I'm susceptible to dizzy spells upon standing myself. Not sure if this is an issue of orthostatic tolerance or something else. I did a little research a while back and read that this is associated with significantly higher all-cause mortality. Yay for me.
I do drink plenty of water, maybe too much even, am in good shape, and have no medical conditions of any kind. Weed greatly exacerbates this issue for me, probably from the fact that it reduces blood pressure, but this can still happen when I'm not smoking for extended periods.
Recently, I figured out a way to short circuit the onset of a dizzy spell. Hyperventilating completely nips this in the bud, likely because it increases blood pressure [1]. I'd recommend trying this technique to anyone that's otherwise healthy (I am not a doctor) and coping with this issue.
If you are lean and regularly do endurance exercise, it's a known phenomenon. It's not of any concern since it won't go to the point of passing out, it's just a curious insight into the control loop that regulates our blood pressure and heartrate and that it's possible to leave the stable area, though not to the point of divergence :)
I do a lot of climbing, am fairly lean, healthy, and have a low resting heart-rate. I've also always had the problem of nearing "blackout" occasionally if I stand up very quickly from zero physical activity - I've never actually passed out, but you have this weird sensation where your vision, balance, and in extreme cases even hearing, fades to various degrees until the pressure stabilises.
I wondered if it would be a similar effect to what happens when a pilot pulls a high-g manoeuvrer.
I have this too; mostly, you just have to train yourself to stay seated for a couple seconds after laying down.
My doctor said the way you die is peeing. You wake up at night, have to pee, make it to the bathroom before getting dizzy, keel over, and hit your head.
Another technique you can try to cut off the dizziness upon standing is flex your abdominal muscles as soon as you feel it coming on. Works 100% of the time for me. Probably works for the same reason (blood pressure), but easier than hyperventilating :)
During the Valsalva maneuver (i.e., exhaling against a closed glottis or bearing down as though to defecate), intrathoracic pressure increases and leads to increased arterial pressure as a result of increased afterload. It is easily done by having the patient take a deep breath, put their thumb in their mouth with closed lips, and attempt to exhale without expelling any air.
Thanks for this suggestion, I have the same experience of lightheadedness upon standing up (very often) and will definitely be working this into a habit.
Interesting, I found that hyperventilating is actually pretty much guaranteed to cause a fainting for me. The method is to sit down as low as feasible, maybe even lie down, hyperventilate for about a minute, and then rapidly stand up. I used to do this to faint on command until I hurt myself falling on a concrete patio. Now I know this effect has a name and a possible mitigation, yay!
Very tangential, but your comment reminded me of this...
I have this weird trick where I can put the back of my tongue against the roof of my mouth, and exhale I'm a certain way that causes a whistling sound, I think where my sinuses reach my throat.
That often makes me light-headed very shortly after for some reason.
Same thing for me. I used to do it with friends when I was a teenager. Until they got the idea I was faking and let me hit the deck, expecting me to catch myself.
Try increasing your salt intake. You can test this with water + salting to taste. If you have positive results invest in salt tablets to pick up on other micronutrients you’re also missing.
I do drink plenty of water, maybe too much even, am in good shape, and have no medical conditions of any kind. Weed greatly exacerbates this issue for me, probably from the fact that it reduces blood pressure, but this can still happen when I'm not smoking for extended periods.
Recently, I figured out a way to short circuit the onset of a dizzy spell. Hyperventilating completely nips this in the bud, likely because it increases blood pressure [1]. I'd recommend trying this technique to anyone that's otherwise healthy (I am not a doctor) and coping with this issue.
[1] https://www.ahajournals.org/doi/full/10.1161/01.HYP.00000523...