What is fitness?

[geomannie]

I was out for a run today, feeling good and going better than usual, and got to wondering what exactly is fitness; what are the physiological changes that the body undergoes in becoming aerobically fit? Is it simply the strengthening of the heart muscle or are other changes involved, such as the way the body becomes able to metabolise energy such as that stored as glycogen. As a secondary question, I got to wondering, if fitness is so good for us, why have we not evolved as a species to be always “fit”, why do we have to exercise to attain and maintain it?

While the questions are simple, I am sure that the answers will be complex. Any biologists out there?

[NATURAL ANKLING]

Hi,
No Ologest (Ology)

But long time ago we would of acted like animals to survive.........fittest........

If you had to run after your food you would.

[Tangled Metal]

We're a mostly sedentary species here. Even a couple of generations ago we'd have been working harder in more physically demanding jobs. We'd also be eating less processed foods a few generations back. All adds up.

BTW there's unlikely to be any mammal that's evolved to n be fit. They're evolved for the way they live, such as the way they get their food impacts on what physical characteristics they need and have. It's probably just that we have evolved a brain capable of developing tools and making life easier. It has progressed too far resulting in our species needing to cut back on consumption and increase activity. That's partly leisure because of our efficiencies. It ultimately leads to the need for carrying out activities reminiscent of our food gathering past just.to get and stay fit. Running, jumping, etc.

Take a look at fat pets. They're like that because consumption exceeds need. They need to get fitter too. It's a mammalian thing and mostly in unnatural circumstances.

[mercalia]

fitness is fit for purpose?

[landsurfer]

fitness is fit for purpose?

+1 And a lot more .... There have been articles in the press recently stating that "Fat and Fit " is a myth.

"Fat" is about body weight, social standards and "Image" as seen in the fitness and fashion press ....

If you are 185cm tall and 90kg and can comfortably ride a 100 mile sportive in 6 hours .. you are regarded as fit.
If you are 185cm tall and 125kg and can comfortably ride a 100 mile sportive in 6 hours .. you are regarded as obese.

Do we need to re-define "FIT" ?

[keyboardmonkey]

"Fitness means suitability, and I find my body very well suited to sitting down on its bottom a lot and to lifting coffee-cups and pressing lift buttons."

Stephen Fry, The Listener, May 26, 1988.

[geomannie]

Thanks for your thoughts folks, but what I am wondering about are the physiological changes that occur with aeorbic training. For example, consider if I exercised hard for the next 6 months or I sat on the couch for the next 6 months, but eating a diet that meant my weight were the same as if I had exercised. If a skilled anatomist were to examine and analyse my body (in both cases) after the 6 months, what diferences would they find: in the exercised veriosn of me, a larger stronger heart?, more efficient O2 input, better burning of calories.......what????

[landsurfer]

All good points...
But this a touring cycling site ..
We tour ... often huge milages ....
A lot of the issues you raise are about intense, high level, cycle racing ... TT , hill climb or road race ...
But this a touring cycling site ..
Maybe our focus is in a different direction ....?

Personally, i am recovering from a bad knee .... not ridden much in the last month, but ready to get back on my bike.
I am a partial "MAMIL".
Bib shorts, Look / KEO shoes, baggy "old guys rule" cycling t shirts ... and track mitts ...
I aim to ride lots of miles and enjoy the view ....
But it often turns into a personal time trial .....

[Mick F]

People hereabouts are aware of my regular cycling and the mileages I do and the hills I climb.
They say, "You must be very fit!"

I reply that I don't really think about fitness, but add that I like cycling because it keeps me sane, and that fitness is a bi-product.

[Paulatic]

Fitness is a feel good factor your body enjoys.
Personally I hate it when I become overly fit, a few short fast rides or a few hard games of squash in a week then I suffer with Bradycardia. Then getting up out of the chair is not something to look forward to. Being a couch potato then looks attractive or inevitable.

[Tangled Metal]

For me fitness is about being able to do things because your body is working well. I'm fit enough to enjoy walking up that Lakeland fell without collapsing in a heap. Or to ride with the family and not worry about the hills even though I'm towing a youngster behind me. Or that I still feel good after commuting into work through the nightmare of heavy rain and strong winds.

It's partly my body is fit for purpose. It's also that the process of getting and maintaining this fitness for purpose is likely to keep me alive longer and in a state to enjoy that extra lifespan. Add in that in enjoy the process because it's basically me doing what I like. Whether walking, cycling, backpacking, cycle touring, kayaking, etc. I'm having fun and staying fit for purpose.

Not sure this answers tyre OPs original query but it's kind of my understanding.

[david7591]

fitness is fit for purpose?

So if your purpose is to watch tv 24/7 whilst eating fast food, then being fit could be being grossly overweight and barely able to walk a few steps

[david7591]

How about the ability to exercise at high percentage of maximum heart rate for a prolonged period of time without build up of lactic acid. Having a maximum heart rate higher than the norm for your age, and a low resting rate. Ability to recover quickly from strenuous exercise. Efficient oxygen delivery to working muscles. These are all characteristics of a fit person, how they manifest themselves physically in the body, I wouldn't know.

[Tigerbiten]

Thanks for your thoughts folks, but what I am wondering about are the physiological changes that occur with aerobic training. For example, consider if I exercised hard for the next 6 months or I sat on the couch for the next 6 months, but eating a diet that meant my weight were the same as if I had exercised. If a skilled anatomist were to examine and analyse my body (in both cases) after the 6 months, what differences would they find: in the exercised version of me, a larger stronger heart?, more efficient O2 input, better burning of calories.......what????

Macroscopic you could not tell much difference just by looking.
Microscopic there will be difference in the fast vs slow twitch muscles, VO2 max, heart rate, etc.

One thing I find on long tours is that you soon get acclimatized to the level of output needed. I could do 60 miles a day, day in day out, on the flat no problem. But as soon as I hit the hills, I needed a whole new level of fitness.

[trilathon]

mitochrondial density( RNA cellular power houses ), appropriate muscle size, fibre type and density, bone density, low subcutaneous fat level, more red blood cells to carry the oxygen via haemoglobin, vascullar system density and effciciency, metabollic effciency at a specific task , intensity and duration, flexibilty of tendons and range of movement appropriate to sport, a modicom of mental toughness for the task in hand...off the top of my head.

So ideally massive lung surface area for O2 gaseous exchange, tons of red blood cells to carry the Oxygen to the muscles, efficient and appropriate muscles and fibres specific to the sport and intensity, low fat levels so you are not hulking lots of useless heavy fat about, once inside the muscle you want genetic disposition and training stimuli to over years to produce lots of mitchrondria to produce the contractions and power, and effcicient dense capillary system to deliver and get rid of products and a mind that can tune , learn and apadt through a scientific methodology so that you can tailor the training , stimuli and response to your own metabollic talents....fitness is obtained through systematic specific overload and appropriate recovery, you use it or lose it.

I compete and tour, touring is harder in my book , requiring a lot more ...most events are but few minutes to a few hours whilst a tour has ( mostly lower level intensity but not always) , but greater duration and you look after your sen and make the choices and aren't mollycoddled with tape and drinks stations and prepared routes,prizes, social status and the like. Intrinsic and extrinsic satisfaction.