Why Do Athletes Have A Lower Resting Pulse?

 

I’ve only another week or so studying and I’m back full time at A1 for a few months for 4 or 5 months.

It’s been a slog but I can safely say I can see the light.

I had a conversation with an exercise physiologist a few days ago about my full time days and in particular the mistakes I made with training.

‘It wasn’t all my fault’ I thought in my head, ‘I had a coach’.

We talked about how knowledge and awareness of what goes on in your body when you exercise and what happens as a result of that exercise has a profound effect on your ability to train optimally.

I used to believe I knew my body better than anyone – I was completely wrong.

Again I was very aware when something just wasn’t right and on the contrary when everything was just right.

But – I didn’t know WHY?

That’s what I’m interested in.

The more you know about your body the better you are at interpreting what it needs.

Instead of blogging about something unrelated and task switching to an unrelated topic I’m going to give you a bit of an exercise physiology lecture.

And I’ve a challenge for you guys!

Can you tell why our heartrate increases when you exercise?

Secondly, can you tell me why an athlete or trained individual exhibits a lower resting pulse than the average untrained chap?

I’ll buy you a coffee if you can!

Ok let’s begin with our pulse rising in response to exercise.

 

Nervous systems

We have all heard of our nervous system.

Well this is the ‘big dog’ player in your heartrates response whether it’s speeding up or slowing down.

What a lot of people don’t know is that our nervous system can be further broken down into its respective divisions.

Firstly we have our central and peripheral nervous system.

Our central nervous system is comprised of our brain and spinal cord while our peripheral system has a sensory and motor component.

In lay man’s terms our peripheral system senses something – ‘shit that’s hot!’

Takes this to the central nervous system- via afferent nerves, where a response is propagated

Which is then sent back to the periphery via efferent nerves to initiate an action.

‘Take your fucking hand off the hob!’

 

Peripheral nervous system and the motor division

We are interested in the motor division of your peripheral nervous system.

You see this motor division brakes down a little further into your autonomic and somatic divisions or in other words automatic and manual divisions.

You see there 100’s of processes going on in your body at this very second that are not under your conscious control.

Breathing, digestion, blinking and your heart beating are all examples!

This is thanks to your autonomic nervous system.

On the flip side, you do have control over your skeletal muscle (e.g. Your quads) and when you contract them, this is taken care of by the somatic or ‘manual’ division.

 

The important bit

Let’s refer back to our initial questions.

Why does your heartrate rise when you exercise and why its resting value is reduced as a result of training.

I propose a question, do you think you have any control over these resultant factors?

That’s right, no you don’t.

So what causes the autonomic nervous system to speed up and slow down your heartrate?

 

Sympathetic and parasympathetic divisions 

These are the final two divisions, I promise!

When your pulse speeds up it’s because of sympathetic stimulation.

The stimulation results in a cascade of effects that result in the release of two very important biochemicals – Epinephrine and norepinephrine.

In other words – adrenaline!

After a further number of biochemical processes that don’t need to be mentioned here – more sodium and Calcium is released into the hearts pacemaker cells.

This is crucial!

Calcium and sodium cause the heart to depolarise and subsequently contract once their values reach a particular level!

Thus if there’s more of these two bio-chemicals – it depolarises and beats faster!

Not only does it beat faster it beats more forcefully!

More force means more blood is pumped out of the heart – great news.

 

The training effect

Ok so why have I got a resting pulse in the low 30’s?

Apart from being an oddball that is.

This is because of parasympathetic stimulation.

As a result of exercise there is increased firing of parasympathetic nerves at rest.

Something the science boffins call – ‘vagal tone’.

Similarly the parasympathetic activity causes a cascade of biochemical processes but this time it’s not adrenaline that’s released – it’s a biochemical called acetylcholine.

Acetylcholine initiates the reduction of sodium and calcium getting into the cell so heartrate is reduced!

Acetylcholine also exacerbates the release of potassium into the cell and potassium does the opposite to calcium and sodium.

Its repolarises the cell which means the pacemaker cells are brought further away from the point where they contract – in other words – to contract, the sodium and calcium need to start building from a lower point!

The one word answer you’re looking for to why an athlete’s heartrate is lower at rest is because they possess more circulating acetylcholine at rest.

Anyway that’s enough science for one day!

A. Buggle

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