• Quick note - the problem with Youtube videos not embedding on the forum appears to have been fixed, thanks to ZiprHead. If you do still see problems let me know.

Home Exercise Machines

Beady

Philosopher
Beady
Joined
Dec 14, 2003
Messages
6,886
Location
42d 45'23.3"N, 84d 35' 10.8'W, 840'>MSL
I guess this belongs here.

I've got an exercise bicycle that has one of those electronic consoles that gives you various statistics regarding your workout (distance traveled, calories burned, etc). Does anyone know how accurate these things are? I'm most interested in the calories/carbs burned in a session.
 
Machines that allow you to enter your weight are usually more accurate than ones that don't. The calories burned are based on an average weight (I think I read somewhere that the average weight used is around 150-175 pounds), so unless you fall somewhere in that range, it's not really accurate.
I know there are websites (fitday.com is one) that allow you to enter your weight, general fitness level and activity and it calculates your calories for you.
 
There are also other machines which not only allow you to enter your weight but also receive your HR from a chest belt transmitter you wear; these are supposed to be sufficiently accurate (there are some studies from the Polar pulse meters that show the calculations are rather accurate for practical purposes). The most common ones that don't allow any kind of user input are of course not accurate, but can still be useful as a relative indication of energy expenditure.
 
I've always been somewhat sceptical about these things.

It's easy to see how you could measure the external work done in exercise, but I doesn't see how they can account for all of the internal work, the adjustments your body has to make to itself to get the work done(how hard the heart has to pump, how heavily you breath etc.) and work done in recovery (what your body has to do to stop itself from hurting).

What makes it even harder to make an estimate is that these things don't just vary from person to person, but with practice as well. As you become accustomed to the exercise, these things get easier.

If someone could fill me in on how these estimates work, I'd appreciate it.
 
In this case I'd say it's safest to count results, not inputs. Weight loss, muscle strength, whatever your goal is -- progress toward that is something you can measure more reliably than the estimates you'll get in a consumer exercise gizzy.
 
The most accurate way is probably going to be a heart rate monitor, because it can actually measure how hard your heart is working. Comparing my Polar heart monitor to the treadmill at the gym, the numbers are nearly identical. The numbers on the elliptical machine are 30% more (for calories burned) than my HRM says. And I looked at the fitday site mentioned above. It was 50% less than my HRM says.
 
Heartrate and respiratory activity are probably the best measures of output. My wife had a stationary bike with a lot of this stuff on the console; I found the "speedometer" function to be wildy inaccurate.
Most cyclocomputers have some sort of calories-expended-per-workout function; I can't imagine that these things are very accurate. Just too many variables to input
 
I've seen metabolic measurements being taken in TV shows. As Bikewer mentions, respiration is a big part of it. The subject always seems to be wearing a mouthpiece/nose clip or a mask while tests are under way. [edit] ... connected to a CO2 measuring device, I'd think.
 
Meffy said:
I've seen metabolic measurements being taken in TV shows. As Bikewer mentions, respiration is a big part of it. The subject always seems to be wearing a mouthpiece/nose clip or a mask while tests are under way. [edit] ... connected to a CO2 measuring device, I'd think.
Click to expand...

If you are an athlete, that's a good measurement. For the home exerciser, a HRM should be accurate enough.
 
@Lisa: Long as there's an accurate way to map individual heart rates to calorie consumption, it ought to work.
 
Meffy said:
@Lisa: Long as there's an accurate way to map individual heart rates to calorie consumption, it ought to work.
Click to expand...

My HRM asked for my age, height, weight and sex. Even if the calorie calculations are not 100% exact for me specifically, I'm sure it's close enough based on other women my age, height, and weight.
 
My home exercise machine comes with no displays, no keyboards, darn it all. But it can throw up a marvelous rooster-tail of tilled earth! =^_^=
 
There's probably scales on the internet where you can look at your height, height, and measure your heatbeat to see what you're burning.
 
You must log in or register to reply here.

Back
Top Bottom