sudden lightheadedness

That's a scary feeling!

Hypoglycemia, maybe?

Have you checked your blood sugar?

Any other symptoms, like shakiness, cold sweat?

How did the lightheadedness pass? Did you eat or drink anything?

Thank you, I am unsure if I was dehydrated or is it because of the barley juice that I drank. I am stopping that supplement since my feeling bad are usually on days I am taking that (I stopped that for 1 week and the symptoms, lightheadedness, diarrhea, fatigue went away). Although I checked all the write-ups and articles I can find on the internet and it was not supposed do to that. My blood pressure now is 125/80 and 96 BPM. My bpm is usually high but it goes to an average of 82 while resting.. It goes to 110 when I walk or exercise but when I seat down it falls down so I am not worried... Also, I think I am having some vision problems or at 47, my eyes and brains are becoming confused as my astigmatism might be worsening at this age.. Thank you for the reply

You probably need to get a blood glucose monitor and check your glucose levels when fasting. When I’m doing IF I watch my glucose level closely. When it’s to low I become light headed.

Some bodies are not made for intermittent fasting. For all of my life, I have been unable to do it without ill effects. I found myself "accidentally" doing it Sunday during a bit of a stressful situation, and got into my car. When I fumbled for the starter button (recently switched cars) I knew enough to get out of my car and grab a protein shake to drink before driving off. Without it I would have been a danger on the road.
The advice to get a blood glucose monitor to use when fasting is a good one. Feeling lightheaded and dazed (some call it brain fog) are signs of low blood sugar, which can be dangerous. Perhaps you will need to modify your fasting plan - I know my maximum interval is 8 hours and I must eat first thing in the morning, so listen to your body.
Are you on this plan for weight loss or general fitness? Did you have a thorough physical before you started?
Sue

@jfching you did not say if you are diabetic but I assume so since you are posting in the Diabetes & Endocrinology group. As others have said, lightheadedness can be a symptom of too low blood sugar. Also the suggestions of getting a glucometer to monitor blood sugar is a great idea. Diabetes treatment usually includes blood sugar monitoring, an eating plan, exercise and often medication. Intermittent fasting can be really tricky especially if you are on insulin. A dietician / nutritionist can help you customize an eating plan tailored to your specific needs. What treatments are you currently using? Do you have professional providers to advise you?

If you suspect it is blood glucose related invest in a continuous glucose monitor. They last about 14 days. Also, get the Cronometer app and put in your food intake. A dietitian will most likely want you to keep a good journal so you will be giving her very comprehensive info to make professional decisions. You can waste you time and money on a professional but you may also make associations between your symptoms, food intake, and blood glucose on your own. Worth the money and the CGM you can set up an alarm for high and low blood sugars. I never knew I had nocturnal hypoglycemia until I got a CGM. Be forewarned however, they are inaccurate the first 48 hours. This being said if your lightheadedness leads to falls get medical attention immediately. -Amy T, also a RDN

Thank you all for your kind comments. It was the doctor who made me fast and wanted me to do 16 hours. I only did 14 hours. I also half my dose of metformin during mornings (when I fast) and had a full dose in the evening. For the past few days of doing that, there was incidence of lightheadedness.

Thank you again

May I ask why the fasting? Did you immediately try to jump into the 16 hour fast, or did you work up to it gradually? Any major change in eating patterns should be done in steps, especially when you are taking a medication.
Did you report the problem to your doctor?
Sue

Thank you so much, yes it was sudden and was not gradual.. but I was on on and off intermittent fasting for a year (since September 2023). I only became very serious this year 2024 after that scare. It was the doctor that taught me to fast intermittently to control my blood sugar. I think my blood sugar is in control (I got 126 reading an hour after eating (normal range).

Thanks again

I am glad to hear that your blood sugar is under control. That alone, is a scary situation to have to face. Proud of you to hear you reversed this with diet by yourself. It really takes a strong individual to just go in and tear down old unhealthy patterns like that. What an inspiration, you are. Can I ask what the benefit of the barley juice is?, please? I been doing some research on barley and as it turns out I found out the main helpful ingredient in it was outlawed by the FDA, some years back… does juice have the same benefits? Thanks so much, in advance