ELI5: Why is it good for your cardiovascular health to increase heart rate via exercise, but harmful to increase heart rate via stimulants?
ELI5: Why is it good for your cardiovascular health to increase heart rate via exercise, but harmful to increase heart rate via stimulants?
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As far as I understand it(no medical training at all) is stimlants are sudden, forced, and extreme compared to exercise which gradually builds up/allowes adaptation time
Your vascular system is like the pipes in your house, if you open all the taps and push a bunch of pressure in it’ll flush the system and be a good thing, if you push the same pressure in with all the taps closed it’s going to damage your pipes.
Your body is an immensely complex system.
There are thousands of little wheels working constantly together just to sustain you sitting in a room. Hormone levels, neurotransmitters, blood sugar, heartrate etc
Heartrate isn’t an on or off switch.
Imagine a fine handcrafted 100 year old watch. There’s nothing stopping you from breaking the glass, and turning the hand manually. But you’re breaking the watch in the Process.
Stimulants don’t just accelerate the heartrate – end of Story.
The basic question is how are they doing it. There are a lot of different ways of achieving a higher heart rate.
You can Interfere with the bodies hormone levels. You can Interfere with receptors of the heart. You can Interfere with the brain, signalling it to increase heart rate. And many more.
All these have side effects. And the things you’re using usually have an effect of multiple different Systems.
A heart Medication might be aggressive to your intestine or strain your kidneys.
Less aggressive stimulants, like Coffee also have side effects. But they’re not nearly as harmfull.
For muscle growth, it’s also more complex than just using your heart. The body also needs to send out growth factors. It’s a coordinated effort.
Basically – I dumped a lot of concrete in my garden, why isn’t It a house yet.
A lot of those drugs that raise the heart rate also clamp down your blood vessels raising your blood pressure which makes your heart have to pump against increased resistance. This overtime leads to progressive failure of the heart muscle… people who have untreated high blood pressure also get the same type of heart failure
also those drugs that are raising your blood pressure along with your heart rate can also cause spasms of the small arteries that feed your heart muscle with blood causing heart attacks
Exercise however helps strengthens the heart muscle and helps lower blood pressure over time
Exercise isn’t good for your cardiovascular health because it raises the heart rate, it’s good for your cardiovascular health and raises the heart rate.
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You actually just need to ask the question of why is exercise good?
It’s physically using your muscles, bones, tendons, ligaments, etc. and putting them under strain which causes adaptations to the exercise making them stronger over time. Heart rate increases as a mechanism to help you perform.
Stimulants don’t do any of that, they might just raise the heart rate, so you’re just comparing two side effects of different things.
Exercise is not good for you because your heart rate goes up. Actually the fact that it does when you are unfit is one of the biggest risks of doing exercise in the first place.
If you have bad heart disease, raising your heart rate through even modest exercise is enough to cause a heart attack or at the very least chest pain from lack of oxygen (doctors call this angina). And sometimes, even healthy young people can develop a condition called supraventricular tachycardia or SVT, where their heart can suddenly beat at close to 200 bpm without any particular reason at all – and yes this is an emergency which if untreated will lead to collapse or death.
Regarding exercise – your heart beats faster during exercise because your muscles release waste products that tell your body they need more oxygen, and the only way to get it there is by pumping more blood. So the heart pumps harder and faster. This mismatch between oxygen demand and supply is what makes you “fit”, and the waste products are the trigger for the heart to beat faster.
When you are fit, your muscles have adapted to use the same amount of oxygen more efficiently and therefore your heart does not need to pump as much fresh blood to meet the demands of the body. So for the majority of the time, your heart is actually quite relaxed. (There are other factors, such as exercise reducing resting blood pressure, which also contributes to long life.)
With stimulants, that is a different mechanism driving the increased heart rate, and there is no corresponding muscular adaptation occurring.
Its all about preload and afterload. Preload is the pressure that blood fills the heart and afterload is how much force the heart has to overcome, to push blood out.
When your exercising, preload increases and afterload decreases, which allows your heart to work at it’s most efficient. Like an athlete, lean, with great endurance.
Stimulants do the opposite to you preload and afterload, so the heart works harder and like a body builder it starts getting bigger with more muscle. Unfortunately the bigger muscle mass takes up space in your pumps (your ventricles) meaning that your heart uses more energy and moves less blood. So now it has to beat faster to move the same amount of blood than the leaner heart.
Why is this a problem? The heart beating faster against more pressure will wear out faster. The heart never stops beating, so unlike a body builder it can never take a break. If you ever see a bodybuilder run, they can’t keep up with a runner because they are heavier and use more energy, so they wear out faster
You are in a race that you can never stop running. So in this case, lean endurance beats strength.
Both things increase your heart rate, but they do it in very different ways.
When you’re doing cardio, your muscles are asking for more oxygen, so your brain signals your heart to circulate blood faster. Your blood vessels expand to support the increased blood flow, so even though your heart rate is high, your blood pressure is being managed properly. Also, if you’re running, the activity will help push the blood back up to your heart. Worst case, if you start feeling off, you can stop running or slow down, your muscles will need less oxygen, and your heart rate will slow back down, so there’s a nice feedback loop putting you in control.
On the other hand, stimulants increase the activity of the sympathetic nervous system-the “fight or flight” system, and increase the amount of stress hormone (adrenaline / noradrenaline) in your body (by either promoting production, or preventing reuptake). This makes your body think it’s in a high stress situation, and the increased presence of these hormones makes your heart beat faster. However, your muscles aren’t actually using more oxygen, so they don’t tell your arteries to expand to accommodate increased blood flow. In fact, the presence of adrenaline can actually cause blood vessels to constrict further. Also, since you’re not running / moving your legs, your heart has to push even harder to get the blood to circulate, as your leg muscles won’t help push it back up. So now your heart is pounding, your vessels aren’t ready to accommodate the increased flow causing blood pressure to rise, and on top of that, you don’t have an easy way to slow your heart rate back down (at least, not as easy as “just stop running”).
When you do cardio specifically, you challenge your system from the bottom-up, and the body can adjust to the new demands in a regulated way. When done regularly this leads to improved efficiency and therefore resilience of the cardiovascular system, as it adapts to the stressor. When you take stimulants, none of these adaptive/regularoty responses occur. Your body learns nothing and is only stressed.
Caffeine (redbull/ coffee/ energy drink/ supplements) can raise your blood pressure a ton. Toss in some salt (flaming hot Cheetos or French fries) and it can sky rocket.
Add some saturated fats and zero exercise and you have our current #1 killer of humans.
Heart disease.