We are a commune of inquiring, skeptical, politically centrist, capitalist, anglophile, traditionalist New England Yankee humans, humanoids, and animals with many interests beyond and above politics. Each of us has had a high-school education (or GED), but all had ADD so didn't pay attention very well, especially the dogs. Each one of us does "try my best to be just like I am," and none of us enjoys working for others, including for Maggie, from whom we receive neither a nickel nor a dime. Freedom from nags, cranks, government, do-gooders, control-freaks and idiots is all that we ask for.
We post here frequently about the components of general fitness and physical training goals: strength, athleticism, power, endurance, etc. The variety of exercises that we recommend are stressing and training neuro-muscular and cardiac systems.
However, while we are stressing and challenging our bodies in all of the ways needed for balanced fitness, we are also training our metabolic energy systems for higher capactiy and efficiency. There is no need to know anything about it, but it is interesting.
It's basic high school biology. Animals (and plants) use ATP as an energy source for cellular functioning. ATP is generated and regenerated in the mitochondria.
However, our resting ATP batteries store very little reserve energy so 5- 20 seconds of high intensity, maximum anaerobic effort (eg 20-second sprints and HIIT sprints, or a set of heavy deadlifts) require instant regeneration of ATP. That's our "emergency" Phosphagen System. After depleted, it takes a couple of minutes to restore itself which is why you rest between deadlift sets or walk ("active recovery") between sprints. The Phosphagen system is trained by stressing it, but it has its limits.
After 10-20 seconds of high intensity, our cells turn to splitting sugar (mainly derived from carbs unless you have a Coke before exercise) - Glycolysis - to produce more ATP. This energy system, also requiring no oxygen, can keep us going for up to 2 minutes of intense effort. Like the Phosphagen system, Glycolysis is trained by short bursts of high intensity exertions of any sort.
A body can't live long, though, without oxygen. Both of the above are anaerobic (oxygen-independent) systems and neither can be sustained for very long without rest and oxygen to restore them. Aerobic exertion (using oxygen to burn sugars and fats - the Aerobic System -) can slowly but almost endlessly produce enough energy to maintain us during less intense activity in which we maintain a pretty good oxygen balance (or at rest, for that matter). Aerobic energy systems are trained and stressed by, say, 1-hour endurance exercises which keep the heart rate continuously well-above a walking heart rate, eg continuous calisthenics, and non-sprinting exercises like swimming speedy but not sprinting laps, treadmill intervals but not HIIT intervals, jogging, and similar exercises when you can breathe uncomfortably but effectively-enough to keep going.
Can aerobic exercise count as "cardio" exercise? Sort-of, maybe. It depends on where you keep your heart rate. High-intensity, high heart-rate bursts are the best heart-stressors and if it doesn't kill you it will make it stronger. Endurance is a different matter. Is normal walking "exercise"? Basically, no. It's just basic functioning unless it's fast and over 5 miles. "Cardio" means heart rate significantly elevated above walking.
Aerobic metabolism is highly efficient, which is why it takes 3 hours on an elliptical to burn the calories (270) in one plain bagel. It is why you can not lose weight by exercising unless you are fast- hiking 8 hrs/day on minimal caloric intake for a week or two. The average sedentary person (meaning under 5-10,000 "steps" daily with no other stressful exercise) probably needs less than 2000 calories per day to maintain their status quo. Remarkably, in the USA, it is not unusual for one single cheap meal to provide that much energy.In all of human history, remarkable indeed. Caloric abundance has a downside, thus the "overweight crisis" especially among our American poor.
A balanced fitness program (resistance, calisthenics, cardio, and endurance) ends up stressing all 3 energy systems without your having to think about it at all. That is just one of the many reasons why we endorse balanced fitness exercise programs instead of a single path (such as all weights, or all aerobics).
Funny now these numbers always wind up with lots of zeros on the end.
Like "10,000" steps being "ideal".
I guess when I hit 9,950 I should use my remaining 50 to get to bed?
You know what, f*king move. Don't sweat the numbers, just go. Go until you're breathing heavier and want to take a layer off, or unbutton something. Steps up or down a hill are better than steps on a plain, but even those are better than putting your feet up on the coffee table.
Also the difference between "aerobic" and "cardio" is about 15 years. In the 80s we talked about "aerobic fitness", then Richard Simmons popularized "Aerobisise" and that killed "aerobic exercise" for straight men.
By the late 1990s everyone called it "cardio".
William O. B'Livion
And as to:
> which is why it takes 3 hours on an elliptical to burn the calories (270) in one plain bagel
Now, I realize the counters on the machines can be off a *bit*, but back in 2003 I burned 720 calories in 35 minutes after hitting the elliptical 3-4 times a week for two 35 minute sessions (35 minutes, break for weight lifting, then another 35 minutes). I lost 20 pounds in 2 months with no dieting.
Then I stopped the exercise and my wife got pregnant and most of the fat came back. I'd moved to more weight lifting, so not all the fat came back, but most of it.
William O. B'Livion
Nice summary. Thanks.
And thanks for not saying "breaking the phosphate bond in ATP releases energy." Most people learn that in biology, and it takes years to correct it.
I've been reading from multiple sources that no one short of an elite athlete--think Lance Armstrong--really burns 700 calories in a single hour, let alone in 35 minutes, whatever the machines say. On the other hand, 90 calories an hour on an elliptical sounds low, too. I'd be interesting in a source for that. Nevertheless, I couldn't agree more that it's a rare person who can lose weight by increasing exercise without significantly cutting calories.
My maintenance calories intake (I'm 5'5" and not particularly active) is about 1200-1300 a day. It's amazing to me how much I used to eat. I've been at this new lower level for a little over a year now. It's beginning to seem normal.