Many actions are controlled by autonomic nerves, except some, like breathing, can be interfered by the conscious, while others, like the beating of the heart, cannot. In fact, for breathing, the conscious decision can override the autonomic nerves such as holding your breath until a certain point. It’s like an admin user vs a guest user. But how does such privilege system work in terms of neurons? How does the control alternate between the conscious and the autonomic system?
“You are now manually beating your heart”. Nope, that doesn’t work no matter how hard you try it (except for Buddha monks I suppose), so does this mean there are no physical neuron connections between the conscious and the heart?
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Much of the oxygen you inhale, you exhale right back out. With proper training and conditioning a deep breath can provide minutes of oxygen. Therefore it’s not necessary to have such access control limits on breathing. Especially since there are times when you *need* to arrest respiration.
Also with training you can slow your heart rate, but you cannot stop it completely…and, you wouldn’t want to. Oxygen gets to your brain by your heart pumping oxygen rich blood to it. After your brain stops receiving oxygen your brain cells begin to die. You lose almost 2 million neurons per minute without oxygen. It would be a massive design flaw or evolutionary maladaptation if the host could induce a stroke at will… especially if the heart doesn’t restart as kick-starting the heart is trickier than the lungs.
You can control your breathing because you can control your diaphragm and the muscles of your thoracic cage by demand.
The heart, on the other hand, isn’t receiving a signal from your brain for every beat. The heart itself fires the signal that causes it to beat on it’s own. That signal is produced by the SA node of the heart (basically the heart’s pacemaker) with no direct intervention from the brain whatsoever.
There is a bundle of neurons connected to the nerves that control the diaphragm. Some of those neurons are under conscious control, and some are automatic, controlled primarily by a reflex linked to carbon dioxide levels in the blood. In general, you can override the reflex, and stop/start breathing. But as the carbon dioxide level in the blood increases, that reflex action potential gets higher, and when it is higher than your conscious effort to not breathe, you will inhale involuntarily.
You cannot manually strangle yourself, or hold your breathe to die – once you lose consciousness, you start breathing again.
It’s an action you do naturally but also have control over if needed. When you walk, you don’t think about how each muscle needs to move in concert to properly move. If you try, you’ll stumble for a bit then you’ll get the gist and be able to do it. Try playing QWAP or whatever the game for walking was called. For breathing its important that you automatically breathe (think sleeping) but sometimes you need manual control (holding your breath while swimming or for any meditation exercise). If you aren’t thinking about it, your mind subconsciously takes care of it, if you think about it it’s consciously controlled. Also I hate that I’m now doing it. It sucks.
Your heart makes its own electricity. It basically performs by itself. Not indefinitely, but this is why a heart can continue to beat even when it’s outside of a person’s body, and why you can electrically shock someone’s heart when they’re under cardiac arrest to restart it without needing brain surgery.
There’s some communication between the heart and brain, but not nearly as much as the brain and lungs. Your lungs can’t breathe on their own, they are entirely dependent on your brain, and your brain is you. It’s kind of like the lungs are your newborn child that you must do everything for while your heart is your preteen child–you can tell it what to do and you can help it along and it can’t *really* live on its own, but for the most part it is its own entity and there’s only so much control you have over it.
To put it simply humans have evolved to think about things. We have not evolved to NOT think about something.
As an example, don’t think about a pink elephant. Unless we actively try to avoid reading the sentence altogether we will generally be stuck thinking about what is desired for us to not think about.
In processing the sentence you have to think about it before you can reject it. We cannot reject it before we understand it. Understanding it has an impact on our mental state which impacts our physical before we can even attempt to reject.
Effectively this is why athletes are taught to visualize what they want to happen. Avoiding, at all costs, visualizing what they don’t want to happen. If you focus on what you want to occur it is far easier to manifest yourself to do it.
Breathing is the one main area where our conscious and subconscious are shared.
That’s why slow deliberate breathing helps calm down the rest of our bodies functions like heart rate.
You can control your heart to an extent, by choosing to exert, or practicing calming and slowing it. But you can’t just think it to stop, like you can think it to stop breathing, that is true. Which is interesting, bc both processes are controlled by muscles and nerves.
Others have explained the mechanisms that make your heart beat but as for why we evolved manual breathing? That has some easy answers. If your underwater or in a toxic environment then automatically breathing would kill you very quickly. There’s just no survival based reason to “hold your heartbeat”.
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