AM Runs: Light-Headed, Dizzy

This could be pretty serious, so I would back off for a while and go back to cardiologist. Although it could be caused by something else, dizziness is also obviously a warning sign for heart issues. Maybe it is just low blood pressure, which is emphasized by the fact that you are now running even earlier, when your body is still in relaxed mode, but why take the risk?

AFTER you see your cardiologist again and get the go ahead to keep running, the next thing that I would focus on is nutrition - are you getting enough calories in? I sometimes get that lightheaded and dizzy feeling and see stars (more like bright spots that semi-blind me), but it is almost always after a pretty hard workout, and usually it is combined with me having not eaten enough over the course of the day to cover my calorie expenditure and effort for the workout.

Don't take any chances, and don't take medical advice from us idiots. See your doctor, even though you are reading this and thinking "Yeah, but the doc isn't going to find anything this time, just like he or she didn't find anything last time."

If it happens only in early morning, it could be hypoglycemia.

Dehydration may also play a role. Chug some water before you head out and see if that helps.

Since your previous test revealed nothing, I would suggest talking to your medical professionals about the possibility of a test to replicate the environment in which your episodes are happening. There may be a facility or research program that could monitor you on a treadmill during an early am run. Could be more enlightening as to what is happening in the moment compared to hours later? Good luck and hope you recover from your ails.

Agree w everyone who said get to a cardiologist (prefer non-invasive who will pay better attention to your story) or neurologist. I assume you are young and not at risk for cardiovascular disease. Does the symptom pass once you get going, or persist? If you do cont to run, try to keep a diary of your symptoms.

I get this same problem if I run and I'm underfueled.

I'm guessing this is almost entirely nutritionally related as you're coming off an overnight fast from dinner through the night until you wake up. When I used to run early in the morning about a mile or two in I would start to feel shaky and light headed and then my vision would start to see rings of light almost like if you glance at the sun or a bright light real quick and then look away.

I will have this same issue on an afternoon double if I don't enough during the day between runs.

I would try to get in more calories than just a granola bar when you go out. Drink some Gatorade and eat some yogurt that will get into your system quicker than something solid like a granola bar. I would also ease into your run, I've noticed that this only seems to happen to me if I sat out too hard - if I start real easy and gradually ease into a faster pace it doesn't seem to occur.

Other things to consider in anticipation of seeing doc:

Check blood pressure in morning (blood pressure kits are fairly affordable these days) when you wake up so you can give doc info;

Track food with myfitnesspal or a similar app and try to get a sense of whether you are getting enough food to fuel you through the run on an empty stomach.

Maybe take in a banana or something else easily digestible as soon as you wake up and give it 15 minutes to get into your body some before starting your run.

Treat hydration as a consistent duty, not just something that you do after a run.

There are lots of things that might be coming together to cause your issue, but you just cannot take chances on these kinds of things.

I lost a college teammate to heart issues when he was 40. He was fit, active, and otherwise healthy. He and I had gone an easy, hilly 10 miles just 3 months before he died.

Thank you for the feedback, additional inquiries, and concern.

Heart-related issues (no pun intended) scare me to death, as the majority of my immediate family have been impacted by them: my mother has had 2 heart attacks despite maintaining a healthy diet, weight, and exercise routine (though, her Lupus is likely a contributing factor); my younger brother had a cardiac ablation at age 13 to treat SVT (his HR would randomly shoot as high as 200-220 while just sitting around watching tv); my paternal grandfather had A-Fib; my maternal grandfather had 8 bypasses; one uncle on my mom's side had 2 strokes before age 50, and the other has been treated with BP medications since his mid-30's.

All that being said, I am suspicious of potentially blood sugar-related causes. Since 2015, I have had an implantable loop recorder in my chest that has yet to detect abnormality (though they are not 100% perfect).

After noticing the issue last week, I thought low blood sugar might be a cause and - on a whim - ate a handful (3-4) chocolate chip cookies pre-run one morning. The light-headedness seemed worse, though it may have been compounded by 18 miles the day before.

I used to get something similar. On morning runs I'd feel very weak and tired - just this full-body fatigue. I'd also get something weird with my vision - I'd see spots and everything seemed uncomfortably bright. I'd almost feel dissociated, like the things I was seeing weren't actually real. It was so unpleasant that I eventually stopped running in the morning entirely.

I was almost positive it was something that had to do with blood sugar. My first thought was low blood sugar since it only happened first thing in the morning. But, like you, I found that it actually got worse when I ate something beforehand, particularly if I ate something sweet and sugary. So I did a little bit more research and realized that it wasn't hypoglycemia (low blood sugar), but hyperglycemia (high blood sugar).

High blood sugar in the morning isn't uncommon. When you're body is getting ready to wake, up your liver actually starts releasing glycogen to help you get ready for the day. Normally the increase is kept in check by insulin, but going right into a run may inhibit that process in some people somehow. My guess was that running sends a signal to your liver to release even more glucose, and too much of it floods your body at once before you can mount an insulin response. For me it would only last a few miles before things seemed to normalize again, but those few miles would be pretty unpleasant and tough to get through.

I'm sure there are some scientific flaws in the above, I'm in no way a doctor, but I think the gist is right.