What causes people to pass out after Deadlifts?

[mikepurvis]

Youtube has many examples, I've seen this one several times. ORIGINAL deadlift passout video 329 - YouTube

What causes this physiologically?

Does this ever happen when someone is lifting with good form?

[MBasic]

This used to ALMOST happen to me when I first started doing heavy deadlifts (heavy for me . . . like 3RMs and 5RMs . . .that were absolute RPE 10's).

I would get real light headed and a little dizzy right after the set, for just a second.

It only happened a few times maybe the first six times attempting rep-maxes. . . .since has gone away entirely.

The guy in the video? the yelling with the double bi-ceps pose didn't help him any I'm sure . . .

I also am curious

[bugbomb]

It's never happened to me on a deadlift, but I've come close on challenging 3-5 rep press sets.

[Sam Hain]

Could it be a vasovagal reaction from compressing the Vagus nerve.

I used to always see stars after heavy(for me) deads. Not anymore though.

[MBasic]

best I could find. Johnthan Sullivan chimes in on this thread for explaination:
Deadlift 538 then I passout

[Kryptenx]

I've seen it discussed here before and would encourage you to search around for more info. Seems to be something about letting your breath out at the top and in my case it's usually if I exhale at the bottom and then stand back up too quickly. Taking a knee or sitting down for a few seconds will fix it. Seems to happen worse/easier the longer your Valsalva is held.