Do you go unconscious and die instantly the second your heart stops? If so, what causes that to happen instead of taking a little while for your brain to actually “turn off” from the lack of oxygen?


Like if you get shot in the head, your death is obviously instantaneous (in most cases) because your brain is literally gone. Does that mean that after getting shot directly in your heart, you would still be conscious for a little while until your brain stops due to the inability to get fresh blood/oxygen to it?

In: Biology

You go into shock, so while technically you remain alive for a little while, in practice you won’t really be aware of so much – not in the way you are normally.

You pass out pretty quick but the death part is not necessarily as instantaneous as you might think. Your body actually has several minutes worth of oxygen stored up (which is why a few minutes of hands-only or compression-only CPR done before rescuers with equipment arrive actually helps)

Yeh exactly it depends what you mean by death. We used to think of it as a single event, and now more so as a process, as we discovered ways to bring people back from what we used to think of as ‘dead’.
So if you get shot in the head, we say death is instantaneous. It seems obvious, but unless the bullet hits a specific part of the brain, the heart will beat for a little longer afterwards, your liver might not notice for a while etc, but we have no way currently to save someone who’s brain has stopped working due to bullet damage.

If your heart stops (let’s say from cardiac arrest instead of a bullet for this one) then the clock continues for the rest of the body (I say continue as they say we’re only ever a few minutes away from death, but each time we breathe this resets the clock). Each minute your heart is not pumping (either by itself or by CPR or something) increases your chances of dying by 10% I believe, so your body still has oxygen in it, this is quickly used up, and you’re not replenishing it, then your cells and organs start to die due to lack of oxygen. At some point (and this is an ever moving point) there will be a stage where our current medical capabilities will not be able to reverse the damage that has been done, and that point we call death.

But that’s what’s important, not the time, usually it’s a matter of minutes, but if you you have a cardiac arrest and fall into a frozen lake, breaking the ice and being surrounded by near freezing water for example, it could be a matter of hours, as the rate at which your cells die in that situation slows dramatically.

No you don’t.

We often reset the heart in ED using medication or electric shocks if people have SVT – basically a super fast heart beat.

When taking the injection the heart stops for a couple of seconds – sometimes more – and when it restarts it often goes back to normal.

People do not go unconscious during the effects of the injection but they will always feel absolutely awful until the heart starts again.

So no. We do not go unconscious as soon as our heart stops.

We will go unconscious as soon as there isn’t enough oxygen in the brain.

Actual ELI5: the heart is like the motor of a car. When you stop giving gas, you don’t immediately stop. But if you don’t start the motor again eventually you’ll stop moving

I had a major heart attack while running. I lost consciousness and fell like a ton of bricks. Skinned knees and small bite on my tongue. I was out for about 20 seconds when I came to (cardiologist said my heart stopped and was “stunned”. I came to with no assist which was witnessed by several medics. It was like a dream but it wasn’t like Fred Sanford yelling “I see the light Elizabeth.”

My biggest fear upon death are the “Death Dreams”. The state the brain is in when it is deprived of oxygen just before death.

Depending on the efficiency of your heart (ejection fraction and a few other parameters), if your heart stopped, your pressure would tank and you would lose consciousness pretty quickly, although, you would not be dead or even brain dead for a few minutes. The pressure created by your heart adds to the ability of your body to exchange oxygenated blood with deoxygenated blood!

Source: pacemaker technician.. sometimes people go sleepy if you run a test too long! 😅

No, you don’t. You stay conscious for a few tens of seconds.

Apparently, back when smoking was common and good safety procedures were not yet universal, you’d occasionally find an electrical maintenance person dead next to a fuse box, holding a cigarette. The maintenance person had touched a live wire inside the box with their right hand while holding the grounded metal of the box open with their left hand and thought they’d received a non-fatal shock, when the shock had in fact silently stopped their heart. Then they’d start feeling tired from insufficient blood flow, and get out a cigarette because nicotine is a stimulant. Then they’d fall unconscious and eventually die.

Slightly off topic but anyone who really wants to scare themselves should go read about CPR induced consciousness. I personally have been unlucky enough to see a man open his eyes while we were doing cpr on him. He also bit the lyrangoscope when the doctor tried to intubate him. And yes we were absolutely sure he was dead and in need of cpr. This is the same man that confidently walked into our cardiac room and said “I am having a heart attack, this is my fourth one and I am going to die this time”. He was right.

Some areas are actually looking into sedation protocols for cardiac arrest, though I’m unsure if any have been implemented.

It takes around 6-12 second of no heart beat before you black out (depends a bit on how good your body can handle changes in blood pressure). Your brain needs a certain blood pressure to be conscious and your heart beating Is what makes that blood pressure.

So yeah, you may be conscious for a few seconds while your heart is stopped before you blackout and then die if it doesn’t restart (or get cpr) within a few minutes.

It’s pretty haunting to watch.

Here’s to dying in your sleep.

Things that stop your heart are often doing other bad shit too. Sometimes your brain intentionally shuts down to preserve itself if there’s, eg, a sudden drop in blood pressure.

You’re aware for at least a few seconds afterwards. When I was 6 years old, chasing some kids on the playground, my heart suddenly stopped beating. It was pounding hard as I ran, and then the sudden lack of pounding made me stop cold. I put my hand on my chest, and everything started to look splotchy. I remember a ring of blackness in my vision took over, and grew from the peripheral inward, until all I saw was a pinpoint in the center of my vision. My knees must have buckled at that moment, because the last thing I saw was myself falling involuntarily. I hit the ground, and felt this extremely hard, painful BANG in my chest. I don’t know if it was from the shock of hitting the ground or my heart just turning itself back on, but the beat was back, and my vision returned immediately. I was totally freaked out. Everyone was staring at me wondering why I just stopped running and fell. Yard duty teachers were walking up to me, but I was too embarrassed to tell anyone what had just happened. I remember my chest seriously hurt the rest of the day, but it was years before I told anyone. Also, unrelated, I had a dream in my mid 20’s where I was in France, dressed in rags, different body than mine. I was on a platform in front of tons of cheering people, full on about to be executed via guillotine. I remember the sound and rumble of the blade as it was released and falling. The strike. And I vividly remember seeing everything and everyone’s faces tumble as my head rolled off the short platform. I knew I was dead. My sight faded as my head was in mid-air, and was gone before it hit the ground (or basket-I don’t know). I know it was just a dream, but I have really searched for all these years for confirmation that that would be an accurate experience for someone going through that. It seems to add up. It was a terrifying thing to wake from. I don’t recommend it.

I can actually chime in on this. I had a cardiac arrest in 2018 and was rescued by a passer by. I dropped because my heart stop, but I started Agonal breathing. Your brain stem senses the lack of blood and sends out pulses I believe. My savior did CPR for 18 minutes and then I was shocked in the ambulance.

The brain *very quickly* notices that the oxygen level sinks, and breathing goes through the ceiling. Without much success, though. You’ll get an adrenaline boost. But you stay conscious for a short while. But that’s not fun, as there is only one thing on your mind: *PANIC*. I can tell you, it’s not funny. 0/10, can’t recommend.

I was lucky, my heart restarted from one of the fail-safe circuits the body has, or else I would not type this.

My heart has stopped a few times but came back on its own. The experience is one of mild panic while fading to black over some seconds. Then my heart picks back up again beating very fast and I’m full of adrenaline and then actually feeling panic.

Also had my heart go to over 300 bpm and needed to be shocked back into rhythm.

Im not a drug abuser or anything, I just have a sinoatrial node that likes to do its own thing.

I experienced this… you def. are conscious. When I was pregnant I had undiagnosed gestational diabetes. It messed with me in many ways, one of them being heart arrhythmias. One day I was at a park with my mom and my first kid and i felt really “off”… so I returned home with them… once there I went into a bedroom and laid down. My heart started racing, then it did a loud THUMP and dead stopped….. I was like what the fuck… I was all alone in the room and knew my heart wasn’t beating and oh my god I’m going to die and I can’t even get up to tell anyone, they will just find me dead….
I started to count, knowing things would go black soon… I got to about 10 seconds and started to feel tingly like I was passing out, and I’m thinking fuck so this is how It ends….then two huge THUMP! THUMP! And then it just started beating regularly, the tingling went away and I’m left thinking