Hypos during Exercising

Hello All,

I have recently been diagnosed with T1. I'm an avid cyclist and ride to work most days. About 25km each way.

My Endo has encouraged exercise however I keep finding that I am going low most days on my ride home. I even have carbs and sugar prior to leaving work to get my BSL at around 9mmol, however about 3/4 on the way home I usually start to feel the signs of a Hypo and my BSL drops to about 3.0mmol.

Its got a point where I cant even be bothered exercising as I am getting too many lows.

Any suggestions?

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Hi Shoehorn,

Are you on mdi? If you’re on a pump you can reduce your basal. The only thing I can think of is to eat more and get your bg significantly higher before and then eat while you’re riding too maybe?

Are you on a pump or injections?

Im on injections, 9 units of Lantus and usually 3 units of Novorapid prior to meals

On a side note, I was soo excited prior to being diagnosed with T1 as I was losing all this weight, now I have put back 10kgs and it doesn't matter how much I exercise I cant get back to my goal weight. So the last thing I want to be doing is eating more while exercising

I would suggest the following to be used on a mix and match basis (IOW, some combination may work):

Eat some protein as a snack an hour before cycling home. You will have to experiment some to get the right amount.

Consider splitting your Lantus dose in half. Take the first dose in the morning, say 6 o'clock, then take the second AFTER you get home from the ride.

If your mid-day meal is 4 - 5 hours before you start your ride home, consider reducing your Novorapid to 1 - 2 units (can you do half units?).

Your weight loss was part of having undiagnosed diabetes. Now that you are taking insulin and able to use the energy from the food you eat, you will gain back weight. This is to be expected. Once you have stabilized, you can begin to focus on getting to an ideal, realistic weight.

Thanks for the feedback Mike.

I cant do half units, also I am still honeymooning and I find that my BSL's fluctuate for no reason...this diabetic thing can be quite irritating.

I am meeting with my Endo in a few weeks so I will discuss splitting up the lantus and see if he agrees.

Also I read somewhere that if I reduce my insulin dosage it will assist in losing a few kgs? Im not really overweight, but would like to be 5kgs lighter.

You might talk to your doctor about trying out Levemir for your basal. Lantus acts for ~24 hours while Levemir is ~12ish. This could help the excercise by having a lower basal dose in the morning and a bit more in the evening. Your doc would know better than me what dosing you could try. I found splitting my Lantus dose had little affect since it stays in the system for so long.
I agree with Mike, try a mixed protein/carb snack ~1-1.5 hrs before the ride home. That way the carbs in it will peak mid ride home. Timing for it is something you'll just have to learn via trial and error.
If you are indeed an avid cyclist, I'd definitely have a talk to your doc about getting an insulin pump. Being able to adjust basal rates for a couple hours at a time just can't be mimicked on MDI. Do some reading about different pumps on the internet to see if they might appeal to you.

Have you been reading books? Sounds like you should decrease your insulin intake. Ditto on the pump, it might solve the problem because you could turn your basal way back before cycling.

Injecting Insulin
Think like a Pancreas
Dr Bernstein's Diabetes Experiment
Your Diabetes Science Experiment

I think that it may be easier to toss some extra carbs, like 5-10G down to see if that can "cover" the ride home? I agree too that investigating basal insulins may be interesting but carbs are way easier to come by!

I had the same issue, my health care team told me to try reducing my basil rate by half for 3 hours. 1hour before 1 hour during and 1 hour after, it worked now I don't have to bulk up on carbs during exercise which was awesome. still needed to keep some dex tabs on hand though when I over did it. each time is different

If you're gaining weight try switching to levemir, lantus is known to cause weight gain. I was starting to gain weight and switched to levemir and then stayed stable.

You can reduce your basal insulin, and also any bolus that happens within about five hours of exercise. Exercise will slow digestion and speed up insulin, so having insulin on board sets you up for a low. Being able to shut down or reduce your basal temporarily is probably the biggest benefit of a pump, if that’s an option down the road.

In my opinion, carbs used to raise your blood sugar from a low to normal levels during exercise do no contribute to weight gain. Excess carbs may contribute to weight gain but not measured amounts, but not carbs to treat a low. My reasoning is that all that glucose is taken up by your body to restore normal blood sugars and none of it results in blood sugars higher than normal and the resulting conversion of the excess glucose into bodyfat.

One way of managing lows during exercise is to just take measured amounts of glucose during your bike ride home. Perhaps one tab every 10 minutes, taking the first a few minutes before you start. I carry little bags of valentines sweet tarts that are pure glucose and each litte sweet tart is like 1g of carb allowing me to treat a low without doing excess carbs. This method can work well when you are consistently going low, but not so much if your blood sugar is highly variable.

ps. Is your A1c really 4.7%? That may explain some of the lows.

The cardinal rule with Type 1 is essentially matching your insulin to your intake of calories. I'm no expert, but there are other, better steps to take "to losing a few kgs" (if that's actually necessary). These include not only what you eat and how much, but when you eat. Exercising of course, is also key, but so is just being active.

I would discuss your weight goals with your endo.

Even correction calories can't violate the laws of thermodynamics. If you eat more, unless you burn or excrete more at the same time, you will gain (or lose less) weight. This is one reason moving from MDI to a pump can result in weight loss, because on MDI, one has to correct against a constant basal, whereas on a pump, one can tailor the basal to times of day, activity levels, etc.

Drink some gatorade halfway through.

Eat more.

It sounds like your long acting insulin levels are too high on days when you ride your bike. I usually have to cut back by at least a few units per day when I work out. I would try cutting back on your long acting insulin that day and don’t change the rest of your routine. See what happens. If you find yourself crashing during the day between meals and during exercise, it’s usually because of your long acting insulin.

Best of luck!

Get a notebook and keep track of trials and errors… There are really only a few different variables in this equation—

  1. exertion
  2. carb intake and timing
  3. starting glucose level

Writing things down really helps to figure them out.