Thanks for your detailed response! It’s interesting you mention the flashing black spots, I actually started noticing that a couple years ago during an extremely stressful time of my life. They’ve never really gone away and I also so an optometrist about them, he said it’s not related to my eyes.
It does sounds like restricting your food/fuel intake at the same time as you are putting energy demands on your body might be something to look at…
There is a chance that a typical doctor will not necessarily understand the sort of mindset or demands etc for an endurance athlete and give you advice which would be more appropriate for a typical adult, not one that thinks riding a bike for 5 hours is a normal thing to do.
If Doc comes back with generic advice like “stop riding” then go find a different doc that either is an athlete themselves or works with them…
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Many years ago I used to get headaches after 90minute - 2hour rides in especially hot weather despite drinking like 3L of water and confirming my before and after weight. A tylenol or ibuprofen would get me back up, but it just never made any sense. Looking back, I’m almost certain it was sodium depletion. Water without salt is not hydration, and the body is going to freak. I never get the headache anymore now that I make sure to salt load on these rides. Since you’re in the middle of a weight loss regime, I bet you’re taking in a lot less sodium than usual and just went over the edge of what your body could compensate for with the workouts you did.
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I have the same issue if I stand up quickly. I asked my doctor and he said I needed to get more electrolytes into me.
I still get it occasionally. Like mentioned in some of the above posts, you do need to take care when standing up and not spring up. I believe the guys even covered the topic in one of the podcasts and talked about the blood sitting in the legs when you stand up quickly and not circulating as much through the heart.
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I’ve had this, as everyone else on the thread, so I guess it’s not a ‘problem’, rather an effect of what we do and our bodies doing what they need to to counteract it.
First easy one is Postural Hypotension Orthostatic hypotension - Wikipedia
Next look at your hydration. (this one works for me - I have had several ‘scrolling’ heads and have not since I look after hydration more. I did this after talking with a heart specialist who knew cyclists with the same issue, and they found that proper hydration worked for them too)
Stress is Stress wherever it comes from. Cortisol is Cortisol.
Usual diet advice - lots of veg, lots of different coloured foods.
Then start thinking about overtraining, illness, genetics.
Oh yes, and get up more slowly 
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Yes, orthostatic hypotension. I have always had it but it has gotten worse as I have gotten older - 45 now. It used to be a non-issue, but now, most times if I crouch down and stand up, or stand up out of a chair too fast, it is 50/50 that I will get super dizzy. Usually only lasts ~30 seconds, but sometimes get the headache you are talking about. It is also one of the symptoms of POTS - POTS: Causes, Symptoms, Diagnosis & Treatment
Also, work/family stress and lack of sleep can have an enormous impact on your health. I have seen it first hand over the last 4 years.
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Hi, I’m hoping to hear back from TRusername. I’ve had a couple of episodes in the last two weeks that are very similar. And my fading out, which was leading to blacking out was happening while I was driving later in the day. A bit scary. I also had a hangover from it. Headache, pale face, and just being washed out. I thought maybe it was a lack of sugar and pushing myself too hard on the rides. Today, I was out on a ride and it started to happen again in the middle of the ride about 2 hours into it. I’m a little bit concerned as one of the guys in the group said that another cyclist had something similar and it was a clogged artery. He needed a stint. Anyway, will check in later but will be going to the doctors to figure it out.
Yeah dawg that a go to the doctor kinda thing. Its pretty normal to feel lightheaded and get some low blood pressure symptoms when you are sitting to standing and such, but if you are knee deep in activity and are still having persistent issues one hundo pee talk to your dr. It could be something like salt or nutrition but if its persistent and you have tried a few things, I think the doctor is the best way to go.
Kids with congenital heart defects often squat down and grunt to increase venous return to the heart to help maintain BP. Lightheadedness after working out is often due to dilatation of the large vascular beds in the legs and subsequent pooling of blood. I find the “squat and grunt” works pretty well to correct the problem.
My doctor put me on a halter monitor and it turns out I have something called right bundle branch blockage, it’s an issue where there’s a delay in the electrical signals that cause your heart to beat. In general it’s not an issue and most people who have it don’t even know. That said, it can cause fainting or near-fainting episodes.
Your issue may be different though, so I think your decision to see a doctor is well made.
Hi! Could you please share that podcast?? Where could I find it?
Found nothing after spending two minutes searching. Sorry I couldn’t come up with the right search terms to quickly find it. You might want to look at podcasts from August and September 2019.
New to TR. Persistent issue with dizzy episodes for years. Been passing it off as normal but maybe I shouldn’t. Never occurs during a ride. Always occurs afterwards once home and relaxing. Get up and nearly faint. Freaks out my wife. Blood pressure always very low at doctors. Seems like these spells can last for 2 or 3 days after a very hard ride. I try to drink a lot with an electrolyte and consume plenty of appropriate food before and during. Before any road cycling in my life I had a period in High school junior and senior years where I could black out standing to leave a class. So I’m assuming that I just have very low blood pressure and I’m going to have to be extra careful???
Nah, I’ve got a right bundle branch blockage. It is nothing. The only effect in my experience (for pilot medicals) is that ECG tests don’t produce the right results for you so you might have to have a Doppler ECG.
I’ve asked a couple of other cardiologists about it over the years as well and they’ve said: “nah, it’s nothing”.
You may need a lot more salt than your electrolyte mix is giving you. I preload 1/4 or 1/2 tsp of salt before rides and that’s basically eliminated my risk othostatic hypotension when I get home from a long/hot ride.
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This dizziness thing just happened to me. After finding no cure at the ER, I intuitively started to to massage my occipital neck muscles in the back base of my head. The other muscles are the Sternocleidomastoid. Within a half hour, dizziness gone. Neck muscles get really tight due to the position of the body and neck. Long hour training tire these muscles out.
I have been experiencing dizziness and lightheadedness upon standing for the past several years since I have gotten more serious about cycling and it has been nothing more than a nuisance until last night. Last night I woke up around 12 or so to use the bathroom and I passed out and ended up being taken to the hospital. They did bloodwork and tested my urine and found nothing. I am going for a follow up with my primary this afternoon.
My resting heartrate is in the mid 40’s, I am 47 and about 146lbs
I have the same issue. My blood preasure is very low and my resting HR too (during the sleep avg is 32-34). But…I noticed significant improvement when I had changed the diet. I started work with a sport nutritionist and the main factor for the condition (at least for me) is what/how many I eat during the ride and directly after the ride. Now I feel that way only after really hard seasions. I mean the 120km/3000m of elevation gain race or 2h of O/U or after the zwift race if I drink not enough or/and eat not enough. The tendency is much stronger when I’m tired. After bad sleep or during the hard time at work etc. But my doctor said, it’s nothing I should be worry about. So I don’t 
I have a resting HR of about 35-36bpm and low blood pressure. I often feel a bit dizzy if I stand quickly after an evening on the sofa…has happened for years with no ill effects. That said I have never had it in a race or after/during a training session…that would worry me. I think it beats high blood pressure! 
I believe Amber covered this pretty thoroughly in a recent podcast. Seems normal for most that experience it.