Rage Against the Elliptical Machine
October 5, 2009 10:57 AM   Subscribe

What am I not getting about the elliptical machine at the gym?

I've recently started going to the gym, and I've fallen in love with the elliptical machines. Even on days when I don't feel like working out, I can at least find the strength to spend some time with the ellipticals. Unfortunately, I'm not sure that I understand what they're doing.

I normally do about 45 minutes on the machine. I don't flat-out jam, but I keep a pace that I think is pretty respectable. According to the computer screen for the machines, my 45 minute "run" (plus the 5 minute cool-down) burns around 650 calories. It's not just one machine that tells me this; they all give roughly the same result.

This sounds great to me, but whenever I've mentioned it to friends, they tell me that it's flat-out impossible that I'm burning that many calories during a 45 minute elliptical session (they've suggested that it's probably closer to 300 calories). Are they right? If so, what is happening that's causing the incorrect reading on the elliptical machine's computer, and how can I get a more accurate picture of how many calories I'm burning?
posted by Parasite Unseen to Health & Fitness (25 answers total) 9 users marked this as a favorite
The machine is never going to tell you exactly how many calories you're burning. It has no way of accurately knowing the variables it would need to make that calculation (sure, you can plug in your weight and height, but even then there are other factors, like your metabolism, at play). So, it's not an "incorrect" result as such, except in that all results from such machines are inherently incorrect.
posted by ocherdraco at 11:02 AM on October 5, 2009 [1 favorite]

I agree--that 650 calories seems blissfully high. I don't have an explanation, but all the ellipticals I've ever used suggest I am burning more calories with even only a moderate workout than reflected on a treadmill at a "ohmigod I am a sweaty beast in the final throes following a deathsprint."
posted by Admiral Haddock at 11:06 AM on October 5, 2009

Also: the makers of the machines may feel they have a vested interest in telling you you've burned more calories than you actually have, so that you'll be more inclined to use their machines, which will in turn make your gym more likely to order machines from them the next time around.
posted by ocherdraco at 11:08 AM on October 5, 2009 [2 favorites]

What kinda heart rate are you getting to? Do you know? Could you stop for a minute and check? I'm in pretty damn good shape (ten pounds more than I'd like, but a rest pulse of 48), and an hour's hard run - 8:30 per mile - bumps me out at about 775 cal. If you're just cruisin', and only 45 minutes, your number sounds high.
posted by notsnot at 11:10 AM on October 5, 2009

My friend weighs 300 pounds and "burns" about 400 calories on the elliptical for 30 minutes. I weigh 170 pounds and burn only about 230 or so. The machine knows the difference because we have entered our weights into the machine. If there's more of you to burn, then that's what happens. 650 is conceivable for an overweight person doing 45 minutes, but yeah, it does seem to be a bit of a stretch.
posted by Melismata at 11:11 AM on October 5, 2009

This article cites a couple of people who say that ellipticals "allows the user to burn roughly the same amount of calories as treadmills with the impression of putting CONSIDERABLY less effort." I'm not sure what the unit of comparison is here (time or distance), but even so, although the part about less effort suggests you may be working harder than you think, the rest suggests you aren't burning 650 calories. Running burns roughly 100 calories/mile, with the difference in speed meaning that you burn more calories per unit of time the faster you run. This suggests that your workout is the equivalent of running ~6.25 miles in 45 minutes. I'm not sure what kind of shape you're in, but this would be a strenuous workout for most recreational runners. It seems a bit implausible (given the casual tone of the exercise described in your question) that you would be working comparably hard on the elliptical even given the differences in perceived effort.

Googling "are ellipticals better than treadmills" gives a slew of results.
posted by OmieWise at 11:21 AM on October 5, 2009 [1 favorite]

Ellipticals are pretty notorious for overestimating how many calories you've burned on them. I use the calories-burned counter only as a relative measure of how hard I've been working out - e.g. if I'm on the machine the same amount of time as yesterday but burned 25 more calories, I'm probably doing pretty good.

The number will be even less accurate if you're using poor form, like leaning on the handles or bouncing around too much. If you stand up straight and keep your upper body relatively still, you'll get a more challenging workout.
posted by Metroid Baby at 11:24 AM on October 5, 2009 [1 favorite]

According to a study cited on this page, most elliptical machines over-estimate calories by 10-30%. I wasn't able to find the actual study.

Here is a related study from the Naval Health Research Center. Their conclusion was: "Machine calorie reports were strongly related to measured energy expenditure. The slope of the pooled regression line was not significantly different from 1.00. The machine calorie reports were higher than the measured energy expenditures for all three machines. The magnitude of bias differed between machines."
posted by blue_beetle at 11:25 AM on October 5, 2009

You should note though, that last study I referenced concluded: "All three [Elliptical Trainer] models provided valid, but biased, reports of energy expenditure...All of the biases are too small to be important when the machines are used to monitor long-term energy expenditure as part of a regular exercise program"
posted by blue_beetle at 11:26 AM on October 5, 2009

I've been wondering about this too. There are two brands of ellipticals at our gym, and they vary wildly in their estimates. With the same weight and setting, one says I'm burning 750 calories (!) in 40 minutes, the other says I'm burning 400 calories in 40 minutes. I believe the latter over the former, but it's pretty likely I'm actually burning around 300, as your friends suggest. It's amazing to me how these machines can be so flagrantly wrong about their calorie estimates.
posted by naju at 11:47 AM on October 5, 2009

The very point of an elliptical is to remove from a cardio workout all the sources of perceived exertion which are not in fact burning calories: the foot / knee / hip / back strain of the treadmill, and the knee / back strain of the bike. Thus the apparent effect of more calories per unit of pain.

In my gym, one set of ellipticals is pretty darn borked -- a big guy's vigorous hour session can read 1200 calories easy, with another set of elliptical reading under 900 calories for the same session.
posted by MattD at 12:04 PM on October 5, 2009

Response by poster: My friend weighs 300 pounds and "burns" about 400 calories on the elliptical for 30 minutes. I weigh 170 pounds and burn only about 230 or so.

I'm 6'6", and somewhere in the neighborhood of 255 pounds. So, I'm overweight (I'm fortunate that my height lets me carry it as well as I do). The friends with whom I've been discussing this have been women who weigh about half what I do, so that might have something to do with the results.

What kinda heart rate are you getting to? Do you know? Could you stop for a minute and check?

My heart rate normally hovers around 140-150 BPM during a long workout. Or, at least, that's what the machine's heart sensors tell me it is. If the calories aren't particularly accurate, maybe the heart monitoring system is also inaccurate.
posted by Parasite Unseen at 12:33 PM on October 5, 2009

Does your elliptical measure wattage output? This would be more accurate than a machine's estimate of your calories, and then there are tools available to convert wattage to calories (though this is still an estimate, because of the metabolic variables).
posted by Cool Papa Bell at 1:00 PM on October 5, 2009

I would suggest figuring out your target heart rate, and stick to reaching and maintaining that throughout your workout. It's the most accurate way to know how much you are exerting yourself (ie burning calories). 140-150 sounds low to me if calorie burning is your goal, but crunch the numbers and find out for sure. While some people find cardio machines don't measure their heart rate properly (if I remember correctly, it's something to do with low blood pressure), usually it's pretty accurate. There is nothing subjective about how many times per minute your heart is beating, but how many calories you are burning is a less concrete thing to gauge. If you truly don't trust the machine, you can always buy your own heart rate monitor.
posted by katemcd at 1:39 PM on October 5, 2009 [1 favorite]

Yeah, heart rate is better than calories, better than wattage. Katemcd for the win.
posted by Cool Papa Bell at 1:48 PM on October 5, 2009

If you want to figure out what you burned based on your average heart rate, you can use this handy tool
posted by blue_beetle at 2:11 PM on October 5, 2009 [1 favorite]

650 doesn't sound crazy for 45 minutes at your weight, if you have the resistance set higher than 1. I weigh ~130, and the ellipticals at my gym read about 200 calories for about 20-25 minutes at resistance settings ranging from 6-10 (and varying incline, but mostly at the highest possible).
posted by kestrel251 at 2:52 PM on October 5, 2009

P.S. I also agree with katemcd that 140-150 bpm sounds low, which suggests that you *don't* have the resistance jacked up.
posted by kestrel251 at 2:53 PM on October 5, 2009

Response by poster: 650 doesn't sound crazy for 45 minutes at your weight, if you have the resistance set higher than 1.

I normally have the resistance set to "random", as I've heard that varying the resistance throughout the session gives you the best results in terms of calories burned. There seems to be a lot of conflicting information about whether or not this is accurate.
posted by Parasite Unseen at 3:21 PM on October 5, 2009

150 is not low depending on a) age and b) whether you're trying to lose weight or gain aerobic fitness.

e.g if you're around 30, 150 is at the top of the threshold for weight-losing exercise and the bottom for cardio, depending on overall conditioning.

Don't stress it about the calories, the bpm etc. etc. Know that 45 minutes of any exercise is going to improve your health and wellbeing where exercise=cracking a sweat and breathing heavily. There's no need to overthink unless you're competing or deciding to push yourself (which it doesn't sound like you are). :)
posted by smoke at 3:56 PM on October 5, 2009

Given what you weigh, 650 sounds pretty reasonable (compared to my own experience, with rough rough rough adjustments for weight and time, etc).

People have pointed out it's probably not accurate, but that doesn't matter. What matters is how your numbers compare week to week, if you get in better shape and can burn more calories, or if you can burn the same calories when you weigh less, etc.
posted by where u at dawg at 4:06 PM on October 5, 2009

I noticed the high estimate on several ellipticals also and did some research:

Apparently manufacturers calorie calculations vary depending whether they are based on:
(1) calories burnt as a result of the exercise on the machine
(2) Calories burnt on the machine + calories you would otherwise be burning even if standing still (basal calorie use).

Take your average joe, he burns about 2000 calories / day or nearly 100 for each waking hour (less while asleep). Some machines add this base burnt to your additional burn ... on top of that, they are optimistic about how much you would be burning on your own AND how much their machine is causing you to burn.

The combined impact of over estimating your burn for basal and exercising rates (and including both in the readout) results in a dramatic overestimate relative to many other machines.

Best way I found to calculate the impact of the workout:
(1) determine your basal burn rate by keeping a detailed food diary while not working out. The Daily Plate can be very helpful. (i.e., Daily weight stays the same while consuming X calories)
(2) Add XX minutes of elliptical training to your regimen consistently (every day, every week, 4 times/week, whatever so long as it's consistent). After one month of weigh ins, there will be a difference in weight assuming you maintained your exact calorie intake at your basal rate. Take that lower weight and reverse the calculation to determine your energy use for each minute of elliptical use at a given rate:

Base rate: 2000 cal/day
1 hour of elliptical/day at same rate of rotations
Over 1 month lost 5 pounds = 17,500 calorie deficit/4 weeks
=625 cal deficit / day or per hour of elliptical use.

This is just an example, and it would be very challenging to do this over time to be accurate. Instead, I'd suggest using the estimates at Thedailyplate.com, estimate conservatively, and any underestimation on your part will mean additional weight loss which it's rare to find folks complaining about.
posted by unclezeb at 5:51 PM on October 5, 2009

Also, because every elliptical I've seen only asks for weight not height, and AFAIK doesn't really do any complex calculation of biomechanics, you may well be getting a skewed output because you're relatively fit for your weight. (That the machine is using weight, rather than BMI, basically.)
posted by mercredi at 6:14 PM on October 5, 2009

This is usually discussed in terms of metabolic equivalents (MET). The equation is something like:

Calories Burned = MET value * BMR * (activity duration in hours / 24)

So using 'watching tv' as a base unit, slow walking burns twice the calories, sex three times as many, jogging about seven times.

Anyways, counting calories burned like this is probably a distraction from your goals, as the last twenty five years of research suggests that exercise is not particularly effective for weight loss.
posted by zentrification at 9:53 PM on October 5, 2009

To benchmark: running or walking burns approximately 100 calories per mile. Personally, I find the elliptical less intense and I'd put 100 calories per mile at pretty close to the max I could do on the elliptical.

All of this is highly variable based on your size and fitness level. It's also not something where you need to get overly fussy. Consistent workouts are awesome - even if they aren't burning gobs of calories.
posted by 26.2 at 10:36 PM on October 5, 2009

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