Monday, September 18, 2006

Fun Fitness Facts

Ok, so I'm doing some reasearch on calorie burn for guys my size; and I found some interesting things out about what activities burn how many calories (per hour over baseline). Here's a sampling of the activities I actually do, calibrated for a 440lb man:
  • Baseline activity: 200
  • Walking the dog: 690
  • Playing Darts: 500
  • Shooting (stationary): 700
  • Shooting (action): 990
  • Recreational Bicycling: 795
  • Excercyling (moderate to heavy): 1450
  • Calisthenics: 1590
  • Circuit Training: 1600
  • Weight Lifting: 1200
  • Car repair: 600
  • Construction/building/home repair: 1090
  • Cooking (sustained activity): 500
  • Cleaning (vigorous): 900
  • Playing with the kids (vigorously): 989
Well, that's a lot of calories being burned, for mostly normal every day activites; why is that?

Simple; again it's thermodynamics. It takes energy to move, energy to breathe, energy to make your heart beat, and energy to maintain your body temperature.

The calorie is a measurement of energy; in particular, the amount of heat energy required to raise the temperature of one gram of water, one degree centigrade; which works out to 16 calories per ounce per degree farenheit, or 256 calories per pound per degree farenheit; and assuming a 72 degree room temperature, and a 98 degree body temperature, you would need 6656 calories per pound to reach body temp.

Wait a sec, 6656 calories per pound? a 440 pound man would need 3 MILLION calories an hour just to maintain body temperature.

Well, obviously that's wrong, and there's a couple of reasons for that. One, human beings are about 80% water, not 100%, and it takes varying amounts of energy for most of the other substances to be raised a degree.

Two, it doesn't take that many calories constantly to MAINTAIN temperature once it's achieved. Human beings have a fairly low area to mass ratio; so we disapate heat rather slowly (between 1 and 2 degrees per hour given normal clothing,and assuming a 72 degree room temperature).

Finally three, what people think of calories arent actually calories; they're kilocalories (1000 calories). In food terms, almsot everything is listed as kcal, but shown as cal.

No, it doesnt make sense, it's jsut the way they do it.

Anyway, if I were 100 percent water, it would take about 195 Kcalories an hour, just to maintain my body temperature (presuming a 72 degree room); or about 4,680 Kcalories a day.

In reality, we are not 100% water; and of course it takes more than jsut maintaining body temperature to survive, so as I said before, most folks burn somewhere around 11 calories (actually KCal) per pound per day; which in my case works out to about 4,840 KCal per day, or about 202 calories per hour (actually it's more like 225 calories per waking hour, and 150 calories per resting hour)

Okay, anyway, the point is that calorie burn for a given level of activity is directly proportional to the mass of the person burning it. If it takes a given amount of energy to move a given muscle one meter under 200lbs load, it will take about twice that energy for a 4oolb load assuming everything reminad constant.

So those activities that look like "not much work" to someone who only weights 150lbs, burn a HELL of a lot more calories for someone who's 440.

Of course this advantage goes away (hopefully) quickly as you lose weight; but at the moment I've got about a 2.6 to 1 calorie burning advantage for everything I do; over a 170lb "standard" man.

Obviously this doenst always apply to all activities, for one thing mass isn't distributed uniformly, and neither is the load imposed by a given excercise; but for estimation purposes these things are taken as uniform averages.

Hell, food calories are really jsut a rough guess anyway, because every pice of chicken, or cheese that you eat will have slightly different values. On the other side of ocurse, every step you walk is different from every previous step, even if it is by a fraction of a percent.

Honestly NO excercise is effective in causing weight loss, unless it results in a sustained increase of heart rate and body temperature of more than 20 minutes. Oh sure theres a change, but not very much. The 20 minute mark is about where the body says "Oh hey, this is for real; we arent jsut running froma bear or something" and the weight loss, and fitness effects kick in.

These estimates are jsut taht. estimates. They are scientific, but that doesnt mean they are any mroe accurate, because all they are doing is averaging things out, between people, axtivities, temperatures, difficulites etc...

What fitness and weight loss excercise comes down to, is raising your heart rate, and raising your temperature. Any excercise that gets your heart rate up to 80% of peak ideal rate (220 beats per minute minus your age) for at least 20 minutes, will burn 3-5 times your basal rate depending on your fitness level (the body temp will go up 2 degreees or so, and the heart rate will double or triple); no matter what it is. If you are a 30 year old, 440lb man; and walking the dog gets your heart rate up to 155 (it doesnt for me, this is jsut an example), and your temperature up to 101, then you'll burn 2500 calories walking the dog (vs the 690 estimated above).

I dunno about y'all, but I find this stuff fascinating.