Type 1 Diabetes and Ultra Endurance Sport – Why I take Lantus in the Morning instead of the Evening

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I know that many of my readers are probably using an insulin pump – but globally, only 1 in 1000 people use a pump. Statistics for the UK show that only 6% of adults were using an insulin pump in 2013¹. Therefore, I believe that discussing Lantus and MDI (Multiple Daily Injections) still has a lot of relevance.

Oddly, Lantus is only FDA approved for evening injections – and the timing of injections is what I want to discuss in this post. In my experimentation, I found that I have the best glycemic control when taking Lantus first thing in the morning, or when splitting the dose. The hardest to control was actually when I was using the evening regime!

I’ve experimented with 3 dosing schedules for Lantus – Evening, split dose (morning and evening), and finally the one I have settled with: Morning only. I believe that morning dosing makes much more sense for me due to highly variable activity levels and schedules. I think the split dose would also be very good – but I find it a little harder to be consistent in terms of timing.

Why would I take Lantus in the morning?

• Occasionally, a Lantus injection can be botched². I believe it is much better to get a potentially dangerous surprise during the day when you can correct with glucose tablets than to find yourself shaking and sweating with your heart pounding at night.
• For most people, Lantus lasts between 18 and 24 hours. For me, it seems to work about 21 hours. When I was taking it in the evening, I would find myself having to inject Novolog or Humalog to cover those 3 hours before my next injection. The time of the day that you need the least insulin (assuming you don’t have the dawn phenomenon³) is first thing in the morning when you’ve been fasting since the previous night’s dinner. Therefore, it makes sense to have your insulin level slightly reduced at that time of day. For me, the insulin is wearing off as I’m entering the latest hours of my post-dinner fast.
• As an athlete, my insulin needs can vary dramatically from day to day. For example, some days, I’ll ride my bike for 21 hours⁴. Other days, I may be resting and recovering from such efforts. During that time I can need a lot more insulin. Rather than try and predict the level of activity the night before the upcoming day, I like to measure my morning blood glucose, using it to make an evaluation on the previous day’s dosage, and then try and make an estimate of what kind of exercise I’ll be doing that same day. I’ll often combine information from the previous day with my upcoming day to try and make an educated guess about how much Lantus I need. As a rough estimate, I’ll use 24-30U Lantus when I’ve been working in front of the computer (i.e. not exercising) for consecutive days. I’ll use 12-15U when I’m exercising at endurance pace for between 2-3 hours in one day and eating the Dr. Bernstein Diet of 30g carb per day. This same dosage seems to also work well for more moderately intense rides that last 1-2 hours. I’ll reduce to 7-9U if I’m doing all-day bike riding at an easy pace and eating low carb. I’ll reduce to 1-4U if I’m fasting (or fast mimicking) for consecutive days.
• For some people, Lantus has a micro-peak after 6 hours. Since I usually inject around 6-7am, this means that for me, the micro peak occurs around 12-1pm – just in time for lunch to help out with lunch dosing. I find that it is much better to have the micro peak happening during a typical feeding time instead of during the night when I’m asleep causing an uncomfortable low. Although I have rarely noticed the micro peak, this is another argument that stacks the cards in favor of the morning dose.

Making the Switch

Transitioning between dosage regimes is quite challenging, and a bit of impatience led me to do it too quickly with bad results. For example, in switching from morning to night, I should have followed a schedule that went like this (assuming I was on a steady 15U per day):
Day 1: 0U AM, 15U PM
Day 2: 1U AM, 14U PM
Day 3: 2U AM, 13U PM
Day 4: 3U AM, 12U PM….

You get the idea. This would have taken 16 days to get the full switch – but I did it in about 6 days (and suffered the consequences of unpredictable hypoglycemia on some bike rides). The problem with changing too quickly is that you get insulin stacking – which means you have two injections overlapping at the same time. It is ill advised to try and switch from PM dosing to AM dosing any faster than the schedule above – and I’m not advising anything. Remember, this page is not medical advice as stated above; I’m just recounting my own experience – readers should consult appropriate health professionals on any matter relating to their health and well-being.

Why not just use a pump?

One advantage of an insulin pump is that you can fine tune your basal insulin throughout the day. Theoretically, this can lead to improved glycemic control. The pump should really help athletes and people who jump between big exercise days and rest days. I’ve written a post about this topic which I will publish soon.

References & Footnotes

1. Insulin Pumps, Diabetes.co.uk https://www.diabetes.co.uk/insulin/Insulin-pumps.html
2. 
   Rapid Absorption after injecting Lantus By SB_Krista, 2016 https://www.diabetesforums.com/forums/topic/78516-rapid-absorption-after-injecting-lantus/
3. Dawn phenomenon From Wikipedia, the free encyclopedia https://en.wikipedia.org/wiki/Dawn_phenomenon
4. 06/23/2017 GDMBR Last Day! by Brian Lucido, 2017 https://www.strava.com/activities/1051923353