I don't know, man, I've had low blood sugar (LBS) numerous times but never had the double vision (DV). My LBS has usually made itself known by feeling shaky and by starting to sweat for no reason, e,g, even when it is cold outside and/or in the house, but i've never had the DV. Of course, this is just my "anecdotal experience", but this has happened to me off and on for many years, prob around 40 to 50 times total. FWIW, if I just ride it out and don't eat, then the sweating stops and i just get cold, which is kind of odd but that is what happens. In fact, getting cold when i should feel warm is one way i know that i'm really hungry, i.e., i've gotten really good at ignoring the normal hunger signals, which go away if you ignore them long enough:)

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"Anyone can be who they want to be IF they have the HUNGER and the DRIVE."

Occasionally during morning runs I'll end up with "sun spots", but typically only when i'm running with a headlamp or get a full-on blast from a car's headlights. I believe it's related to either lower blood sugar, but i'm not 100% positive.

I've never had double vision, but thought you may have experienced some other form of altered vision.

~DE

That's not from low blood sugar. Go see your doctor.

I've gotten the "sun spots" all my life simply from looking too directly at the sun or other bright lights like a car's headlights. I've always figured that everyone gets these, since my Mom told me it was normal when i was like 6 or 7, and said "Son, just don't look at sun so directly"...:) No other "altered vision" ever.

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"Anyone can be who they want to be IF they have the HUNGER and the DRIVE."

Eat more food!

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Trust me I’m a doctor!
Well, I have a PhD :-)

I'm not a doctor (but was a paramedic). Double vision alone is unlikely to be a manifestation of low blood sugar I'm assuming you really did "feel great" otherwise.

If you felt off in other ways, that would be more indicative of hypoglycemia.

ok. I talked with a doctor in the family. Her opinion is that a drug that I sometimes take is not metabolized correctly with low blood sugar. And, if not metabolized correctly, it might cause impaired vision.
But, that is just a theory. I'm scheduled to have blood tests Monday.
thanks!

I've had this a few times while running and it was from low blood sugar. Affects different people in different ways. However this is because I'm diabetic so it's easily explainable. IF yours is due to LBS then the only recourse is to find something with sugar in ASAP. Personally I take a gel with me on all long runs, or some money if I'm within striking distance of a shop. But, again, this is because I'm diabetic so may not apply to you. After taking on sugar I can continue running fairly quickly. Did you have other symptoms too? With me it was accompanied by feeling sluggish and spaced out. Classic low blood sugar feelings. If in doubt, go see a doctor!

It is extremely unlikely that someone who was not taking diabetes meds would get low enough blood sugar to get major symptoms. It would also be very unlikely that the only manifestation of low blood sugar would be double vision. I have never heard of drugs being metabolized differently in the setting of low blood sugar. Given all that, if you run after not eating for 14 hours, I'd imagine you could get all sorts of symptoms.

"I am sure I had low blood sugar". How would you know that? Have you had documented low blood sugars in the past with symptoms?

Twice in my life, after majorly overdoing it (once, riding with a friend who was a national level cyclist and keeping up while killing myself for 2 hours; second time, windsurfing all day after caning it all night), I have suffered from impaired vision. Not seeing double, but seeing bright coloured lights in the corner of my vision field that gradually crept across my field of vision and then receded. Lasted about half an hour. Scary at the time, but these episodes were both years ago, so I'm ok.

A doctor told me it was almost certainly migraine aura without pain - apparently you can get some migraine symptoms without the one most people think of, an excrutiating headache.

Maybe your visual disturbances could be this? Obviously you should see a doctor.

I used to get sun spots constantly during my early morning runs and it wasn't from looking at oncoming cars or the sun (it was too early so it was still dark). I could actually see them coming and growing as I kept running. Always at the 15-20 min mark. I stopped eating any food before the runs and it went away, which makes me think it definitely has to do with blood sugar.

To get rid of them I just stopped for 1-2 minutes, stretched and started running again once they were gone and they would go away.

Tovi - this sounds almost identical to what I experience.

You said that you stopped eating prior to your AM runs, and that helped? That seems strange. Does this have something to do with how the body transitions energy sources/systems when going from resting/fasting to after recently consuming calories?

Clearly i'm not a doctor or nutritionist....


~DE

Someone on here on ST once explained what was happening but it had something to do with insulin spikes or drops caused by the breakfast or something like that.

Thanks for posting this. I OFTEN get very dizzy when I get up, to the point where I have to hold on to something for a bit, and feel like I'm on the edge of passing out. I already know that I have low blood pressure. My Doctor told me to consume more salt?

Not so much double vision as black spots.

BTW, if anyone knows, is there a correlation between low resting HR and low blood pressure? My resting HR is 36

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Cervelo R3 and Cannondale Synapse, Argon18 Electron Track Bike

i had double vision at the end of the IMAZ bike. It disappeared by the time i started the run...but was pretty freaky. I was really dehydrated and never recovered form that...but i dont think i had low blood sugar.

i had double vision at the end of the IMAZ bike. It disappeared by the time i started the run...but was pretty freaky. I was really dehydrated and never recovered form that...but i dont think i had low blood sugar.

This occassionally happens to me during runs, at usually 10 to 15 mins.
It always coincides with having ingested high sugar food or fluid 30 to 70 mins pre run. Stopping for a minute or two and walking usually fixes it, I would guess a gel might do the same. The theory is that the sugar spikes your insulin and your BSL drops and the exercise lowers it further causing the symptoms. I find that a sugary drink or food in the 1/2hour before the run counters this.

This is very common. One cause of this is also dehydration. Many of us don't drink enough during the day. I've started to try to remember to get up slowly and let my blood flow normalize, otherwise I have to stop and hold on to something until my vision returns.

Thats called Orthostatic hypotension- happens to people who are dehydrated and/or have low HRs. When you stand up, gravity pulls your blood down out of your brain. If your heart is beating slowly or your BP is low, it takes a couple of seconds for your heart to push fresh blood back up into your brain. If you stand up slowly, you will have less problems in that department.

Getting more salt in your diet will help hold onto fluid volume in your bloodstream, so your BP will be higher, and it will be easier for your heart to resupply your brain. My mom has similar issues, so she now has "prescription" lime flavored tortilla chips about once a day :)

This happened to me the other day. I ate quite a lot of chocolate covered caramels about an hour before I ran. At 25 minutes I couldn't focus and felt like I was bonking. I ran 7-8 more minutes and it didn't get better. It hasn't happened to me in a long time and I have never been able to run through it. This time it took me about 10 minutes after I stopped running before I back to normal. It's reactive/postprandnial hypoglycemia and blurry/double visions is a common symptom. Not sure if this applies to the OP.