Heart Rate Monitors and Calculating Calories
February 19, 2010 11:45 PM   Subscribe

I've been working hard on my eating habits in order to lose weight; now I need to start exercising. What's the best way to calculate how many calories I'm burning when I do cardio?

I'm thinking about purchasing a heart rate monitor with GPS (or the ability to add GPS later), but I'm uncertain as to whether that's the best option. If it matters, I'm planning on starting by using elliptical and treadmill machines at the gym. This fall, after I get in a shape that is slightly less round and the weather gets cooler, I'm going to start training for a half marathon outside. It would seem that GPS would come in handy at this piont.

Heart rate monitor or something else? Please explain your answer and offer product recommendations!
posted by Aleen to Health & Fitness (14 answers total) 5 users marked this as a favorite
All of this is just tracking and estimating. That's it. You could google the information on calorie burning just as well and have the same certainty.

I don't want to rain on your parade. People need to keep track of things like times and calories and whatever. But nothing can realistically do that.

Just work out hard, do it straight, and catalog it that way. Maybe get a pedometer.
posted by sanka at 11:50 PM on February 19, 2010 [1 favorite]

The elliptical and treadmill machines at the gym will count calories and heart rate, just ask your instructor how to set it up.

As for GPS, I've got a Symbian Nokia phone and I use Sports Tracker to let me know how far I've run/cycled. I'm sure there's a similar app for the iPhone.
posted by hnnrs at 2:01 AM on February 20, 2010

I've read varying opinions about the accuracy of calorie counters on the workout machines. I'm sure you could get an accurate heart rate monitor, but not sure that's reliably translatable to calorie burn.

One thing to keep in mind is the difference between total calories burned (includes basal metabolism) and net calories burned (just what's attributable to the exercise itself). Or maybe this is one of those exercise urban legends.

In the end I think I agree with sanka that the best thing to do is work out at an intensity that challenges you but doesn't knock you flat, and let the numbers take care of themselves. Have fun!

(P.S. Not that you asked but I'm on a tear about this lately: make sure you're getting enough iron in your diet. I noticed a huge improvement in my aerobic capacity after I failed my Red Cross iron test and started eating higher-iron foods.)
posted by lakeroon at 2:16 AM on February 20, 2010

You can really only estimate, but you should be able to get within about 20%. I've used calculators online for running, or the built in calculators on cardio equipment. My elliptical at home is way off, like by a factor of 2 compared to the ones at the gym based on how much effort it feels like I'm putting in, so I just divide whatever it tells me by two.

As long as you're "in the ballpark" as far as calories go, you'll lose weight. If you're not losing weight, you're doing it wrong.


That said, you actually can measure calories burned directly using what's called Indirect Calorimetry, which literally measures the amount of oxygen consumed boy your body. Testing devices are very expensive. This one doesn't even have a price listed, but it is experimentally validated
posted by delmoi at 2:21 AM on February 20, 2010

(Looks like you can get a used full sized version for about $750-$3,500, which is apparently a rack full of equipment )
posted by delmoi at 2:25 AM on February 20, 2010

The elliptical and treadmill machines at the gym will count calories and heart rate, just ask your instructor how to set it up.

ugh. those things are ridiculously inaccurate. while wearing my monitor on a treadmill, it records me as burning about 500 calories, whereas i actually burn more like 1200 with a decent run and 1600 if i'm making like i'm being chased by zombies.

a heart rate monitor is more exact, and can be more precisely tuned to what you actually expend while working out. i use this polar; it gets me to within 5% of what i'm actually doing according to my calorimetric results. you can get a decent basic one from nike.
posted by patricking at 5:48 AM on February 20, 2010

You burn more calories by raising your metabolism. The calories you burn doing cardio is just a part of it. Just do the cardio for 20+ minutes so your metabolism remains elevated when you're done. Results that make any difference need to be longer term than the way you want to measure.
posted by Obscure Reference at 6:07 AM on February 20, 2010

Measuring calories burned by any method except insanely expensive ones (like delmoi linked to) is ridiculously inaccurate to the point of unusability. It's like the scales with the body fat measurements built into them.

Don't try to incorporate "calories burned" into your weight-loss calculations. Keep at the same calorie levels you were at when you were losing weight. If the weight starts coming off too fast or your energy/performance in the gym is affected, each week increase your daily caloric allowance by about 200 calories a day until you reach a weight loss rate that strikes a good balance between results and health.
posted by schroedinger at 6:42 AM on February 20, 2010

The people on the Biggest Loser use the Bodybugg (or something like it). I have never used it, but it claims to give you a more accurate listing of your caloric use during the day.
posted by bove at 6:59 AM on February 20, 2010

Don't waste your time with calculating the EXACT calories. The monitors are pretty inaccurate.

What is accurate is perceived exertion. There are a fair number of valid studies that indicate most of us can accurately measure how hard we're working. (Here's an except of one.) You may be able to bs your personal trainer or manipulate the calorie monitor, but it's pretty hard to lie to yourself. You know if you lamed-out on your workout.

Here is one way to set exertion goals for a week:
1 30 minute workout of intervals - 4 minutes moderate/1 minute high intensity.
1 30 minute pyramid workout - 4 minute low, 6 minute moderate, 4 minute high, 1 minute very high, 4 minute high, 6 minutes moderate, 5 minutes low
1 40 minute workout steady state - 40 minutes moderate

That would give you a pretty balanced cardio routine - intervals, builds and endurance work. You're heart will thank you for it.

Focusing on intensity customizes your workout to your level. If a fast walk is very high intensity for you, then great. If very high intensity is running a 4 minute mile, great. If you work out in the pool, fine. You just get the intensity in whatever workout you're doing that day.
posted by 26.2 at 9:08 AM on February 20, 2010 [2 favorites]

I have similar goals as you -- I'm on week 7 of my "Operation 10k run/30-lb Gut Drop" program and the results have been outstanding thus far. Here's my technique:

1. Follow these steps to calculate your target calorie intake on rest days and active days. This formula takes into account the type and intensity level of your exercise program to average the calories burned during each workout.
2. Search for a xxxx-calorie meal plan, based on the results of step 1 (you may want to compare several plans for the one that's best for you).
3. Find a training program that helps you avoid burnout and injury. I HIGHLY recommend the Couch to 5K program, which is designed to get you from the floor to running 5k in 9 weeks. It's brilliant -- on week one, you'll run 60 second intervals with 90 second rests between each set (in my case, huffing and puffing between sets). Six weeks later, you'll be running 25-30 minutes non-stop without getting winded.

For best results, train using this C25K podcast or, even better, if you have the gadgetry, grab the C25K app for iPhone/iPod Touch or Android phone. The great thing about the app is that you can cue up a playlist of your own music and simply follow the audio cues to run or walk when prompted. When you finish the 9-week program, you can move on to 5k to 10k/half-marathon/marathon programs.

Best of luck and have fun -
posted by prinado at 10:05 AM on February 20, 2010 [1 favorite]

If you go with a heart rate monitor for these purposes, do some research on how accurate the particular device is for estimating calories burned. Mine is great at accuracy for heart rate, but I'm pretty sure it grossly overestimates calorie burn. So I use my HRM as a proxy for how hard I'm working.

I've heard good things about the bodybugg, and almost bought one myself, but I stuck with the iPhone LoseIt app for a little longer and that seemed to work as long as I was dilligent about recording workouts and food intake. The calorie estimates on the app seem to be pretty consistent with other online calculators. So before you drop cash on a particular device it's worth checking out various online calculators to see what seems to align with your own body.
posted by Terriniski at 12:20 PM on February 20, 2010

Best practice is to not count calories, but rather something you can associate with the world around you. I count the time I've run, I know some people who remember land marks and attempt to reach them then return. Something along those lines, a calorie goal will only lead to under working yourself (especially when your metabolism kicks in and you burn more, quicker).
posted by RawrGulMuffins at 8:50 PM on February 20, 2010

I like my heart rate monitor, though it is somewhat uncomfortable (it's like wearing an extra bra), because it gives me an instantaneous third party measurement of how hard I'm working. Which, as someone who hadn't exercised much up until then and so didn't really know what exerting myself felt like, was really useful. I have the girly red Polar, which is considered a good brand.

The calorie counting, whilst probably not all that accurate, is at least comparable across different types of activity, and takes into account my improving fitness level. I don't trust the calorie counters on equipment as they can't distinguish between me, slow overweight non-athlete struggling to maintain a jog, and the really fit tall long legged 20yr old who would barely break a sweat at the speed I'm doing, even though we weigh the same.
posted by kjs4 at 6:23 PM on February 21, 2010

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