ELI5, Why does when the heart stops, the person immediately collapses? When in contrast we are able to do aerobics, hold our breath etc and nothing happens?
In: 0
You might understand already oxygen is transported by red blood cells. When you do aerobics, the rest of your body requires more oxygen, and your heart and lungs increase their performance to match. When you hold your breath, you’re just temporarily stopping the intake of more oxygen, using what you already have in your lungs and bloodstream.
With an artery blockage or cardiac arrest (heart stoppage) your blood is no longer flowing. Your cells only have what they had stored to begin with, with no replenishment from the bloodstream. A person will very quickly run out of energy in that case and be unable to do much more than keel over.
That’s where CPR comes in. When a person’s heart is stopped or in abnormal rhythm, chest compressions manually push on the heart to get their blood circulating. There’s enough oxygen in the blood (and maybe a little bit from mouth-to-mouth breaths) to keep someone alive for a little while in this case until they get proper medical attention.
We’re usually aware that a person’s heart has stopped *when* they collapse. That doesn’t mean it stopped right that second. Their body may have carried on as normal for a few seconds to a minute on the leftover energy after the blood stopped delivering new energy.
That makes it very similar to holding your breath. You can’t hold your breath for much longer than a minute. If someone went longer without oxygen, they too would collapse and die.
Latest Answers