# Heart rate and getting stronger - cardio-vascular changes...?



## wafter (1 Jun 2020)

Please bear with me as physiology's certainly not my strong point..

Heart rate is a good measure of physical exertion as it correlates with blood volume flow rate, which is proportional to oxygen supply to the muscles. As I understand it max heart rate is broadly fixed for an individual based on physical factors and age.

I also understand that as strength improves through exercise your muscles grow, allowing them to exert more force, hence burn more energy /and equre more oxygen.

So, as you become fitter / stronger you're able to produce more power throughout the same heart rate range. Assuming that the heart always provides an appropriate amount of blood to the muscles, what cardio-vascular changes occur as fitness improves to cater for the increased oxygen demand from the muscles, since the heart is still beating at the same rate?

I'm thinking maybe:
- Increase in blood oxygen concentration
- Enlarged arteries and veins
- Enlarged heart?
- More efficient heart function?
- Enlarged lungs?
- More efficient lung function?

I'm guessing that organ growth can only account for a small amount of improvement (if at all) since they can't grow proportionally to the strength that can be gained through training (twice the strengh doesn't mean twice the lung volume).

Would be interested to learn more if anyone knows or has any good links, ta


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## fossyant (1 Jun 2020)

So what answer do you want ? Work harder, get fitter.


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## wafter (1 Jun 2020)

fossyant said:


> So what answer do you want ? Work harder, get fitter.


Preferably something a little more explanatory than your offering


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## wafter (1 Jun 2020)

Anyway, thanks to BBC bitesize I have an answer of appropriate resolution EDIT: that should at least serve to seed a bit more digging 

Interesting point about cardiac hypertrophy and resting heart rate - never thought of the reason behind why your resting HR falls as you get fitter.

Glad I don't have to re-take my GCSEs..

EDIT 2: A good overview of changes to the respiritory system here.


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## MrGrumpy (4 Jun 2020)

wafter said:


> Interesting point about cardiac hypertrophy and resting heart rate - never thought of the reason behind why your resting HR falls as you get fitter.
> 
> 
> 
> EDIT 2: A good overview of changes to the respiritory system here.



Funny my resting HR has not changed a huge amount since my late teens, early twenties. Used to sit below 40 -now sits about 46-48. I can only put that down to being quite active all my adult life.


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## Ian H (4 Jun 2020)

I believe the main signifiers, in terms of heart function, of increased fitness are: reduced heart-rate for given exertion; increased range low to high; quicker return towards resting rate after exertion.


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## T.M.H.N.E.T (4 Jun 2020)

Ian H said:


> I believe the main signifiers, in terms of heart function, of increased fitness are: reduced heart-rate for given exertion; increased range low to high; quicker return towards resting rate after exertion.


Pretty much


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## PaulSB (4 Jun 2020)

Ian H said:


> I believe the main signifiers, in terms of heart function, of increased fitness are: reduced heart-rate for given exertion; increased range low to high; quicker return towards resting rate after exertion.


Yep, that's my experience. I had a heart attack 4-5 years ago - the doctor came to me and asked "Is your heart rate always this low? We dare not give you beta blockers!"

I'm sure HR is interesting but feel overall fitness is more important. I've had two very close brushes with death. Both times the medical staff have been amazed by my recovery. Each time I was told my high fitness level was the reason. Last time I recovered in 3 months with the norm being 18.


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## Ming the Merciless (29 Jun 2020)

Here you go, have a read of this 

https://physiologicalresponsestotraining.weebly.com/introduction.html


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## hbeevers (30 Jun 2020)

> what cardio-vascular changes occur as fitness improves to cater for the increased oxygen demand from the muscles, since the heart is still beating at the same rate?



Just some reasons, there are many:

Increased lung capacity, more surface area from alveoli.
Increased blood oxygen capacity, more haemoglobin
Increased transfer of oxygen from lungs to blood to muscles. Due to increased capillary beds.
Interestingly, and I only found this out recently having been taught the classic lactic acid (lactate) is bad at uni, lactic acid is actually utilized by muscles rather than having a dampening effect. Lactate shuttle theory. You're able to more efficiently utilize lactic acid as you get fitter.
Muscle changes such as slow:fast twitch ratio improving aerobic efficiency or fast power production (endurance vs sprint).
Endurance training at aerobic levels increases fat over carb burning for energy. This means your immediate carb energy store in the muscles ,~1200 calories i think, effectively goes further.

Really good article here if you're interested:
https://www.uphillathlete.com/why-you-are-forced-to-slow-down/


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## wafter (1 Jul 2020)

YukonBoy said:


> Here you go, have a read of this
> 
> https://physiologicalresponsestotraining.weebly.com/introduction.html


Thanks - about halfway through the site and it seems to provide a decent overview of all I was looking for 



hbeevers said:


> Just some reasons, there are many:
> 
> Increased lung capacity, more surface area from alveoli.
> Increased blood oxygen capacity, more haemoglobin
> ...


Cheers! 

Interesting point about the lactic acid; less of an issue for me however as I appear mostly allergic to going hard for any length of time


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