Light headed sessions

Not sure if this is the area for this question, but sometimes say 1 in 3 when I train or ride, I find about 20-30 minutes in I get light headed and sudden heavy sweats. Lasts for a few minutes then gradually clears. Always 20-30 minutes in and never after. Could this be food related? I have no medical conditions or issues.

That sounds potentially dangerous to me, especially if it happens outdoors and you’re in traffic.

I’m not a doc or anything medical, and it might be a good idea to mention it to your doc and have them check you out again.


  • do you have low blood pressure? Do you feel light headed or faint in other parts of your life?
  • do you measure your heart rate? Is there anything happening during those episodes?
  • how long have you been training, and how dit do you feel in general? Does it happen when you go running or when doing other sports?
  • you think it might be food related - when do you usually eat before riding? And how much?

To me, it sounds like your body is moving blood supply to your legs, and taking a bit too much from the head in the process. A full stomach might make it worse, because blood will also be needed for digestion.

As I said, I’m not a medical professional, and they might know much better what is happening.

Go to see a doctor. See this:

Yeah I’ve been to the doctors and no issues found all healthy, heart rate doesn’t do anything weird I wondered if it was a sugar thing. I also had this yesterday whilst walking after 2 miled and it was hot , obviously indoor turbo so maybe heat ? Just wondered if anyone else has had the same.

Thanks guys all advice helps. I’ve been riding and training for years so not doing anything new but I am 48 do maybe should calm down a little.

A blood glucose meter is very cheap, and you could get some data during your rides pretty easily. If it’s not fueling, then it’s probably something with bloodpressure. Exercise usually causes your blood vessels to expand which reduces your bp. It could be you go into workouts underhydrated and the initial vasodilation is more than your blood volume can support. You could test this by loading some salt (1/2 tsp or so) an hour or 2 before a workout.

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Thanks Gcarver I will do a little testing to see what happens.

i’ve experienced this as well. Seemed to be when I ate a high carb breakfast, specifically, oatmeal. Even if I had some protein with it, I would still get a bit lightheaded. I stopped with the pre-workout oatmeal and the lightheadness has gone away. Only anecdotal so please take it as such.