Friday 2 February 2007

Fitness Basics for Couch Potatoes

Posted by speedygeoff on Friday, February 02, 2007 with
Newspaper Headline of the day: "Red Tape Holds Up New Bridge"

We live in a world charactised by the Audience and Spectator Mentality. Few are in the arena; most are in the stands. But even with a great event like the A-Series Athletics Meet which was on recently, I was quite happy about missing it and doing other things. I would much rather be the performer than be the audience.

Sometimes I forget that most people don't know the basics of why action is better than observation!

"Why can a trained athlete run a marathon, but a couch potato cannot run half a mile?" - from http://www.howstuffworks.com:

If you are out of shape, you know it. Even climbing a flight of stairs can leave you out of breath! If you haven't been exercising regularly, even a little exercise, like going up steps, can put a strain on your body.

Your body responds to exercise with a coordinated effort from many systems, including working muscles, the heart, lungs, blood vessels, skin, brain and others. Here are what the different parts of your body do when you exercise:

The muscles provide the strength, power, and endurance to do the exercise.
Enzymes within the muscles mobilize various fuels to provide ATP to meet the energy demands of working muscle.
The heart and blood vessels increase the blood flow to deliver more oxygen to the working muscle.
The lungs increase the rate of breathing to deliver more oxygen to the muscle.

All of these systems can be improved by training. Lack of training causes them to atrophy.

Let's compare the couch potato with the trained athlete. The couch potato has these problems:
weakened or atrophied muscles
weakened or atrophied heart muscle
decreased metabolic enzymes in the muscles
diminished lung capacity
the wrong metabolic fuels


If muscles are not used regularly, then their mass decreases. The muscle proteins and fibers that develop the force diminish. Therefore, the couch potato simply cannot generate the force required for the physical activity involved in running a marathon.

The heart is a muscle like skeletal muscle. It also adapts to a less active state by losing muscle mass. While this does not affect the couch potato's ability to pump blood to his/her tissues, it limits the ability to increase in blood flow during exercise. The heart will not be able to stretch as far or develop the pressure required to increase the cardiac output. That's why doctors tell you that you need to exercise regularly to keep your heart in shape.

The enzymes involved in anaerobic (without oxygen) and aerobic (with oxygen) metabolism help provide the energy to working muscle. In the couch potato, however, the levels of these enzymes go down. So the inactive person's body cannot metabolize fuel as well.

The fuels used in the body during exercise mainly come from carbohydrates (glucose, muscle glycogen) and some fat. However, the couch potato has mostly fat and probably little glycogen. It takes longer to mobilize fat as a fuel than glycogen. That means that the breakdown of fat cannot keep pace with the energy demands of working muscle.

All of these factors combine to limit the ability of the couch potato to exercise.

The good news is that, with a moderate exercise program, the couch potato or anyone else can improve their fitness and their body's response to exercise. At least enough to do a 10 km run!







FOOTNOTES
1. At track last night, strong performances by Ken and Katie in the 3000m, with Ken getting under 12 mins for the first time this season, ~11:47; and Katie improving her pb by ~20 seconds and breaking 12 mins for the first time, ~11:55. In the 5000m, a good run by Amanda to knock ~10secs or so from her pb [edit: the "or so" is 50 seconds. It was a 1 minute pb, Awesome! Sorry to devalue it!], running ~21:32; Ewen achieving a bet-motivated goal and ducking under 23 mins. And I ran ~19:27, getting well under the 20min barrier in my first real attempt since last April, with splits of 3:50, 3:49, 3:57, 3:56 and 3:55. This equals my time in the Nationals last year. And means I still might get that sub 40 10k; the next challenge.

2. And the W45 4x1500m relay team set an Australian record last night; the team included Helen and Maria, both running just under six minutes.

3. Soon I will have a go at my first “new-blogger” html hacks for this blog, which will be to try and re-introduce peek-a-boo comments as were in the previous version. Once that is done, the plan is to change to an inline form for comment creation, and after that I will try asynchronous peek-a-boo comments, if I think they are needed. These changes involve a fair bit of html. I may do it this afternoon if the cricket is slow and if I haven't fallen asleep on the couch. And after all that is implemented, I will see what I can do about colour scheme and general appearance.

not speedy