned and executed would it be reasonable to adjust the dose of Lantus downward in advance of the ride. My problems with lows usually occur hours after an extended activity than during it; unless it's a 5+ hour event of some kind.
I was on the Animas pump until recently when due to a crack in the battery receptacle and stripped cap threads, I had to abandon it for Lantus. Weird, but my control has been much flatter since going back on Lantus. I had frequent infusion site absorption rate variability that was causing way too much unpredictability on the pump. I'm going to stay on Lantus for the time being at least, but may go back to pumping if I have trouble making adjustments for more extreme physical activity.
I do frequent long rides, including a few centuries. After experimenting a bit I looked for advice from diabetic triathletes and their coaches. Also from the Diabetes Exercise and Sports Assoc. (DESA). I summarized the "formula" prescribed to me here.
You may find that endurance athletes use a pump almost exclusively due to it's assistance in varying basal rates. Most importantly is it's capacity to set reduced rates and gradually bring them up post event.
New to the site and LADA, I realize this was posted a while ago but I too am not pumping and currently can see no need for it as I use a single dose of Lantus in the A.M. and am able to maintain excellent BG with a low carb diet and regular excersize (biking, swimming, weights and occasional runs). Admittedly my road biking has thus far been under 2 hrs/session and I am anticipating some issues when I/if I up this in the future. Would be interested in hearing how you are managing the longer rides.
Hey Bob- Just saw this, so I apologize for not replying sooner. I had some good experience this summer on a 3-day fund-raiser bike tour up in Summit County, CO. The ride consisted of: day1, 56 miles with a top of 10,600 feet and about 4000 feet of climbing; day2, 85 miles in 6 hours and again about 4000 feet climbing; day3 46 miles with about 3000 feet climb. My normal lantus daily is 8 units. I cut it to 4 for the riding days. Normal bolus assumption is a novolog/carb ratio of 1unit/20grams. Operated instead with a 1unit/30gram rule. This worked out pretty well, but I still had one overnight low in the 40 mg/dl range that I had to slam some fruit juice to correct in the wee hours of the morning after that 85 mile day. It's always a challenge, but for me, lantus is still preferable to the disastrous absorption variablity of the pump infusion sites.
Thanks for the tips Tom. I am hoping to try a longer bike ride this coming year. If I do, I'll let you know how it goes. Also when riding, do you bolus for each time you nutrition up and how often do you actually check your BG? I suppose this requires a bit more stopping than the average cyclist.
Bob- I usually check at the rest stops. Since I'm not racing, I get off the bike and test it. When riding at an average 17-18 mph pace, I usually eat about 30 grams of carb per hour of riding, and at that rate, there is no need for me to bolus. If (when) I start seeing the BG readings drop, I eat more. That probably says the lantus could be reduced even more than the 50% I indicated in the previous post.
Best to you!
Tom, Thanks again for the info but this raises a further question...If you are not bolusing during the ride, how are you replacing your glycogen stores? My understanding is that without any additional insulin beyond the basal rate (i.e. your Lantus) your carbs eaten (converted to glucose) along the way will not go into the cells to replace glycogen lost from the activity. This should require replacement somewhere between 1-2 hrs after starting the ride. Maybe I am just over thinking this or maybe at a non-race pace this is just a non-issue.
Who knows. I keep basal at -80% usually, so that means there is some insulin still kicking. Similar with this situation with 4u Lantus instead of 8 - you still have something acting there. Generally I eat if I'm under 120 or so on the CGM, to try to keep it level. While riding long days, I don't eat big meals, but keep chipping away at my food all day and drinking plenty too. My longest ride was 158 miles this year, and my bgs were just fine throughout the day. I typically bring clif bars, Newman cookies (similar to oreos and loaded with carbs), and grab some salty treats on the way like slim jims and peanuts. Then I pig out on protein when I get home: cheeses, nuts, chocolate milk. Apparently that works, because I then commute throughout the week and still have energy to do another century the next weekend.