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Author Topic: Does exercise lead to a bigger heart?  (Read 10697 times)

Offline thedoc

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Does exercise lead to a bigger heart?
« on: 19/09/2013 08:13:57 »
I was wondering about the fibres in the muscle of the heart.  I understand that most muscles in the rest of our body become thicker and bigger as a response to intense workout such as lifting weights or anything like that, but when we do cardio intensive workouts, does that lead to  the same response? Does that create a physically bigger heart?
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« Last Edit: 19/09/2013 08:13:57 by _system »


 

Offline RD

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Re: Why doesn't the heart get tired?
« Reply #1 on: 12/03/2012 21:59:03 »
 

Offline Nizzle

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Re: Why doesn't the heart get tired?
« Reply #2 on: 15/03/2012 14:42:51 »
The heart does infact get tired.
It only takes about a century (+/- 30 years or so, depending on the individual)...

A lot of people that died of old age while being in perfect health died because their heart was tired.
 

Offline Lmnre

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Re: Why doesn't the heart get tired?
« Reply #3 on: 15/03/2012 15:16:38 »
Since the human heart is a muscle, why doesn't it get sore from intense exercise such as conditioning?
Sore. Yes, cardiac muscles are highly resistant to fatigue, and do not so easily fatigue as skeletal muscles, yet they do undergo stress that causes them to grow in order to pump higher volumes (usually in response to aerobic exercise) or to pump higher pressures (usually in response to anaerobic exercise). 

So, when we exercise so much, either aerobically or anaerobically, that causes the heart to grow, why don't we feel "sore" in our hearts? I would say that everyone would admit that their hearts feel perfectly fine, even when the rest of their bodies are exhausted, except when they're having heart attacks or something similar (angina pectoris).

I think the answer involves the "referred pain" one feels when suffering a heart attack and other disorders (including "ice cream headaches"). Classically, heart attacks are "felt" in the upper left section of the body -- left shoulder, left arm, left side of the jaw -- and also the neck, shoulders and back. My guess would be that a sore heart caused by exercise might feel like it's coming from these areas and not from the center of your torso where the heart is actually located.
 

Offline cheryl j

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Re: Why doesn't the heart get tired?
« Reply #4 on: 15/03/2012 16:17:33 »
I'm not completely sure why the heart muscle wouldnt be sore after exercise. With skeletal muscles, the soreness after exercise is the result of lactic acid build up, and inflammation resulting from microscopic tears in muscle fibres. Inflammatory chemicals released from damaged cells stimulate pain receptors in skeletal muscles So the question would be, does the same kind of inflammation happen in the heart and does the heart have any pain receptors that are sensitive to inflammation? Or do pain receptors in the heart only respond to being severely deprived of oxygen?

 According to an e-medicine article, angina or pain caused by ischemia is the result of  ATP being degraded to "adenosine, which, after diffusion to the extracellular space, causes arteriolar dilation and anginal pain. Adenosine induces angina mainly by stimulating the A1 receptors in cardiac afferent nerve endings." Unless you  already have heart disease, I doubt you could exercise to the point of inducing angina in a healthy heart, because blood would be shunted away from your arms and legs first and make you stop.

Both exercise, and oxygen depletion due to disease, cause the heart muscle to enlarge. But hypertrophy due to exercise results in more muscle mass and stronger contractions or  pumping ability. Enlargement due to disease results in more collagen or scar tissue, which doesnt increase the force of contractions, but does increase the volume of blood being pumped out somewhat, simply because the heart is now a larger container.

But the heart truly is an amazing muscle. It pumps about 7,600 liters a day, non-stop.
« Last Edit: 15/03/2012 16:22:38 by cheryl j »
 

Offline Airthumbs

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Re: Why doesn't the heart get tired?
« Reply #5 on: 16/03/2012 22:51:26 »
I think that when your heart is fatigued although it is not felt directly the symptoms are exhibited elsewhere throughout the body both physically and mentally.  Personal experience has demonstrated that as I had a long standing un-diagnosed heart problem and was diagnosed as having extreme muscle fatigue in my left ventricle.  I can only say that leading up to the chance discovery of a problem, I was not feeling right! I was more stressed for no particular reason and would get tired quickly for no reason. 

Can the health of our heart effect our emotions?  Maybe it's not the heart that gets tired, it's us!
 

Offline RD

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Re: Why doesn't the heart get tired?
« Reply #6 on: 21/03/2012 14:48:44 »
But the heart truly is an amazing muscle. It pumps about 7,600 liters a day, non-stop.

"non-stop" is misleading, an individual heat muscle will be at rest for part (most?) of the duty cycle.
 

Offline Domnomnom

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Re: Why doesn't the heart get tired?
« Reply #7 on: 22/03/2012 08:45:36 »
A couple reasons.

Cardiac muscle is ~70% Mitochondria by volume, where as skeletal muscle is around 5%. This makes a tremendous difference.

The heart is only a short coronary artery away from oxygenated blood. No problem with aerobic respiration.

Quote
"non-stop" is misleading, an individual heat muscle will be at rest for part (most?) of the duty cycle.
It isn't really misleading to say such. Resting is part of the pump, allowing it to fill. If a heart was in constant contraction, no blood would flow through it.
 

Offline evan_au

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Re: Does exercise lead to a bigger heart?
« Reply #8 on: 15/11/2012 10:53:07 »
There is a series of medical conditions which result in an enlarged heart, because the heart is having trouble pumping blood around the body, and this struggle goes on 24 hours per day.

This should not be confused with healthy exercise where the heart and the blood vessels cooperate and grow as a result of exercise so they pump blood more easily around the body. As soon as the vigorous exercise is finished, the heart rate and blood pressure drops, usually below the level of a sedentary person.
 

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Re: Does exercise lead to a bigger heart?
« Reply #8 on: 15/11/2012 10:53:07 »

 

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