Going high and higher during workouts...?

I’m a rower and have been running into the same problems while I’m on the erg and can’t seem to figure it out or fix it and am just looking for some suggestions/help.

I can’t seem to find a happy blood sugar that will allow me to row and complete a workout without going high, or if I’m high and correct, I’ll go higher. For example, I was 157 one day, rowed a hard-all-out 8 minute piece and immediately after, I was over 300. I know adrenaline plays a role, but really? Or for morning practices, I eat before working and I have made it a habit to bolus beforehand and even wait a half hour before eating, but I am still high before I start working out (I usually correct too) and when I check during the work-out, I am even higher.

So if anyone knows of tricks or trips to prevent highs or going higher during work outs, could you please offer me some insight? I’ve tried temporary basals, changing my eating habits, etc. and nothing seems to work.


I need advice too. I’m facing the same dilemmas!

It’s probably a combination of things, but you are on topic w/ the idea of adrenaline. When you are exerting that much effort (for pulling a 5k in a race or on the erg for example), it’s 99.9% likely that you’re going anaerobic. When this happens, your body is not utilizing the normal glucose-burning properties to make ATP (energy for your cells). So any glucose in your blood stream (and in the interstitial space next to your muscles) is not being utilized. Dump adrenaline and cortisol (both side effects of intense exercise) into your system (which both have a tendency to cause insulin resistance) and it is of course not really helping your glucose remain stable–frustrating to say the least!

In my experience with intense anaerobic exercise like that, I have had to forgo eating a meal beforehand (b/c of the increase in insulin resistance from my nerves, on top of the whole anaerobic aspect, on top of the cortisol dump, etc lol). Or if I did eat, it was something lower in carbs. Also for my endurance activities I’d eat/drink supplemental carbs (like gatorade) but in really intense activities (for me a cyclocross race is my intense/anaerobic activity) I can’t consume any of those carbs…I just drink water instead.

You may be able to help minimize this by increasing basal rates. Remember that any change in your basal should be made 60-90 minutes prior to the activity though (b/c the insulin you’re getting now from your pump isn’t the insulin that’s being used now…it’s the insulin that was delivered roughly an hour ago). This increase is of course dependent on the fact that you will be going anaerobic. If you’re just going to do an endurance workout where you’re pulling at 70% of max effort for 20k meters or something (vs. giving 95-100% effort of high intensity for a 5k or less), then you’d likely not want to do the basal increase b/c that would result in a big crash in your BG level.

Also, when I get done w/ a workout of high intensity, I also give a bolus afterward (b/c sometimes the body does not “realize” that the exercise has ended, and so the liver continues to dump cortisol/adrenaline into the blood stream for a short time afterwards). For example I got done with a bike ride on the trainer last night that was only 1 hr and 15 minutes long, and was pretty high intensity intervals. I ended w/ a BG of 78, but I went ahead and bolused 2 full units (which in a “normal” situation my correction factor is nearly 1:40 so that should have basically put me at a BG of 0 lol). However, my BG still rose to 157 about 20 minutes after I had finished working out (I didn’t give enough of a bolus to prevent that post-ride whip).

Wish I could help, I’m having the exact opposite problem…I’ll start with a normal number, even on the high side and I crash, I’ve tried all the tricks you just mentioned, starting out higher, adjusting basal, eating habits…it is a never ending balancing act to, as you say Sara, find a happy sugar place that will allow for safe workouts.

Sara, you do a much more intense kind of exercise than I am doing. I have read many times that a lot of carbs are needed to keep the liver from dumping a load of glucose to compensate for the extra activity under those conditions. I exercise no more than 30 minutes after a meal so the needed carbs are present. I an type 1 and take insulin for those carbs, but I take only half the insulin dosage I would normally use. Otherwise, I would have a hypo. I workout at a gym for about 80 minutes on machines with weights. I test every 20 minutes and eat glucose tablets when needed. I know that if I did the rowing that you are doing it would be wonderful cardio exercise, but I am 71 and cannot handle that.

Our CDE recently checked out a Dexcom for a week to my son mainly so she could see what was happening during hockey practices and games. He plays on two different teams so these highs from nearly daily practices/games are affecting his A1C. TheDexcom receiver has to be within 3-5 foot so we had to rig a special pair of shorts with a velcro enclosure on the pocket. I now know that there are runners belts that could have held it during exercise (even water resistant ones)…

It was really interesting to see how his blood glucose fluctuated during hockey.You could see the low trend and then spikes when he drank gatorade and everything. It took a lot of readings throughout the activity. He was 300 after the game but not as high after the practice. Of course, there is more intensity and adrenaline during the game, especially the one we monitored because it was extremely close.

The CDEs protocol is to eat carbs without insulin within one hour of the activity in order to increase blood glucose to 150 - 200, eat carbs during the activity to maintain blood glucose without reduction to the insulin basal in the pump. The basal is temp’d down for double the activity time right after the activity. (For 1 hour of hockey, we temp basal down for 2 hours after the game). Then, they don’t want him to test until 1 hour after the game (He had dropped from 300 to 147 even with a temp basal running after the game).

This is different than the protocol used by many in the Diabetic Athlete’s Handbook which does suggest temping basal “during” hockey rather than the pre-eating but our CDE feels the carbs before and during exercise will help prevent the severe lows he was having later.These were scary because they were 6 hours out usually in the middle of the night.

The book also includes a page and a half on Rowing suggestions and the regime used by Olympic Rower, Chris Jarvis. He is adjusting basals according to his type of training (warmups vs intense) practiceand having to do units of insulin to correct after rowing practice even though he brings his basal back up to normal 30 minutes before practice is over. Sounds like you are in good company!

Hi Sara – I’m a rower too! I’ve found that rowing workouts are so much harder to plan for than other types of activity, probably due to the mix of aerobic and anaerobic activity that can occur during the same workout. I have had major problems in the past month with my blood sugar rising like crazy during a 2k erg test and interval workouts. I always hesitate to take a bigger bolus before a practice since IOB=lows under any other circumstance. However, I’d think that if you’re consistently going high from intervals, you might try a larger bolus about an hour before starting. Frustrating!


I’ve been T1 for a year, my son for 10. He was never a morning person, and hated eating in the morning. Before Ice Hockey, I’d check his blood and if he was in a comfortable range (say 80 to 100) I might give him 2 units humalog before he’d hit the ice. This is without any food.

If I didn’t, he’d come off the ice in the 300’s. His Ped. Endocrinologist looked like he wanted to call children’s services on me!
You need to experiment and see what works for you, hope that helps.

I have the same problem after only one hour of workout and can’t seem to figure it out either! From 85 before it hikes to 245 after and it’s really annoying the hell out of me… any piece of advice is very welcome, thanks.

Bradford is right on. High intensity workouts and races will cause my blood sugar to go up. I wrote a post about it on my blog at http://annetics.blogspot.com/2011/02/intensity-and-blood-sugar.html.

When I have a race, I increase my basal rate sometimes up to +40% 4 hours beforehand. Three hours out I eat my meal and take a full bolus. Having the high temp rate on board for an hour beforehand helps to keep the breakfast from blowing up my BG. About an hour before, depending on where my BG is, I will bring my basal rate back to normal or closer to normal. Depending on the event (bike races usually cause my BG to rise at least for the first couple hours) I may keep it still elevated.

For workouts, I usually don’t have the pre-workout anxiety or whatever it is that causes my BG to go up. But I do avoid, out of convenience mostly, eating anything that would require more than a unit of insulin. And I try to do this at least an hour beforehand. Usually if I eat a snack right before I start, I might get away without bolusing much for it.

But what you are experiencing is very common in athletes.

Hi Sara (and John),

I recently started giving 1.5 units of novolog about 20 minutes before my crossfit-style workouts. Before I did this, I noticed a consistent pattern of a rise of 100-150 mg/dl in blood sugar post-workout. I had always heard that exercise lowered blood sugar, so it took me awhile to feel comfortable giving an injection before working out. But, after studying my numbers for some time, I finally tried it and it worked great. Now, my sugar will only be about 20 points higher post-workout, and levels off nicely in the hours after. My case seemed pretty parallel to John’s son. Keep your diet consistent for awhile and track the rises so you know what kind of insulin to give beforehand if that’s what you decide to do.

I have done a combination of different workouts and have never seen a rise in bg, but rather a drop. I usually dont take insulin after workouts because my metabolism is pumping so fast, but I have been a diabetic less than ten years. Does this just vary with everyone or can I expect my sugar to start rising after workouts in the future?

But do you take insulin before workout?

I finally managed to sort the problem out! In fact it’s all to do with what I eat prior to the workout. I chose to focus on low glycemic index food (http://www.montignac.com/en/ig_recherche.php), if I get a post-prandial of 1.20 before workout I tend to end up with .85 to 1.00 afterwards. It sometimes gets lower then I have an orange juice and everything gets back to normal. Hope it works for you too :slight_smile:

That’s an interesting discovery! I notice that when I eat less, I don’t have as many problems when I eat less but i didn’t consider GI, mostly because I feel like I would need a to read a book to figure that out and how to adjust things to implement that and I am lazy and generally prefer reading trashy science fiction novels!! Thanks for the insight and the link to the useful website!

You’re very welcome! Hope it helps more diabetics to figure/sort out their problem with workout!

So what are you eating to fuel you for your workouts? I need ideas. Also, do you take your usual insulin dose or reduce?

I have experience on a varsity 8 many years ago. Since I’m a glutton for punishment, I bought a Concept 2 erg that I use to workout on now. I do 5000 meters three or more times a week during winter; in the summer I alternate the erg with running. What I love about an erg workout is that I can burn 333 calories in 20 minutes. What I hate about it is that its an erg workout - I need to row to music (ipod) to distract myself.

Are you on a team or rowing on your own? It’s harder if you’re on a team since the coach decides a lot of stuff (like practice schedule).

Assuming you’re not on a team, I have found that if I row prior to a meal (when no bolus insulin is in my system), that my BG stays stable. My normal basal rate is fine (I use MDI not a pump so I couldn’t turn my basal down if I wanted to) and I don’t need any carb before or during the row. I’m rowing pretty hard (5000 meters in 20 minutes). I then take my normal bolus insulin and eat soon after I row.

This wouldn’t work if I were doing a longer workout, or if I was out on the water doing sprints. A longer workout would require sugar at some point. I stick with the 5000 meters and eating after rowing (instead of before) since its predictable for me now at this point. When I was on a team back in college I used to row with a bag of jelly beans in the boat - one memorable practice they slipped away from me and got scattered all over the boat. Coach Parker wasn’t very amused - but it sure seems funny to me now. So it is definitely more challenging when you’re on a team and don’t have complete control over what you do and when.