So, this isn't really road cycling specific, but maybe some of you can help me out anyways.

Recently, as in the past month, I have started to feel lightheaded sometimes from standing up quickly after sitting down for too long. Happens mostly at work, and when it does I feel lightheaded, blurry vision, and dizzy. Sometimes to the point where I can't see and I feel like I'm about to faint. Happens from 1-3 seconds then everything is back to normal. I looked it up and got a lot of mixed results but mainly happens to teenagers, but I'm 21. It's been called Positional hypotension, Orthostatic hypotension, and postural hypertension, to name a few. I've been cycling a year now and have lost 60 lbs. I've never had this problems before but started having it now for some reason.

Anything to worry about?

aka "the freebie."

Happens to me all the time. My GP linked it to low blood pressure, said it's basically part and parcel of being healthy. I'm exactly twice your age, so it's not exclusive to any age group.

You've lost a ton of weight, which is fantastic, definitely you should see a doctor and have some baselines established, and keep doing what you're doing.

I have suffered from this for over 40 years; worse since I have been aggressively medicating my hypertension. Never fainted in all that time. If you can, bend over to lower you head when you feel it coming on. Also kneel down if you can to avoid injury in case you do faint. I know these things are embarrassing in public. Just make do.

As for prevention, I find that rehydrating after riding is extremely important. Also reloading electrolytes and carbs. Dehydration and low sodium are prime causes of this problem, so be sure to get your hydration, electrolyte levels back up quickly. The carbs also help.

+1 to this. I started cycling about 3 years ago (I'm 45) and this happens to me a lot more frequently than it used to and even a bit more extreme. My doctor said it's due to lower blood pressure and mine was never high but seems to be lower since I started cycling.

My typical BP is 110/60 and I get that also. If you do start to black out, sit down as quickly as you can.

Not unusual.

Best treatment is salty snack three times/day.

Rarely there are conditions like autonomic instability and shy-drager syndrome that can cause this too but highly unlikely.

Certain medicines called alpha blockers can also do this.

Get some pretzels, and get up slowly. See your physician if it does not improve.

Happens to me too. Dr. said low bp when i asked him about it when i was 17. I'm 29 now, and it still happens. Only felt like I was actually going to pass out once, so I sat back down asap. He said it was nothing to worry about as long as it didn't get any worse, which it hasn't.

Has always happened to me, my blood pressure is on the low side. A few times I have straight up blacked out, once in high school which was fun. I'm 19.

meh, "it's hurts when I do that" "well, don't do that"

You're Welcome, where can I send the bill?

Happens to me too. Doc and a few others explained it with varying explanations like blood pooling in my legs when I am crouching, etc etc. I just brace for it knowing it will happen after I recover from certain positions.

I get this as well, especially when I'm regularly exercising. In High school when i ran cross country my doc linked a combo of lower blood pressure which is natural if you're fit, and not too much you can do about, coupled with a possible temporary low blood sugar from exercising/improper diet (ahem high schooler's typical diet...) I still get it, but not nearly as much as long as I replenish electrolytes and make sure I get enough carbs early in the day to stabilize blood sugar, and fruits to help the sharp drops if i was just exercising or if i was siting for a while. I'm not diabetic, but from what i understand blood pressure and sugar levels can work in tandem to do stuff like this. for refrence I'm 23, and a pretty average build

Tell your Doc - Check your meds - Log your resting inactive heart rate...

This can happen with really fine tuned athletes - When sitting and resting their heart rate can drop all the way down to the thirty's - I have know competitive long distance runners that required intermittent pace-makers to prevent loss of consciousness when resting...

Yea, I heard being active and having a low resting heart rate can cause this, so I figured this would be a good place to ask. I might start munching on pretzels while at work since this desk job always has my HR pretty low. Just making sure I didn't have some underlying heart problems to worry about.

"Orthostatic hypotension." There's a thread on this in 50+.

I'm still "dieting" since I have about 10 lbs to go. I'm not really on a full on diet, I just eat healthy and mainly organic foods. I haven't adapted my diet to cycling, so I'm probably not eating as I should for how much I ride (~180 miles per week). I just eat healthy and a pretty well balanced meal (I think) and only change if I start gaining weight or feel abnormally tired or groggy.

its slow heart rate sometimes in combination with low blood sugar. i've actually fainted a couple of times. see your doctor if you are concerned.

I've been able to do that since I was a kid. Just... stand up slower.

Happens to me all the time. I just make sure I'm near a wall or something to lean against when I stand up.

I stopped drinking Gatorade during all my rides and am now sticking to plain water. It had a fair amount of sugar and I just realized it started happening around the time after I switched. I only drink water throughout the day but maybe I need to switch back to Gatorade?

I have had this happen to me on a very, very, regular basis all the way back to High School and I'm 41 now. I have always assumed it is because I have pretty low blood pressure, but never asked a doctor about it. Periodically I have tried to find something to make it stop but have never been successful and have assumed it is just something I have to live with. Until reading this thread I didn't realize it is so common. My "cure" is the "lean against the closest object until it goes away" method.

Could be due to low BP, low blood sugar, low resting heart rate, or something more serious. It happens to me occasionally.

I've always had this happen (38 years). My BP has always been normal. My heart rate isn't so normal (resting is in the upper 30's). I haven't died from it yet so yeah, get up slower. If you feel it happening, try leaning over a bit to make it easier to get blood to your brain. That usually corrects it quickly for me.

This is hilarious, I was just thinking about this. I notice that after cycling, I'm extremely prone to headrushes in general. Blood pooling in my legs, low heart rate and low salt levels probably all contribute.

It's a drop in blood pressure.

NOT sugar.

Pfffft - what do you know?